.devcontainer/on-create-command.sh

@@ -1,7 +1,9 @@
 #!/bin/bash
 set -e
-python3 -m venv --upgrade-deps .venv
+
+python3 -m venv .venv
 . .venv/bin/activate
+pip install -U pip
 pip install -r requirements/dev.txt
 pip install -e .
 pre-commit install --install-hooks

.editorconfig

@@ -9,5 +9,5 @@ end_of_line = lf
 charset = utf-8
 max_line_length = 88
 
-[*.{css,html,js,json,jsx,scss,ts,tsx,yaml,yml}]
+[*.{yml,yaml,json,js,css,html}]
 indent_size = 2

.github/ISSUE_TEMPLATE/bug-report.md

@@ -5,7 +5,7 @@ about: Report a bug in Flask (not other projects which depend on Flask)
 
 <!--
 This issue tracker is a tool to address bugs in Flask itself. Please use
-GitHub Discussions or the Pallets Discord for questions about your own code.
+Pallets Discord or Stack Overflow for questions about your own code.
 
 Replace this comment with a clear outline of what the bug is.
 -->

.github/ISSUE_TEMPLATE/config.yml

@@ -1,11 +1,11 @@
 blank_issues_enabled: false
 contact_links:
   - name: Security issue
-    url: https://github.com/pallets/flask/security/advisories/new
-    about: Do not report security issues publicly. Create a private advisory.
-  - name: Questions on GitHub Discussions
-    url: https://github.com/pallets/flask/discussions/
-    about: Ask questions about your own code on the Discussions tab.
-  - name: Questions on Discord
+    url: security@palletsprojects.com
+    about: Do not report security issues publicly. Email our security contact.
+  - name: Questions
+    url: https://stackoverflow.com/questions/tagged/flask?tab=Frequent
+    about: Search for and ask questions about your code on Stack Overflow.
+  - name: Questions and discussions
     url: https://discord.gg/pallets
-    about: Ask questions about your own code on our Discord chat.
+    about: Discuss questions about your code on our Discord chat.

.github/SECURITY.md

@@ -0,0 +1,19 @@
+# Security Policy
+
+If you believe you have identified a security issue with a Pallets
+project, **do not open a public issue**. To responsibly report a
+security issue, please email security@palletsprojects.com. A security
+team member will contact you acknowledging the report and how to
+continue.
+
+Be sure to include as much detail as necessary in your report. As with
+reporting normal issues, a minimal reproducible example will help the
+maintainers address the issue faster. If you are able, you may also
+include a fix for the issue generated with `git format-patch`.
+
+The current and previous release will receive security patches, with
+older versions evaluated based on usage information and severity.
+
+After fixing an issue, we will make a security release along with an
+announcement on our blog. We may obtain a CVE id as well. You may
+include a name and link if you would like to be credited for the report.

.github/dependabot.yml

@@ -0,0 +1,9 @@
+version: 2
+updates:
+- package-ecosystem: "github-actions"
+  directory: "/"
+  schedule:
+    interval: "monthly"
+    day: "monday"
+    time: "16:00"
+    timezone: "UTC"

.github/pull_request_template.md

@@ -1,7 +1,6 @@
 <!--
 Before opening a PR, open a ticket describing the issue or feature the
-PR will address. An issue is not required for fixing typos in
-documentation, or other simple non-code changes.
+PR will address. Follow the steps in CONTRIBUTING.rst.
 
 Replace this comment with a description of the change. Describe how it
 addresses the linked ticket.
@@ -10,16 +9,22 @@ addresses the linked ticket.
 <!--
 Link to relevant issues or previous PRs, one per line. Use "fixes" to
 automatically close an issue.
-
-fixes #<issue number>
 -->
 
+- fixes #<issue number>
+
 <!--
-Ensure each step in CONTRIBUTING.rst is complete, especially the following:
+Ensure each step in CONTRIBUTING.rst is complete by adding an "x" to
+each box below.
 
-- Add tests that demonstrate the correct behavior of the change. Tests
-  should fail without the change.
-- Add or update relevant docs, in the docs folder and in code.
-- Add an entry in CHANGES.rst summarizing the change and linking to the issue.
-- Add `.. versionchanged::` entries in any relevant code docs.
+If only docs were changed, these aren't relevant and can be removed.
 -->
+
+Checklist:
+
+- [ ] Add tests that demonstrate the correct behavior of the change. Tests should fail without the change.
+- [ ] Add or update relevant docs, in the docs folder and in code.
+- [ ] Add an entry in `CHANGES.rst` summarizing the change and linking to the issue.
+- [ ] Add `.. versionchanged::` entries in any relevant code docs.
+- [ ] Run `pre-commit` hooks and fix any issues.
+- [ ] Run `pytest` and `tox`, no tests failed.

.github/workflows/lock.yaml

@@ -1,26 +1,21 @@
-name: Lock inactive closed issues
-# Lock closed issues that have not received any further activity for two weeks.
-# This does not close open issues, only humans may do that. It is easier to
-# respond to new issues with fresh examples rather than continuing discussions
-# on old issues.
-
+name: 'Lock threads'
+# Lock closed issues that have not received any further activity for
+# two weeks. This does not close open issues, only humans may do that.
+# We find that it is easier to respond to new issues with fresh examples
+# rather than continuing discussions on old issues.
 on:
   schedule:
     - cron: '0 0 * * *'
-permissions: {}
+permissions:
+  issues: write
+  pull-requests: write
 concurrency:
   group: lock
-  cancel-in-progress: true
 jobs:
   lock:
     runs-on: ubuntu-latest
-    permissions:
-      issues: write
-      pull-requests: write
-      discussions: write
     steps:
-      - uses: dessant/lock-threads@7266a7ce5c1df01b1c6db85bf8cd86c737dadbe7 # v6.0.0
+      - uses: dessant/lock-threads@7de207be1d3ce97a9abe6ff1306222982d1ca9f9
         with:
           issue-inactive-days: 14
           pr-inactive-days: 14
-          discussion-inactive-days: 14

.github/workflows/pre-commit.yaml

@@ -1,29 +0,0 @@
-name: pre-commit
-on:
-  pull_request:
-  push:
-    branches: [main, stable]
-permissions: {}
-concurrency:
-  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
-  cancel-in-progress: true
-jobs:
-  main:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
-        with:
-          persist-credentials: false
-      - uses: astral-sh/setup-uv@cec208311dfd045dd5311c1add060b2062131d57 # v8.0.0
-        with:
-          enable-cache: true
-          prune-cache: false
-      - uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
-        id: setup-python
-        with:
-          python-version-file: pyproject.toml
-      - uses: actions/cache@668228422ae6a00e4ad889ee87cd7109ec5666a7 # v5.0.4
-        with:
-          path: ~/.cache/pre-commit
-          key: pre-commit|${{ hashFiles('pyproject.toml', '.pre-commit-config.yaml') }}
-      - run: uv run --locked --no-default-groups --group pre-commit pre-commit run --show-diff-on-failure --color=always --all-files

.github/workflows/publish.yaml

@@ -1,62 +1,69 @@
 name: Publish
 on:
   push:
-    tags: ['*']
-permissions: {}
-concurrency:
-  group: publish-${{ github.event.push.ref }}
-  cancel-in-progress: true
+    tags:
+      - '*'
 jobs:
   build:
     runs-on: ubuntu-latest
     outputs:
-      artifact-id: ${{ steps.upload-artifact.outputs.artifact-id }}
+      hash: ${{ steps.hash.outputs.hash }}
     steps:
-      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+      - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11
+      - uses: actions/setup-python@0a5c61591373683505ea898e09a3ea4f39ef2b9c
         with:
-          persist-credentials: false
-      - uses: astral-sh/setup-uv@cec208311dfd045dd5311c1add060b2062131d57 # v8.0.0
-        with:
-          enable-cache: false
-          prune-cache: false
-      - uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
-        with:
-          python-version-file: pyproject.toml
+          python-version: '3.x'
+          cache: pip
+          cache-dependency-path: requirements*/*.txt
+      - run: pip install -r requirements/build.txt
+      # Use the commit date instead of the current date during the build.
       - run: echo "SOURCE_DATE_EPOCH=$(git log -1 --pretty=%ct)" >> $GITHUB_ENV
-      - run: uv build
-      - uses: actions/upload-artifact@bbbca2ddaa5d8feaa63e36b76fdaad77386f024f # v7.0.0
-        id: upload-artifact
+      - run: python -m build
+      # Generate hashes used for provenance.
+      - name: generate hash
+        id: hash
+        run: cd dist && echo "hash=$(sha256sum * | base64 -w0)" >> $GITHUB_OUTPUT
+      - uses: actions/upload-artifact@a8a3f3ad30e3422c9c7b888a15615d19a852ae32
         with:
           name: dist
-          path: dist/
-          if-no-files-found: error
-  create-release:
+          path: ./dist
+  provenance:
     needs: [build]
+    permissions:
+      actions: read
+      id-token: write
+      contents: write
+    # Can't pin with hash due to how this workflow works.
+    uses: slsa-framework/slsa-github-generator/.github/workflows/generator_generic_slsa3.yml@v1.9.0
+    with:
+      base64-subjects: ${{ needs.build.outputs.hash }}
+  create-release:
+    # Upload the sdist, wheels, and provenance to a GitHub release. They remain
+    # available as build artifacts for a while as well.
+    needs: [provenance]
     runs-on: ubuntu-latest
     permissions:
       contents: write
     steps:
-      - uses: actions/download-artifact@3e5f45b2cfb9172054b4087a40e8e0b5a5461e7c # v8.0.1
-        with:
-          artifact-ids: ${{ needs.build.outputs.artifact-id }}
-          path: dist/
+      - uses: actions/download-artifact@9bc31d5ccc31df68ecc42ccf4149144866c47d8a
       - name: create release
-        run: gh release create --draft --repo ${GITHUB_REPOSITORY} ${GITHUB_REF_NAME} dist/*
+        run: >
+          gh release create --draft --repo ${{ github.repository }}
+          ${{ github.ref_name }}
+          *.intoto.jsonl/* dist/*
         env:
           GH_TOKEN: ${{ github.token }}
   publish-pypi:
-    needs: [build]
-    environment:
-      name: publish
-      url: https://pypi.org/project/Flask/${{ github.ref_name }}
+    needs: [provenance]
+    # Wait for approval before attempting to upload to PyPI. This allows reviewing the
+    # files in the draft release.
+    environment: publish
     runs-on: ubuntu-latest
     permissions:
       id-token: write
     steps:
-      - uses: actions/download-artifact@3e5f45b2cfb9172054b4087a40e8e0b5a5461e7c # v8.0.1
+      - uses: actions/download-artifact@9bc31d5ccc31df68ecc42ccf4149144866c47d8a
+      - uses: pypa/gh-action-pypi-publish@f946db0f765b9ae754e44bfd5ae5b8b91cfb37ef
         with:
-          artifact-ids: ${{ needs.build.outputs.artifact-id }}
-          path: dist/
-      - uses: pypa/gh-action-pypi-publish@ed0c53931b1dc9bd32cbe73a98c7f6766f8a527e # v1.13.0
-        with:
-          packages-dir: "dist/"
+          repository-url: https://test.pypi.org/legacy/
+      - uses: pypa/gh-action-pypi-publish@f946db0f765b9ae754e44bfd5ae5b8b91cfb37ef

.github/workflows/tests.yaml

@@ -1,63 +1,49 @@
 name: Tests
 on:
-  pull_request:
-    paths-ignore: ['docs/**', 'README.md']
   push:
-    branches: [main, stable]
-    paths-ignore: ['docs/**', 'README.md']
-permissions: {}
-concurrency:
-  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
-  cancel-in-progress: true
+    branches:
+      - main
+      - '*.x'
+    paths-ignore:
+      - 'docs/**'
+      - '*.md'
+      - '*.rst'
+  pull_request:
+    paths-ignore:
+      - 'docs/**'
+      - '*.md'
+      - '*.rst'
 jobs:
   tests:
-    name: ${{ matrix.name || matrix.python }}
-    runs-on: ${{ matrix.os || 'ubuntu-latest' }}
+    name: ${{ matrix.name }}
+    runs-on: ${{ matrix.os }}
     strategy:
       fail-fast: false
       matrix:
         include:
-          - {python: '3.14'}
-          - {python: '3.14t'}
-          - {name: Windows, python: '3.14', os: windows-latest}
-          - {name: Mac, python: '3.14', os: macos-latest}
-          - {python: '3.13'}
-          - {python: '3.12'}
-          - {python: '3.11'}
-          - {python: '3.10'}
-          - {name: PyPy, python: 'pypy-3.11', tox: pypy3.11}
-          - {name: Minimum Versions, python: '3.14', tox: tests-min}
-          - {name: Development Versions, python: '3.10', tox: tests-dev}
+          - {name: Linux, python: '3.12', os: ubuntu-latest, tox: py312}
+          - {name: Windows, python: '3.12', os: windows-latest, tox: py312}
+          - {name: Mac, python: '3.12', os: macos-latest, tox: py312}
+          - {name: '3.11', python: '3.11', os: ubuntu-latest, tox: py311}
+          - {name: '3.10', python: '3.10', os: ubuntu-latest, tox: py310}
+          - {name: '3.9', python: '3.9', os: ubuntu-latest, tox: py39}
+          - {name: '3.8', python: '3.8', os: ubuntu-latest, tox: py38}
+          - {name: 'PyPy', python: 'pypy-3.10', os: ubuntu-latest, tox: pypy310}
+          - {name: 'Minimum Versions', python: '3.12', os: ubuntu-latest, tox: py312-min}
+          - {name: 'Development Versions', python: '3.8', os: ubuntu-latest, tox: py38-dev}
+          - {name: Typing, python: '3.12', os: ubuntu-latest, tox: typing}
     steps:
-      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
-        with:
-          persist-credentials: false
-      - uses: astral-sh/setup-uv@cec208311dfd045dd5311c1add060b2062131d57 # v8.0.0
-        with:
-          enable-cache: true
-          prune-cache: false
-      - uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
+      - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11
+      - uses: actions/setup-python@0a5c61591373683505ea898e09a3ea4f39ef2b9c
         with:
           python-version: ${{ matrix.python }}
-      - run: uv run --locked --no-default-groups --group dev tox run
-        env:
-          TOX_ENV: ${{ matrix.tox || format('py{0}', matrix.python) }}
-  typing:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
-        with:
-          persist-credentials: false
-      - uses: astral-sh/setup-uv@cec208311dfd045dd5311c1add060b2062131d57 # v8.0.0
-        with:
-          enable-cache: true
-          prune-cache: false
-      - uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
-        with:
-          python-version-file: pyproject.toml
+          cache: 'pip'
+          cache-dependency-path: requirements*/*.txt
       - name: cache mypy
-        uses: actions/cache@668228422ae6a00e4ad889ee87cd7109ec5666a7 # v5.0.4
+        uses: actions/cache@13aacd865c20de90d75de3b17ebe84f7a17d57d2
         with:
           path: ./.mypy_cache
-          key: mypy|${{ hashFiles('pyproject.toml') }}
-      - run: uv run --locked --no-default-groups --group dev tox run -e typing
+          key: mypy|${{ matrix.python }}|${{ hashFiles('pyproject.toml') }}
+        if: matrix.tox == 'typing'
+      - run: pip install tox
+      - run: tox run -e ${{ matrix.tox }}

.github/workflows/zizmor.yaml

@@ -1,22 +0,0 @@
-name: GitHub Actions security analysis with zizmor
-on:
-  pull_request:
-    paths: ["**/*.yaml?"]
-  push:
-    branches: [main, stable]
-    paths: ["**/*.yaml?"]
-permissions: {}
-concurrency:
-  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
-  cancel-in-progress: true
-jobs:
-  zizmor:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
-        with:
-          persist-credentials: false
-      - uses: zizmorcore/zizmor-action@71321a20a9ded102f6e9ce5718a2fcec2c4f70d8 # v0.5.2
-        with:
-          advanced-security: false
-          annotations: true

.gitignore

@@ -1,8 +1,10 @@
 .idea/
 .vscode/
 __pycache__/
-dist/
-.coverage*
-htmlcov/
 .tox/
+.coverage
+.coverage.*
+htmlcov/
 docs/_build/
+dist/
+venv/

.pre-commit-config.yaml

@@ -1,20 +1,13 @@
+ci:
+  autoupdate_schedule: monthly
 repos:
   - repo: https://github.com/astral-sh/ruff-pre-commit
-    rev: 5e2fb545eba1ea9dc051f6f962d52fe8f76a9794  # frozen: v0.15.13
+    rev: v0.1.13
     hooks:
-      - id: ruff-check
+      - id: ruff
       - id: ruff-format
-  - repo: https://github.com/astral-sh/uv-pre-commit
-    rev: fa60a193803535a9e2accdb3ca4b1b584b1150cb  # frozen: 0.11.15
-    hooks:
-      - id: uv-lock
-  - repo: https://github.com/codespell-project/codespell
-    rev: 2ccb47ff45ad361a21071a7eedda4c37e6ae8c5a  # frozen: v2.4.2
-    hooks:
-      - id: codespell
-        args: ['--write-changes']
   - repo: https://github.com/pre-commit/pre-commit-hooks
-    rev: 3e8a8703264a2f4a69428a0aa4dcb512790b2c8c  # frozen: v6.0.0
+    rev: v4.5.0
     hooks:
       - id: check-merge-conflict
       - id: debug-statements

.readthedocs.yaml

@@ -1,10 +1,13 @@
 version: 2
 build:
-  os: ubuntu-24.04
+  os: ubuntu-22.04
   tools:
-    python: '3.13'
-  commands:
-    - asdf plugin add uv
-    - asdf install uv latest
-    - asdf global uv latest
-    - uv run --group docs sphinx-build -W -b dirhtml docs $READTHEDOCS_OUTPUT/html
+    python: "3.12"
+python:
+  install:
+    - requirements: requirements/docs.txt
+    - method: pip
+      path: .
+sphinx:
+  builder: dirhtml
+  fail_on_warning: true

CHANGES.rst

@@ -1,130 +1,9 @@
-Version 3.2.0
--------------
-
-Unreleased
-
--   Drop support for Python 3.9. :pr:`5730`
--   Remove previously deprecated code: ``__version__``. :pr:`5648`
--   ``RequestContext`` has merged with ``AppContext``. ``RequestContext`` is now
-    a deprecated alias. If an app context is already pushed, it is not reused
-    when dispatching a request. This greatly simplifies the internal code for tracking
-    the active context. :issue:`5639`
--   Many ``Flask`` methods involved in request dispatch now take the current
-    ``AppContext`` as the first parameter, instead of using the proxy objects.
-    If subclasses were overriding these methods, the old signature is detected,
-    shows a deprecation warning, and will continue to work during the
-    deprecation period. :issue:`5815`
--   All teardown callbacks are called, even if any raise an error. :pr:`5928`
--   The ``should_ignore_error`` is deprecated. Handle errors as needed in
-    teardown handlers instead. :issue:`5816`
--   ``template_filter``, ``template_test``, and ``template_global`` decorators
-    can be used without parentheses. :issue:`5729`
--   ``redirect`` returns a ``303`` status code by default instead of ``302``.
-    This tells the client to always switch to ``GET``, rather than only
-    switching ``POST`` to ``GET``. This preserves the current behavior of
-    ``GET`` and ``POST`` redirects, and is also correct for frontend libraries
-    such as HTMX. :issue:`5895`
--   ``provide_automatic_options=True`` can be used to enable it for a view when
-    it's disabled in config. Previously, only disabling worked. :issue:`5916`
--   ``Flask.select_jinja_autoescape`` uses case-insensitive comparison instead
-    of only lower case file extensions. :pr:`6012`
-
-
-Version 3.1.3
--------------
-
-Released 2026-02-18
-
--   The session is marked as accessed for operations that only access the keys
-    but not the values, such as ``in`` and ``len``. :ghsa:`68rp-wp8r-4726`
-
-
-Version 3.1.2
--------------
-
-Released 2025-08-19
-
--   ``stream_with_context`` does not fail inside async views. :issue:`5774`
--   When using ``follow_redirects`` in the test client, the final state
-    of ``session`` is correct. :issue:`5786`
--   Relax type hint for passing bytes IO to ``send_file``. :issue:`5776`
-
-
-Version 3.1.1
--------------
-
-Released 2025-05-13
-
--   Fix signing key selection order when key rotation is enabled via
-    ``SECRET_KEY_FALLBACKS``. :ghsa:`4grg-w6v8-c28g`
--   Fix type hint for ``cli_runner.invoke``. :issue:`5645`
--   ``flask --help`` loads the app and plugins first to make sure all commands
-    are shown. :issue:`5673`
--   Mark sans-io base class as being able to handle views that return
-    ``AsyncIterable``. This is not accurate for Flask, but makes typing easier
-    for Quart. :pr:`5659`
-
-
-Version 3.1.0
--------------
-
-Released 2024-11-13
-
--   Drop support for Python 3.8. :pr:`5623`
--   Update minimum dependency versions to latest feature releases.
-    Werkzeug >= 3.1, ItsDangerous >= 2.2, Blinker >= 1.9. :pr:`5624,5633`
--   Provide a configuration option to control automatic option
-    responses. :pr:`5496`
--   ``Flask.open_resource``/``open_instance_resource`` and
-    ``Blueprint.open_resource`` take an ``encoding`` parameter to use when
-    opening in text mode. It defaults to ``utf-8``. :issue:`5504`
--   ``Request.max_content_length`` can be customized per-request instead of only
-    through the ``MAX_CONTENT_LENGTH`` config. Added
-    ``MAX_FORM_MEMORY_SIZE`` and ``MAX_FORM_PARTS`` config. Added documentation
-    about resource limits to the security page. :issue:`5625`
--   Add support for the ``Partitioned`` cookie attribute (CHIPS), with the
-    ``SESSION_COOKIE_PARTITIONED`` config. :issue:`5472`
--   ``-e path`` takes precedence over default ``.env`` and ``.flaskenv`` files.
-    ``load_dotenv`` loads default files in addition to a path unless
-    ``load_defaults=False`` is passed. :issue:`5628`
--   Support key rotation with the ``SECRET_KEY_FALLBACKS`` config, a list of old
-    secret keys that can still be used for unsigning. Extensions will need to
-    add support. :issue:`5621`
--   Fix how setting ``host_matching=True`` or ``subdomain_matching=False``
-    interacts with ``SERVER_NAME``. Setting ``SERVER_NAME`` no longer restricts
-    requests to only that domain. :issue:`5553`
--   ``Request.trusted_hosts`` is checked during routing, and can be set through
-    the ``TRUSTED_HOSTS`` config. :issue:`5636`
-
-
-Version 3.0.3
--------------
-
-Released 2024-04-07
-
--   The default ``hashlib.sha1`` may not be available in FIPS builds. Don't
-    access it at import time so the developer has time to change the default.
-    :issue:`5448`
--   Don't initialize the ``cli`` attribute in the sansio scaffold, but rather in
-    the ``Flask`` concrete class. :pr:`5270`
-
-
-Version 3.0.2
--------------
-
-Released 2024-02-03
-
--   Correct type for ``jinja_loader`` property. :issue:`5388`
--   Fix error with ``--extra-files`` and ``--exclude-patterns`` CLI options.
-    :issue:`5391`
-
-
 Version 3.0.1
 -------------
 
 Released 2024-01-18
 
--   Correct type for ``path`` argument to ``send_file``. :issue:`5336`
+-   Correct type for ``path`` argument to ``send_file``. :issue:`5230`
 -   Fix a typo in an error message for the ``flask run --key`` option. :pr:`5344`
 -   Session data is untagged without relying on the built-in ``json.loads``
     ``object_hook``. This allows other JSON providers that don't implement that.
@@ -164,7 +43,6 @@ Released 2023-05-01
 
 -   Set ``Vary: Cookie`` header when the session is accessed, modified, or refreshed.
 -   Update Werkzeug requirement to >=2.3.3 to apply recent bug fixes.
-    :ghsa:`m2qf-hxjv-5gpq`
 
 
 Version 2.3.1
@@ -935,7 +813,7 @@ Released 2018-04-26
     explicitly for each exception if you want to avoid traversing the
     MRO. :pr:`2362`
 -   Fix incorrect JSON encoding of aware, non-UTC datetimes. :pr:`2374`
--   Template auto reloading will honor debug mode even if
+-   Template auto reloading will honor debug mode even even if
     ``Flask.jinja_env`` was already accessed. :pr:`2373`
 -   The following old deprecated code was removed. :issue:`2385`
 
@@ -1417,7 +1295,7 @@ Released 2011-09-29, codename Rakija
     of Flask itself and no longer of the test client. This cleaned up
     some internal logic and lowers the odds of runaway request contexts
     in unittests.
--   Fixed the Jinja environment's ``list_templates`` method not
+-   Fixed the Jinja2 environment's ``list_templates`` method not
     returning the correct names when blueprints or modules were
     involved.
 
@@ -1503,7 +1381,7 @@ Released 2010-12-31
 
 -   Fixed an issue where the default ``OPTIONS`` response was not
     exposing all valid methods in the ``Allow`` header.
--   Jinja template loading syntax now allows "./" in front of a
+-   Jinja2 template loading syntax now allows "./" in front of a
     template load path. Previously this caused issues with module
     setups.
 -   Fixed an issue where the subdomain setting for modules was ignored

CODE_OF_CONDUCT.md

@@ -0,0 +1,76 @@
+# Contributor Covenant Code of Conduct
+
+## Our Pledge
+
+In the interest of fostering an open and welcoming environment, we as
+contributors and maintainers pledge to making participation in our project and
+our community a harassment-free experience for everyone, regardless of age, body
+size, disability, ethnicity, sex characteristics, gender identity and expression,
+level of experience, education, socio-economic status, nationality, personal
+appearance, race, religion, or sexual identity and orientation.
+
+## Our Standards
+
+Examples of behavior that contributes to creating a positive environment
+include:
+
+* Using welcoming and inclusive language
+* Being respectful of differing viewpoints and experiences
+* Gracefully accepting constructive criticism
+* Focusing on what is best for the community
+* Showing empathy towards other community members
+
+Examples of unacceptable behavior by participants include:
+
+* The use of sexualized language or imagery and unwelcome sexual attention or
+ advances
+* Trolling, insulting/derogatory comments, and personal or political attacks
+* Public or private harassment
+* Publishing others' private information, such as a physical or electronic
+ address, without explicit permission
+* Other conduct which could reasonably be considered inappropriate in a
+ professional setting
+
+## Our Responsibilities
+
+Project maintainers are responsible for clarifying the standards of acceptable
+behavior and are expected to take appropriate and fair corrective action in
+response to any instances of unacceptable behavior.
+
+Project maintainers have the right and responsibility to remove, edit, or
+reject comments, commits, code, wiki edits, issues, and other contributions
+that are not aligned to this Code of Conduct, or to ban temporarily or
+permanently any contributor for other behaviors that they deem inappropriate,
+threatening, offensive, or harmful.
+
+## Scope
+
+This Code of Conduct applies both within project spaces and in public spaces
+when an individual is representing the project or its community. Examples of
+representing a project or community include using an official project e-mail
+address, posting via an official social media account, or acting as an appointed
+representative at an online or offline event. Representation of a project may be
+further defined and clarified by project maintainers.
+
+## Enforcement
+
+Instances of abusive, harassing, or otherwise unacceptable behavior may be
+reported by contacting the project team at report@palletsprojects.com. All
+complaints will be reviewed and investigated and will result in a response that
+is deemed necessary and appropriate to the circumstances. The project team is
+obligated to maintain confidentiality with regard to the reporter of an incident.
+Further details of specific enforcement policies may be posted separately.
+
+Project maintainers who do not follow or enforce the Code of Conduct in good
+faith may face temporary or permanent repercussions as determined by other
+members of the project's leadership.
+
+## Attribution
+
+This Code of Conduct is adapted from the [Contributor Covenant][homepage], version 1.4,
+available at https://www.contributor-covenant.org/version/1/4/code-of-conduct.html
+
+[homepage]: https://www.contributor-covenant.org
+
+For answers to common questions about this code of conduct, see
+https://www.contributor-covenant.org/faq

CONTRIBUTING.rst

@@ -0,0 +1,238 @@
+How to contribute to Flask
+==========================
+
+Thank you for considering contributing to Flask!
+
+
+Support questions
+-----------------
+
+Please don't use the issue tracker for this. The issue tracker is a tool
+to address bugs and feature requests in Flask itself. Use one of the
+following resources for questions about using Flask or issues with your
+own code:
+
+-   The ``#questions`` channel on our Discord chat:
+    https://discord.gg/pallets
+-   Ask on `Stack Overflow`_. Search with Google first using:
+    ``site:stackoverflow.com flask {search term, exception message, etc.}``
+-   Ask on our `GitHub Discussions`_ for long term discussion or larger
+    questions.
+
+.. _Stack Overflow: https://stackoverflow.com/questions/tagged/flask?tab=Frequent
+.. _GitHub Discussions: https://github.com/pallets/flask/discussions
+
+
+Reporting issues
+----------------
+
+Include the following information in your post:
+
+-   Describe what you expected to happen.
+-   If possible, include a `minimal reproducible example`_ to help us
+    identify the issue. This also helps check that the issue is not with
+    your own code.
+-   Describe what actually happened. Include the full traceback if there
+    was an exception.
+-   List your Python and Flask versions. If possible, check if this
+    issue is already fixed in the latest releases or the latest code in
+    the repository.
+
+.. _minimal reproducible example: https://stackoverflow.com/help/minimal-reproducible-example
+
+
+Submitting patches
+------------------
+
+If there is not an open issue for what you want to submit, prefer
+opening one for discussion before working on a PR. You can work on any
+issue that doesn't have an open PR linked to it or a maintainer assigned
+to it. These show up in the sidebar. No need to ask if you can work on
+an issue that interests you.
+
+Include the following in your patch:
+
+-   Use `Black`_ to format your code. This and other tools will run
+    automatically if you install `pre-commit`_ using the instructions
+    below.
+-   Include tests if your patch adds or changes code. Make sure the test
+    fails without your patch.
+-   Update any relevant docs pages and docstrings. Docs pages and
+    docstrings should be wrapped at 72 characters.
+-   Add an entry in ``CHANGES.rst``. Use the same style as other
+    entries. Also include ``.. versionchanged::`` inline changelogs in
+    relevant docstrings.
+
+.. _Black: https://black.readthedocs.io
+.. _pre-commit: https://pre-commit.com
+
+
+First time setup using GitHub Codespaces
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+`GitHub Codespaces`_ creates a development environment that is already set up for the
+project. By default it opens in Visual Studio Code for the Web, but this can
+be changed in your GitHub profile settings to use Visual Studio Code or JetBrains
+PyCharm on your local computer.
+
+-   Make sure you have a `GitHub account`_.
+-   From the project's repository page, click the green "Code" button and then "Create
+    codespace on main".
+-   The codespace will be set up, then Visual Studio Code will open. However, you'll
+    need to wait a bit longer for the Python extension to be installed. You'll know it's
+    ready when the terminal at the bottom shows that the virtualenv was activated.
+-   Check out a branch and `start coding`_.
+
+.. _GitHub Codespaces: https://docs.github.com/en/codespaces
+.. _devcontainer: https://docs.github.com/en/codespaces/setting-up-your-project-for-codespaces/adding-a-dev-container-configuration/introduction-to-dev-containers
+
+First time setup in your local environment
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+-   Make sure you have a `GitHub account`_.
+-   Download and install the `latest version of git`_.
+-   Configure git with your `username`_ and `email`_.
+
+    .. code-block:: text
+
+        $ git config --global user.name 'your name'
+        $ git config --global user.email 'your email'
+
+-   Fork Flask to your GitHub account by clicking the `Fork`_ button.
+-   `Clone`_ your fork locally, replacing ``your-username`` in the command below with
+    your actual username.
+
+    .. code-block:: text
+
+        $ git clone https://github.com/your-username/flask
+        $ cd flask
+
+-   Create a virtualenv. Use the latest version of Python.
+
+    - Linux/macOS
+
+      .. code-block:: text
+
+         $ python3 -m venv .venv
+         $ . .venv/bin/activate
+
+    - Windows
+
+      .. code-block:: text
+
+         > py -3 -m venv .venv
+         > .venv\Scripts\activate
+
+-   Install the development dependencies, then install Flask in editable mode.
+
+    .. code-block:: text
+
+        $ python -m pip install -U pip
+        $ pip install -r requirements/dev.txt && pip install -e .
+
+-   Install the pre-commit hooks.
+
+    .. code-block:: text
+
+        $ pre-commit install --install-hooks
+
+.. _GitHub account: https://github.com/join
+.. _latest version of git: https://git-scm.com/downloads
+.. _username: https://docs.github.com/en/github/using-git/setting-your-username-in-git
+.. _email: https://docs.github.com/en/github/setting-up-and-managing-your-github-user-account/setting-your-commit-email-address
+.. _Fork: https://github.com/pallets/flask/fork
+.. _Clone: https://docs.github.com/en/github/getting-started-with-github/fork-a-repo#step-2-create-a-local-clone-of-your-fork
+
+.. _start coding:
+
+Start coding
+~~~~~~~~~~~~
+
+-   Create a branch to identify the issue you would like to work on. If you're
+    submitting a bug or documentation fix, branch off of the latest ".x" branch.
+
+    .. code-block:: text
+
+        $ git fetch origin
+        $ git checkout -b your-branch-name origin/2.0.x
+
+    If you're submitting a feature addition or change, branch off of the "main" branch.
+
+    .. code-block:: text
+
+        $ git fetch origin
+        $ git checkout -b your-branch-name origin/main
+
+-   Using your favorite editor, make your changes, `committing as you go`_.
+
+    -   If you are in a codespace, you will be prompted to `create a fork`_ the first
+        time you make a commit. Enter ``Y`` to continue.
+
+-   Include tests that cover any code changes you make. Make sure the test fails without
+    your patch. Run the tests as described below.
+-   Push your commits to your fork on GitHub and `create a pull request`_. Link to the
+    issue being addressed with ``fixes #123`` in the pull request description.
+
+    .. code-block:: text
+
+        $ git push --set-upstream origin your-branch-name
+
+.. _committing as you go: https://afraid-to-commit.readthedocs.io/en/latest/git/commandlinegit.html#commit-your-changes
+.. _create a fork: https://docs.github.com/en/codespaces/developing-in-codespaces/using-source-control-in-your-codespace#about-automatic-forking
+.. _create a pull request: https://docs.github.com/en/github/collaborating-with-issues-and-pull-requests/creating-a-pull-request
+
+.. _Running the tests:
+
+Running the tests
+~~~~~~~~~~~~~~~~~
+
+Run the basic test suite with pytest.
+
+.. code-block:: text
+
+    $ pytest
+
+This runs the tests for the current environment, which is usually
+sufficient. CI will run the full suite when you submit your pull
+request. You can run the full test suite with tox if you don't want to
+wait.
+
+.. code-block:: text
+
+    $ tox
+
+
+Running test coverage
+~~~~~~~~~~~~~~~~~~~~~
+
+Generating a report of lines that do not have test coverage can indicate
+where to start contributing. Run ``pytest`` using ``coverage`` and
+generate a report.
+
+If you are using GitHub Codespaces, ``coverage`` is already installed
+so you can skip the installation command.
+
+.. code-block:: text
+
+    $ pip install coverage
+    $ coverage run -m pytest
+    $ coverage html
+
+Open ``htmlcov/index.html`` in your browser to explore the report.
+
+Read more about `coverage <https://coverage.readthedocs.io>`__.
+
+
+Building the docs
+~~~~~~~~~~~~~~~~~
+
+Build the docs in the ``docs`` directory using Sphinx.
+
+.. code-block:: text
+
+    $ cd docs
+    $ make html
+
+Open ``_build/html/index.html`` in your browser to view the docs.
+
+Read more about `Sphinx <https://www.sphinx-doc.org/en/stable/>`__.

README.md

@@ -1,53 +0,0 @@
-<div align="center"><img src="https://raw.githubusercontent.com/pallets/flask/refs/heads/stable/docs/_static/flask-name.svg" alt="" height="150"></div>
-
-# Flask
-
-Flask is a lightweight [WSGI] web application framework. It is designed
-to make getting started quick and easy, with the ability to scale up to
-complex applications. It began as a simple wrapper around [Werkzeug]
-and [Jinja], and has become one of the most popular Python web
-application frameworks.
-
-Flask offers suggestions, but doesn't enforce any dependencies or
-project layout. It is up to the developer to choose the tools and
-libraries they want to use. There are many extensions provided by the
-community that make adding new functionality easy.
-
-[WSGI]: https://wsgi.readthedocs.io/
-[Werkzeug]: https://werkzeug.palletsprojects.com/
-[Jinja]: https://jinja.palletsprojects.com/
-
-## A Simple Example
-
-```python
-# save this as app.py
-from flask import Flask
-
-app = Flask(__name__)
-
-@app.route("/")
-def hello():
-    return "Hello, World!"
-```
-
-```
-$ flask run
-  * Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)
-```
-
-## Donate
-
-The Pallets organization develops and supports Flask and the libraries
-it uses. In order to grow the community of contributors and users, and
-allow the maintainers to devote more time to the projects, [please
-donate today].
-
-[please donate today]: https://palletsprojects.com/donate
-
-## Contributing
-
-See our [detailed contributing documentation][contrib] for many ways to
-contribute, including reporting issues, requesting features, asking or answering
-questions, and making PRs.
-
-[contrib]: https://palletsprojects.com/contributing/

README.rst

@@ -0,0 +1,80 @@
+Flask
+=====
+
+Flask is a lightweight `WSGI`_ web application framework. It is designed
+to make getting started quick and easy, with the ability to scale up to
+complex applications. It began as a simple wrapper around `Werkzeug`_
+and `Jinja`_ and has become one of the most popular Python web
+application frameworks.
+
+Flask offers suggestions, but doesn't enforce any dependencies or
+project layout. It is up to the developer to choose the tools and
+libraries they want to use. There are many extensions provided by the
+community that make adding new functionality easy.
+
+.. _WSGI: https://wsgi.readthedocs.io/
+.. _Werkzeug: https://werkzeug.palletsprojects.com/
+.. _Jinja: https://jinja.palletsprojects.com/
+
+
+Installing
+----------
+
+Install and update using `pip`_:
+
+.. code-block:: text
+
+    $ pip install -U Flask
+
+.. _pip: https://pip.pypa.io/en/stable/getting-started/
+
+
+A Simple Example
+----------------
+
+.. code-block:: python
+
+    # save this as app.py
+    from flask import Flask
+
+    app = Flask(__name__)
+
+    @app.route("/")
+    def hello():
+        return "Hello, World!"
+
+.. code-block:: text
+
+    $ flask run
+      * Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)
+
+
+Contributing
+------------
+
+For guidance on setting up a development environment and how to make a
+contribution to Flask, see the `contributing guidelines`_.
+
+.. _contributing guidelines: https://github.com/pallets/flask/blob/main/CONTRIBUTING.rst
+
+
+Donate
+------
+
+The Pallets organization develops and supports Flask and the libraries
+it uses. In order to grow the community of contributors and users, and
+allow the maintainers to devote more time to the projects, `please
+donate today`_.
+
+.. _please donate today: https://palletsprojects.com/donate
+
+
+Links
+-----
+
+-   Documentation: https://flask.palletsprojects.com/
+-   Changes: https://flask.palletsprojects.com/changes/
+-   PyPI Releases: https://pypi.org/project/Flask/
+-   Source Code: https://github.com/pallets/flask/
+-   Issue Tracker: https://github.com/pallets/flask/issues/
+-   Chat: https://discord.gg/pallets

docs/_static/flask-icon.svg

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docs/_static/flask-logo.svg

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docs/_static/flask-name.svg

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docs/api.rst

@@ -31,15 +31,17 @@ Incoming Request Data
     :inherited-members:
     :exclude-members: json_module
 
-.. data:: request
+.. attribute:: request
 
-    A proxy to the request data for the current request, an instance of
-    :class:`.Request`.
+   To access incoming request data, you can use the global `request`
+   object. Flask parses incoming request data for you and gives you
+   access to it through that global object. Internally Flask makes
+   sure that you always get the correct data for the active thread if you
+   are in a multithreaded environment.
 
-    This is only available when a :doc:`request context </appcontext>` is
-    active.
+   This is a proxy. See :ref:`notes-on-proxies` for more information.
 
-    This is a proxy. See :ref:`context-visibility` for more information.
+   The request object is an instance of a :class:`~flask.Request`.
 
 
 Response Objects
@@ -60,33 +62,40 @@ does this is by using a signed cookie. The user can look at the session
 contents, but can't modify it unless they know the secret key, so make sure to
 set that to something complex and unguessable.
 
-To access the current session you can use the :data:`.session` proxy.
+To access the current session you can use the :class:`session` object:
 
-.. data:: session
+.. class:: session
 
-    A proxy to the session data for the current request, an instance of
-    :class:`.SessionMixin`.
+   The session object works pretty much like an ordinary dict, with the
+   difference that it keeps track of modifications.
 
-    This is only available when a :doc:`request context </appcontext>` is
-    active.
+   This is a proxy. See :ref:`notes-on-proxies` for more information.
 
-    This is a proxy. See :ref:`context-visibility` for more information.
+   The following attributes are interesting:
 
-    The session object works like a dict but tracks assignment and access to its
-    keys. It cannot track modifications to mutable values, you need to set
-    :attr:`~.SessionMixin.modified` manually when modifying a list, dict, etc.
+   .. attribute:: new
 
-    .. code-block:: python
+      ``True`` if the session is new, ``False`` otherwise.
 
-          # appending to a list is not detected
-          session["numbers"].append(42)
+   .. attribute:: modified
+
+      ``True`` if the session object detected a modification. Be advised
+      that modifications on mutable structures are not picked up
+      automatically, in that situation you have to explicitly set the
+      attribute to ``True`` yourself. Here an example::
+
+          # this change is not picked up because a mutable object (here
+          # a list) is changed.
+          session['objects'].append(42)
           # so mark it as modified yourself
           session.modified = True
 
-    The session is persisted across requests using a cookie. By default the
-    users's browser will clear the cookie when it is closed. Set
-    :attr:`~.SessionMixin.permanent` to ``True`` to persist the cookie for
-    :data:`PERMANENT_SESSION_LIFETIME`.
+   .. attribute:: permanent
+
+      If set to ``True`` the session lives for
+      :attr:`~flask.Flask.permanent_session_lifetime` seconds. The
+      default is 31 days. If set to ``False`` (which is the default) the
+      session will be deleted when the user closes the browser.
 
 
 Session Interface
@@ -149,21 +158,20 @@ another, a global variable is not good enough because it would break in
 threaded environments. Flask provides you with a special object that
 ensures it is only valid for the active request and that will return
 different values for each request. In a nutshell: it does the right
-thing, like it does for :data:`.request` and :data:`.session`.
+thing, like it does for :class:`request` and :class:`session`.
 
 .. data:: g
 
-    A proxy to a namespace object used to store data during a single request or
-    app context. An instance of :attr:`.Flask.app_ctx_globals_class`, which
-    defaults to :class:`._AppCtxGlobals`.
+    A namespace object that can store data during an
+    :doc:`application context </appcontext>`. This is an instance of
+    :attr:`Flask.app_ctx_globals_class`, which defaults to
+    :class:`ctx._AppCtxGlobals`.
 
-    This is a good place to store resources during a request. For example, a
-    :meth:`~.Flask.before_request` function could load a user object from a
-    session id, then set ``g.user`` to be used in the view function.
+    This is a good place to store resources during a request. For
+    example, a ``before_request`` function could load a user object from
+    a session id, then set ``g.user`` to be used in the view function.
 
-    This is only available when an :doc:`app context </appcontext>` is active.
-
-    This is a proxy. See :ref:`context-visibility` for more information.
+    This is a proxy. See :ref:`notes-on-proxies` for more information.
 
     .. versionchanged:: 0.10
         Bound to the application context instead of the request context.
@@ -177,16 +185,17 @@ Useful Functions and Classes
 
 .. data:: current_app
 
-    A proxy to the :class:`.Flask` application handling the current request or
-    other activity.
+    A proxy to the application handling the current request. This is
+    useful to access the application without needing to import it, or if
+    it can't be imported, such as when using the application factory
+    pattern or in blueprints and extensions.
 
-    This is useful to access the application without needing to import it, or if
-    it can't be imported, such as when using the application factory pattern or
-    in blueprints and extensions.
+    This is only available when an
+    :doc:`application context </appcontext>` is pushed. This happens
+    automatically during requests and CLI commands. It can be controlled
+    manually with :meth:`~flask.Flask.app_context`.
 
-    This is only available when an :doc:`app context </appcontext>` is active.
-
-    This is a proxy. See :ref:`context-visibility` for more information.
+    This is a proxy. See :ref:`notes-on-proxies` for more information.
 
 .. autofunction:: has_request_context
 
@@ -290,31 +299,31 @@ Stream Helpers
 Useful Internals
 ----------------
 
+.. autoclass:: flask.ctx.RequestContext
+   :members:
+
+.. data:: flask.globals.request_ctx
+
+    The current :class:`~flask.ctx.RequestContext`. If a request context
+    is not active, accessing attributes on this proxy will raise a
+    ``RuntimeError``.
+
+    This is an internal object that is essential to how Flask handles
+    requests. Accessing this should not be needed in most cases. Most
+    likely you want :data:`request` and :data:`session` instead.
+
 .. autoclass:: flask.ctx.AppContext
    :members:
 
 .. data:: flask.globals.app_ctx
 
-    A proxy to the active :class:`.AppContext`.
+    The current :class:`~flask.ctx.AppContext`. If an app context is not
+    active, accessing attributes on this proxy will raise a
+    ``RuntimeError``.
 
-    This is an internal object that is essential to how Flask handles requests.
-    Accessing this should not be needed in most cases. Most likely you want
-    :data:`.current_app`, :data:`.g`, :data:`.request`, and :data:`.session` instead.
-
-    This is only available when a :doc:`request context </appcontext>` is
-    active.
-
-    This is a proxy. See :ref:`context-visibility` for more information.
-
-.. class:: flask.ctx.RequestContext
-
-    .. deprecated:: 3.2
-        Merged with :class:`AppContext`. This alias will be removed in Flask 4.0.
-
-.. data:: flask.globals.request_ctx
-
-    .. deprecated:: 3.2
-        Merged with :data:`.app_ctx`. This alias will be removed in Flask 4.0.
+    This is an internal object that is essential to how Flask handles
+    requests. Accessing this should not be needed in most cases. Most
+    likely you want :data:`current_app` and :data:`g` instead.
 
 .. autoclass:: flask.blueprints.BlueprintSetupState
    :members:
@@ -596,7 +605,7 @@ This specifies that ``/users/`` will be the URL for page one and
 ``/users/page/N`` will be the URL for page ``N``.
 
 If a URL contains a default value, it will be redirected to its simpler
-form with a 308 redirect. In the above example, ``/users/page/1`` will
+form with a 301 redirect. In the above example, ``/users/page/1`` will
 be redirected to ``/users/``. If your route handles ``GET`` and ``POST``
 requests, make sure the default route only handles ``GET``, as redirects
 can't preserve form data. ::

docs/appcontext.rst

@@ -1,63 +1,74 @@
-The App and Request Context
-===========================
+.. currentmodule:: flask
 
-The context keeps track of data and objects during a request, CLI command, or
-other activity. Rather than passing this data around to every function, the
-:data:`.current_app`, :data:`.g`, :data:`.request`, and :data:`.session` proxies
-are accessed instead.
+The Application Context
+=======================
 
-When handling a request, the context is referred to as the "request context"
-because it contains request data in addition to application data. Otherwise,
-such as during a CLI command, it is referred to as the "app context". During an
-app context, :data:`.current_app` and :data:`.g` are available, while during a
-request context :data:`.request` and :data:`.session` are also available.
+The application context keeps track of the application-level data during
+a request, CLI command, or other activity. Rather than passing the
+application around to each function, the :data:`current_app` and
+:data:`g` proxies are accessed instead.
 
+This is similar to :doc:`/reqcontext`, which keeps track of
+request-level data during a request. A corresponding application context
+is pushed when a request context is pushed.
 
 Purpose of the Context
 ----------------------
 
-The context and proxies help solve two development issues: circular imports, and
-passing around global data during a request.
+The :class:`Flask` application object has attributes, such as
+:attr:`~Flask.config`, that are useful to access within views and
+:doc:`CLI commands </cli>`. However, importing the ``app`` instance
+within the modules in your project is prone to circular import issues.
+When using the :doc:`app factory pattern </patterns/appfactories>` or
+writing reusable :doc:`blueprints </blueprints>` or
+:doc:`extensions </extensions>` there won't be an ``app`` instance to
+import at all.
 
-The :class:`.Flask` application object has attributes, such as
-:attr:`~.Flask.config`, that are useful to access within views and other
-functions. However, importing the ``app`` instance within the modules in your
-project is prone to circular import issues. When using the
-:doc:`app factory pattern </patterns/appfactories>` or writing reusable
-:doc:`blueprints </blueprints>` or :doc:`extensions </extensions>` there won't
-be an ``app`` instance to import at all.
+Flask solves this issue with the *application context*. Rather than
+referring to an ``app`` directly, you use the :data:`current_app`
+proxy, which points to the application handling the current activity.
 
-When the application handles a request, it creates a :class:`.Request` object.
-Because a *worker* handles only one request at a time, the request data can be
-considered global to that worker during that request. Passing it as an argument
-through every function during the request becomes verbose and redundant.
+Flask automatically *pushes* an application context when handling a
+request. View functions, error handlers, and other functions that run
+during a request will have access to :data:`current_app`.
 
-Flask solves these issues with the *active context* pattern. Rather than
-importing an ``app`` directly, or having to pass it and the request through to
-every single function, you import and access the proxies, which point to the
-currently active application and request data. This is sometimes referred to
-as "context local" data.
+Flask will also automatically push an app context when running CLI
+commands registered with :attr:`Flask.cli` using ``@app.cli.command()``.
 
 
-Context During Setup
---------------------
+Lifetime of the Context
+-----------------------
 
-If you try to access :data:`.current_app`, :data:`.g`, or anything that uses it,
-outside an app context, you'll get this error message:
+The application context is created and destroyed as necessary. When a
+Flask application begins handling a request, it pushes an application
+context and a :doc:`request context </reqcontext>`. When the request
+ends it pops the request context then the application context.
+Typically, an application context will have the same lifetime as a
+request.
+
+See :doc:`/reqcontext` for more information about how the contexts work
+and the full life cycle of a request.
+
+
+Manually Push a Context
+-----------------------
+
+If you try to access :data:`current_app`, or anything that uses it,
+outside an application context, you'll get this error message:
 
 .. code-block:: pytb
 
     RuntimeError: Working outside of application context.
 
-    Attempted to use functionality that expected a current application to be
-    set. To solve this, set up an app context using 'with app.app_context()'.
-    See the documentation on app context for more information.
+    This typically means that you attempted to use functionality that
+    needed to interface with the current application object in some way.
+    To solve this, set up an application context with app.app_context().
 
 If you see that error while configuring your application, such as when
-initializing an extension, you can push a context manually since you have direct
-access to the ``app``. Use :meth:`.Flask.app_context` in a ``with`` block.
-
-.. code-block:: python
+initializing an extension, you can push a context manually since you
+have direct access to the ``app``. Use :meth:`~Flask.app_context` in a
+``with`` block, and everything that runs in the block will have access
+to :data:`current_app`. ::
 
     def create_app():
         app = Flask(__name__)
@@ -67,121 +78,70 @@ access to the ``app``. Use :meth:`.Flask.app_context` in a ``with`` block.
 
         return app
 
-If you see that error somewhere else in your code not related to setting up the
-application, it most likely indicates that you should move that code into a view
-function or CLI command.
+If you see that error somewhere else in your code not related to
+configuring the application, it most likely indicates that you should
+move that code into a view function or CLI command.
 
 
-Context During Testing
-----------------------
+Storing Data
+------------
 
-See :doc:`/testing` for detailed information about managing the context during
-tests.
+The application context is a good place to store common data during a
+request or CLI command. Flask provides the :data:`g object <g>` for this
+purpose. It is a simple namespace object that has the same lifetime as
+an application context.
 
-If you try to access :data:`.request`, :data:`.session`, or anything that uses
-it, outside a request context, you'll get this error message:
+.. note::
+    The ``g`` name stands for "global", but that is referring to the
+    data being global *within a context*. The data on ``g`` is lost
+    after the context ends, and it is not an appropriate place to store
+    data between requests. Use the :data:`session` or a database to
+    store data across requests.
 
-.. code-block:: pytb
+A common use for :data:`g` is to manage resources during a request.
 
-    RuntimeError: Working outside of request context.
+1.  ``get_X()`` creates resource ``X`` if it does not exist, caching it
+    as ``g.X``.
+2.  ``teardown_X()`` closes or otherwise deallocates the resource if it
+    exists. It is registered as a :meth:`~Flask.teardown_appcontext`
+    handler.
 
-    Attempted to use functionality that expected an active HTTP request. See the
-    documentation on request context for more information.
+For example, you can manage a database connection using this pattern::
 
-This will probably only happen during tests. If you see that error somewhere
-else in your code not related to testing, it most likely indicates that you
-should move that code into a view function.
+    from flask import g
 
-The primary way to solve this is to use :meth:`.Flask.test_client` to simulate
-a full request.
+    def get_db():
+        if 'db' not in g:
+            g.db = connect_to_database()
 
-If you only want to unit test one function, rather than a full request, use
-:meth:`.Flask.test_request_context` in a ``with`` block.
+        return g.db
 
-.. code-block:: python
+    @app.teardown_appcontext
+    def teardown_db(exception):
+        db = g.pop('db', None)
 
-    def generate_report(year):
-        format = request.args.get("format")
-        ...
+        if db is not None:
+            db.close()
 
-    with app.test_request_context(
-        "/make_report/2017", query_string={"format": "short"}
-    ):
-        generate_report()
+During a request, every call to ``get_db()`` will return the same
+connection, and it will be closed automatically at the end of the
+request.
+
+You can use :class:`~werkzeug.local.LocalProxy` to make a new context
+local from ``get_db()``::
+
+    from werkzeug.local import LocalProxy
+    db = LocalProxy(get_db)
+
+Accessing ``db`` will call ``get_db`` internally, in the same way that
+:data:`current_app` works.
 
 
-.. _context-visibility:
+Events and Signals
+------------------
 
-Visibility of the Context
--------------------------
+The application will call functions registered with :meth:`~Flask.teardown_appcontext`
+when the application context is popped.
 
-The context will have the same lifetime as an activity, such as a request, CLI
-command, or ``with`` block. Various callbacks and signals registered with the
-app will be run during the context.
-
-When a Flask application handles a request, it pushes a request context
-to set the active application and request data. When it handles a CLI command,
-it pushes an app context to set the active application. When the activity ends,
-it pops that context. Proxy objects like :data:`.request`, :data:`.session`,
-:data:`.g`, and :data:`.current_app`, are accessible while the context is pushed
-and active, and are not accessible after the context is popped.
-
-The context is unique to each thread (or other worker type). The proxies cannot
-be passed to another worker, which has a different context space and will not
-know about the active context in the parent's space.
-
-Besides being scoped to each worker, the proxy object has a separate type and
-identity than the proxied real object. In some cases you'll need access to the
-real object, rather than the proxy. Use the
-:meth:`~.LocalProxy._get_current_object` method in those cases.
-
-.. code-block:: python
-
-    app = current_app._get_current_object()
-    my_signal.send(app)
-
-
-Lifecycle of the Context
-------------------------
-
-Flask dispatches a request in multiple stages which can affect the request,
-response, and how errors are handled. See :doc:`/lifecycle` for a list of all
-the steps, callbacks, and signals during each request. The following are the
-steps directly related to the context.
-
--   The app context is pushed, the proxies are available.
--   The :data:`.appcontext_pushed` signal is sent.
--   The request is dispatched.
--   Any :meth:`.Flask.teardown_request` decorated functions are called.
--   The :data:`.request_tearing_down` signal is sent.
--   Any :meth:`.Flask.teardown_appcontext` decorated functions are called.
--   The :data:`.appcontext_tearing_down` signal is sent.
--   The app context is popped, the proxies are no longer available.
--   The :data:`.appcontext_popped` signal is sent.
-
-The teardown callbacks are called by the context when it is popped. They are
-called even if there is an unhandled exception during dispatch. They may be
-called multiple times in some test scenarios. This means there is no guarantee
-that any other parts of the request dispatch have run. Be sure to write these
-functions in a way that does not depend on other callbacks. All callbacks are
-called even if any raise an error.
-
-
-How the Context Works
----------------------
-
-Context locals are implemented using Python's :mod:`contextvars` and Werkzeug's
-:class:`~werkzeug.local.LocalProxy`. Python's contextvars are a low level
-structure to manage data local to a thread or coroutine. ``LocalProxy`` wraps
-the contextvar so that access to any attributes and methods is forwarded to the
-object stored in the contextvar.
-
-The context is tracked like a stack, with the active context at the top of the
-stack. Flask manages pushing and popping contexts during requests, CLI commands,
-testing, ``with`` blocks, etc. The proxies access attributes on the active
-context.
-
-Because it is a stack, other contexts may be pushed to change the proxies during
-an already active context. This is not a common pattern, but can be used in
-advanced use cases. For example, a Flask application can be used as WSGI
-middleware, calling another wrapped Flask app from a view.
+The following signals are sent: :data:`appcontext_pushed`,
+:data:`appcontext_tearing_down`, and :data:`appcontext_popped`.

docs/async-await.rst

@@ -23,6 +23,18 @@ method in views that inherit from the :class:`flask.views.View` class, as
 well as all the HTTP method handlers in views that inherit from the
 :class:`flask.views.MethodView` class.
 
+.. admonition:: Using ``async`` on Windows on Python 3.8
+
+    Python 3.8 has a bug related to asyncio on Windows. If you encounter
+    something like ``ValueError: set_wakeup_fd only works in main thread``,
+    please upgrade to Python 3.9.
+
+.. admonition:: Using ``async`` with greenlet
+
+    When using gevent or eventlet to serve an application or patch the
+    runtime, greenlet>=1.0 is required. When using PyPy, PyPy>=7.3.7 is
+    required.
+
 
 Performance
 -----------
@@ -72,15 +84,15 @@ Flask based on the `ASGI`_ standard instead of WSGI. This allows it to
 handle many concurrent requests, long running requests, and websockets
 without requiring multiple worker processes or threads.
 
-It has also already been possible to :doc:`run Flask with Gevent </gevent>` to
-get many of the benefits of async request handling. Gevent patches low-level
-Python functions to accomplish this, whereas ``async``/``await`` and ASGI use
-standard, modern Python capabilities. Deciding whether you should use gevent
-with Flask, or Quart, or something else is ultimately up to understanding the
-specific needs of your project.
+It has also already been possible to run Flask with Gevent or Eventlet
+to get many of the benefits of async request handling. These libraries
+patch low-level Python functions to accomplish this, whereas ``async``/
+``await`` and ASGI use standard, modern Python capabilities. Deciding
+whether you should use Flask, Quart, or something else is ultimately up
+to understanding the specific needs of your project.
 
-.. _Quart: https://quart.palletsprojects.com
-.. _ASGI: https://asgi.readthedocs.io
+.. _Quart: https://github.com/pallets/quart
+.. _ASGI: https://asgi.readthedocs.io/en/latest/
 
 
 Extensions
@@ -114,6 +126,6 @@ implemented async support, or make a feature request or PR to them.
 Other event loops
 -----------------
 
-At the moment Flask only supports :mod:`asyncio`. It's possible to override
-:meth:`flask.Flask.ensure_sync` to change how async functions are wrapped to use
-a different library. See :ref:`gevent-asyncio` for an example.
+At the moment Flask only supports :mod:`asyncio`. It's possible to
+override :meth:`flask.Flask.ensure_sync` to change how async functions
+are wrapped to use a different library.

docs/conf.py

@@ -11,23 +11,16 @@ release, version = get_version("Flask")
 
 # General --------------------------------------------------------------
 
-default_role = "code"
+master_doc = "index"
 extensions = [
     "sphinx.ext.autodoc",
-    "sphinx.ext.extlinks",
     "sphinx.ext.intersphinx",
     "sphinxcontrib.log_cabinet",
-    "sphinx_tabs.tabs",
     "pallets_sphinx_themes",
+    "sphinx_issues",
+    "sphinx_tabs.tabs",
 ]
-autodoc_member_order = "bysource"
 autodoc_typehints = "description"
-autodoc_preserve_defaults = True
-extlinks = {
-    "issue": ("https://github.com/pallets/flask/issues/%s", "#%s"),
-    "pr": ("https://github.com/pallets/flask/pull/%s", "#%s"),
-    "ghsa": ("https://github.com/pallets/flask/security/advisories/GHSA-%s", "GHSA-%s"),
-}
 intersphinx_mapping = {
     "python": ("https://docs.python.org/3/", None),
     "werkzeug": ("https://werkzeug.palletsprojects.com/", None),
@@ -38,6 +31,7 @@ intersphinx_mapping = {
     "wtforms": ("https://wtforms.readthedocs.io/", None),
     "blinker": ("https://blinker.readthedocs.io/", None),
 }
+issues_github_path = "pallets/flask"
 
 # HTML -----------------------------------------------------------------
 
@@ -58,13 +52,14 @@ html_sidebars = {
 }
 singlehtml_sidebars = {"index": ["project.html", "localtoc.html", "ethicalads.html"]}
 html_static_path = ["_static"]
-html_favicon = "_static/flask-icon.svg"
-html_logo = "_static/flask-logo.svg"
+html_favicon = "_static/shortcut-icon.png"
+html_logo = "_static/flask-vertical.png"
 html_title = f"Flask Documentation ({version})"
 html_show_sourcelink = False
 
-gettext_uuid = True
-gettext_compact = False
+# LaTeX ----------------------------------------------------------------
+
+latex_documents = [(master_doc, f"Flask-{version}.tex", html_title, author, "manual")]
 
 # Local Extensions -----------------------------------------------------
 

docs/config.rst

@@ -79,7 +79,7 @@ The following configuration values are used internally by Flask:
 
 .. py:data:: TESTING
 
-    Enable testing mode. Exceptions are propagated rather than handled by
+    Enable testing mode. Exceptions are propagated rather than handled by the
     the app's error handlers. Extensions may also change their behavior to
     facilitate easier testing. You should enable this in your own tests.
 
@@ -125,25 +125,6 @@ The following configuration values are used internally by Flask:
 
     Default: ``None``
 
-.. py:data:: SECRET_KEY_FALLBACKS
-
-    A list of old secret keys that can still be used for unsigning. This allows
-    a project to implement key rotation without invalidating active sessions or
-    other recently-signed secrets.
-
-    Keys should be removed after an appropriate period of time, as checking each
-    additional key adds some overhead.
-
-    Order should not matter, but the default implementation will test the last
-    key in the list first, so it might make sense to order oldest to newest.
-
-    Flask's built-in secure cookie session supports this. Extensions that use
-    :data:`SECRET_KEY` may not support this yet.
-
-    Default: ``None``
-
-    .. versionadded:: 3.1
-
 .. py:data:: SESSION_COOKIE_NAME
 
     The name of the session cookie. Can be changed in case you already have a
@@ -161,12 +142,6 @@ The following configuration values are used internally by Flask:
 
     Default: ``None``
 
-    .. warning::
-        If this is changed after the browser created a cookie is created with
-        one setting, it may result in another being created. Browsers may send
-        send both in an undefined order. In that case, you may want to change
-        :data:`SESSION_COOKIE_NAME` as well or otherwise invalidate old sessions.
-
     .. versionchanged:: 2.3
         Not set by default, does not fall back to ``SERVER_NAME``.
 
@@ -192,23 +167,6 @@ The following configuration values are used internally by Flask:
 
     Default: ``False``
 
-.. py:data:: SESSION_COOKIE_PARTITIONED
-
-    Browsers will send cookies based on the top-level document's domain, rather
-    than only the domain of the document setting the cookie. This prevents third
-    party cookies set in iframes from "leaking" between separate sites.
-
-    Browsers are beginning to disallow non-partitioned third party cookies, so
-    you need to mark your cookies partitioned if you expect them to work in such
-    embedded situations.
-
-    Enabling this implicitly enables :data:`SESSION_COOKIE_SECURE` as well, as
-    it is only valid when served over HTTPS.
-
-    Default: ``False``
-
-    .. versionadded:: 3.1
-
 .. py:data:: SESSION_COOKIE_SAMESITE
 
     Restrict how cookies are sent with requests from external sites. Can
@@ -261,40 +219,16 @@ The following configuration values are used internally by Flask:
 
     Default: ``None``
 
-.. py:data:: TRUSTED_HOSTS
-
-    Validate :attr:`.Request.host` and other attributes that use it against
-    these trusted values. Raise a :exc:`~werkzeug.exceptions.SecurityError` if
-    the host is invalid, which results in a 400 error. If it is ``None``, all
-    hosts are valid. Each value is either an exact match, or can start with
-    a dot ``.`` to match any subdomain.
-
-    Validation is done during routing against this value. ``before_request`` and
-    ``after_request`` callbacks will still be called.
-
-    Default: ``None``
-
-    .. versionadded:: 3.1
-
 .. py:data:: SERVER_NAME
 
-    Inform the application what host and port it is bound to.
+    Inform the application what host and port it is bound to. Required
+    for subdomain route matching support.
 
-    Must be set if ``subdomain_matching`` is enabled, to be able to extract the
-    subdomain from the request.
-
-    Must be set for ``url_for`` to generate external URLs outside of a
-    request context.
+    If set, ``url_for`` can generate external URLs with only an application
+    context instead of a request context.
 
     Default: ``None``
 
-    .. versionchanged:: 3.1
-        Does not restrict requests to only this domain, for both
-        ``subdomain_matching`` and ``host_matching``.
-
-    .. versionchanged:: 1.0
-        Does not implicitly enable ``subdomain_matching``.
-
     .. versionchanged:: 2.3
         Does not affect ``SESSION_COOKIE_DOMAIN``.
 
@@ -319,54 +253,12 @@ The following configuration values are used internally by Flask:
 
 .. py:data:: MAX_CONTENT_LENGTH
 
-    The maximum number of bytes that will be read during this request. If
-    this limit is exceeded, a 413 :exc:`~werkzeug.exceptions.RequestEntityTooLarge`
-    error is raised. If it is set to ``None``, no limit is enforced at the
-    Flask application level. However, if it is ``None`` and the request has no
-    ``Content-Length`` header and the WSGI server does not indicate that it
-    terminates the stream, then no data is read to avoid an infinite stream.
-
-    Each request defaults to this config. It can be set on a specific
-    :attr:`.Request.max_content_length` to apply the limit to that specific
-    view. This should be set appropriately based on an application's or view's
-    specific needs.
+    Don't read more than this many bytes from the incoming request data. If not
+    set and the request does not specify a ``CONTENT_LENGTH``, no data will be
+    read for security.
 
     Default: ``None``
 
-    .. versionadded:: 0.6
-
-.. py:data:: MAX_FORM_MEMORY_SIZE
-
-    The maximum size in bytes any non-file form field may be in a
-    ``multipart/form-data`` body. If this limit is exceeded, a 413
-    :exc:`~werkzeug.exceptions.RequestEntityTooLarge` error is raised. If it is
-    set to ``None``, no limit is enforced at the Flask application level.
-
-    Each request defaults to this config. It can be set on a specific
-    :attr:`.Request.max_form_memory_parts` to apply the limit to that specific
-    view. This should be set appropriately based on an application's or view's
-    specific needs.
-
-    Default: ``500_000``
-
-    .. versionadded:: 3.1
-
-.. py:data:: MAX_FORM_PARTS
-
-    The maximum number of fields that may be present in a
-    ``multipart/form-data`` body. If this limit is exceeded, a 413
-    :exc:`~werkzeug.exceptions.RequestEntityTooLarge` error is raised. If it
-    is set to ``None``, no limit is enforced at the Flask application level.
-
-    Each request defaults to this config. It can be set on a specific
-    :attr:`.Request.max_form_parts` to apply the limit to that specific view.
-    This should be set appropriately based on an application's or view's
-    specific needs.
-
-    Default: ``1_000``
-
-    .. versionadded:: 3.1
-
 .. py:data:: TEMPLATES_AUTO_RELOAD
 
     Reload templates when they are changed. If not set, it will be enabled in
@@ -388,12 +280,6 @@ The following configuration values are used internally by Flask:
     ``4093``. Larger cookies may be silently ignored by browsers. Set to
     ``0`` to disable the warning.
 
-.. py:data:: PROVIDE_AUTOMATIC_OPTIONS
-
-    Set to ``False`` to disable the automatic addition of OPTIONS
-    responses. This can be overridden per route by altering the
-    ``provide_automatic_options`` attribute.
-
 .. versionadded:: 0.4
    ``LOGGER_NAME``
 
@@ -445,10 +331,6 @@ The following configuration values are used internally by Flask:
 .. versionchanged:: 2.3
     ``ENV`` was removed.
 
-.. versionadded:: 3.1
-    Added :data:`PROVIDE_AUTOMATIC_OPTIONS` to control the default
-    addition of autogenerated OPTIONS responses.
-
 
 Configuring from Python Files
 -----------------------------

docs/contributing.rst

@@ -1,8 +1 @@
-Contributing
-============
-
-See the Pallets `detailed contributing documentation <contrib_>`_ for many ways
-to contribute, including reporting issues, requesting features, asking or
-answering questions, and making PRs.
-
-.. _contrib: https://palletsprojects.com/contributing/
+.. include:: ../CONTRIBUTING.rst

docs/deploying/asgi.rst

@@ -20,7 +20,7 @@ wrapping the Flask app,
     asgi_app = WsgiToAsgi(app)
 
 and then serving the ``asgi_app`` with the ASGI server, e.g. using
-`Hypercorn <https://github.com/pgjones/hypercorn>`_,
+`Hypercorn <https://gitlab.com/pgjones/hypercorn>`_,
 
 .. sourcecode:: text
 

docs/deploying/eventlet.rst

@@ -1,8 +1,80 @@
-:orphan:
-
 eventlet
 ========
 
-`Eventlet is no longer maintained.`__ Use :doc:`/deploying/gevent` instead.
+Prefer using :doc:`gunicorn` with eventlet workers rather than using
+`eventlet`_ directly. Gunicorn provides a much more configurable and
+production-tested server.
 
-__ https://eventlet.readthedocs.io
+`eventlet`_ allows writing asynchronous, coroutine-based code that looks
+like standard synchronous Python. It uses `greenlet`_ to enable task
+switching without writing ``async/await`` or using ``asyncio``.
+
+:doc:`gevent` is another library that does the same thing. Certain
+dependencies you have, or other considerations, may affect which of the
+two you choose to use.
+
+eventlet provides a WSGI server that can handle many connections at once
+instead of one per worker process. You must actually use eventlet in
+your own code to see any benefit to using the server.
+
+.. _eventlet: https://eventlet.net/
+.. _greenlet: https://greenlet.readthedocs.io/en/latest/
+
+
+Installing
+----------
+
+When using eventlet, greenlet>=1.0 is required, otherwise context locals
+such as ``request`` will not work as expected. When using PyPy,
+PyPy>=7.3.7 is required.
+
+Create a virtualenv, install your application, then install
+``eventlet``.
+
+.. code-block:: text
+
+    $ cd hello-app
+    $ python -m venv .venv
+    $ . .venv/bin/activate
+    $ pip install .  # install your application
+    $ pip install eventlet
+
+
+Running
+-------
+
+To use eventlet to serve your application, write a script that imports
+its ``wsgi.server``, as well as your app or app factory.
+
+.. code-block:: python
+    :caption: ``wsgi.py``
+
+    import eventlet
+    from eventlet import wsgi
+    from hello import create_app
+
+    app = create_app()
+    wsgi.server(eventlet.listen(("127.0.0.1", 8000)), app)
+
+.. code-block:: text
+
+    $ python wsgi.py
+    (x) wsgi starting up on http://127.0.0.1:8000
+
+
+Binding Externally
+------------------
+
+eventlet should not be run as root because it would cause your
+application code to run as root, which is not secure. However, this
+means it will not be possible to bind to port 80 or 443. Instead, a
+reverse proxy such as :doc:`nginx` or :doc:`apache-httpd` should be used
+in front of eventlet.
+
+You can bind to all external IPs on a non-privileged port by using
+``0.0.0.0`` in the server arguments shown in the previous section.
+Don't do this when using a reverse proxy setup, otherwise it will be
+possible to bypass the proxy.
+
+``0.0.0.0`` is not a valid address to navigate to, you'd use a specific
+IP address in your browser.

docs/deploying/gevent.rst

@@ -7,12 +7,15 @@ configurable and production-tested servers.
 
 `gevent`_ allows writing asynchronous, coroutine-based code that looks
 like standard synchronous Python. It uses `greenlet`_ to enable task
-switching without writing ``async/await`` or using ``asyncio``. This is
-not the same as Python's ``async/await``, or the ASGI server spec.
+switching without writing ``async/await`` or using ``asyncio``.
+
+:doc:`eventlet` is another library that does the same thing. Certain
+dependencies you have, or other considerations, may affect which of the
+two you choose to use.
 
 gevent provides a WSGI server that can handle many connections at once
-instead of one per worker process. See :doc:`/gevent` for more
-information about enabling it in your application.
+instead of one per worker process. You must actually use gevent in your
+own code to see any benefit to using the server.
 
 .. _gevent: https://www.gevent.org/
 .. _greenlet: https://greenlet.readthedocs.io/en/latest/
@@ -21,7 +24,8 @@ information about enabling it in your application.
 Installing
 ----------
 
-When using gevent, greenlet>=1.0 is required. When using PyPy,
+When using gevent, greenlet>=1.0 is required, otherwise context locals
+such as ``request`` will not work as expected. When using PyPy,
 PyPy>=7.3.7 is required.
 
 Create a virtualenv, install your application, then install ``gevent``.

docs/deploying/gunicorn.rst

@@ -8,7 +8,7 @@ multiple worker implementations for performance tuning.
 *   It does not support Windows (but does run on WSL).
 *   It is easy to install as it does not require additional dependencies
     or compilation.
-*   It has built-in async worker support using gevent.
+*   It has built-in async worker support using gevent or eventlet.
 
 This page outlines the basics of running Gunicorn. Be sure to read its
 `documentation`_ and use ``gunicorn --help`` to understand what features
@@ -93,19 +93,20 @@ otherwise it will be possible to bypass the proxy.
 IP address in your browser.
 
 
-Async with gevent
------------------
+Async with gevent or eventlet
+-----------------------------
 
-The default sync worker is appropriate for most use cases. If you need numerous,
-long running, concurrent connections, Gunicorn provides an asynchronous worker
-using `gevent`_. This is not the same as Python's ``async/await``, or the ASGI
-server spec. See :doc:`/gevent` for more information about enabling it in your
-application.
+The default sync worker is appropriate for many use cases. If you need
+asynchronous support, Gunicorn provides workers using either `gevent`_
+or `eventlet`_. This is not the same as Python's ``async/await``, or the
+ASGI server spec. You must actually use gevent/eventlet in your own code
+to see any benefit to using the workers.
 
-.. _gevent: https://www.gevent.org/
+When using either gevent or eventlet, greenlet>=1.0 is required,
+otherwise context locals such as ``request`` will not work as expected.
+When using PyPy, PyPy>=7.3.7 is required.
 
-When using gevent, greenlet>=1.0 is required. When using PyPy, PyPy>=7.3.7 is
-required.
+To use gevent:
 
 .. code-block:: text
 
@@ -114,3 +115,16 @@ required.
     Listening at: http://127.0.0.1:8000 (x)
     Using worker: gevent
     Booting worker with pid: x
+
+To use eventlet:
+
+.. code-block:: text
+
+    $ gunicorn -k eventlet 'hello:create_app()'
+    Starting gunicorn 20.1.0
+    Listening at: http://127.0.0.1:8000 (x)
+    Using worker: eventlet
+    Booting worker with pid: x
+
+.. _gevent: https://www.gevent.org/
+.. _eventlet: https://eventlet.net/

docs/deploying/index.rst

@@ -36,6 +36,7 @@ discusses platforms that can manage this for you.
     mod_wsgi
     uwsgi
     gevent
+    eventlet
     asgi
 
 WSGI servers have HTTP servers built-in. However, a dedicated HTTP

docs/deploying/uwsgi.rst

@@ -119,16 +119,15 @@ IP address in your browser.
 Async with gevent
 -----------------
 
-The default sync worker is appropriate for most use cases. If you need numerous,
-long running, concurrent connections, uWSGI provides an asynchronous worker
-using `gevent`_. This is not the same as Python's ``async/await``, or the ASGI
-server spec. See :doc:`/gevent` for more information about enabling it in your
-application.
+The default sync worker is appropriate for many use cases. If you need
+asynchronous support, uWSGI provides a `gevent`_ worker. This is not the
+same as Python's ``async/await``, or the ASGI server spec. You must
+actually use gevent in your own code to see any benefit to using the
+worker.
 
-.. _gevent: https://www.gevent.org/
-
-When using gevent, greenlet>=1.0 is required. When using PyPy, PyPy>=7.3.7 is
-required.
+When using gevent, greenlet>=1.0 is required, otherwise context locals
+such as ``request`` will not work as expected. When using PyPy,
+PyPy>=7.3.7 is required.
 
 .. code-block:: text
 
@@ -141,3 +140,6 @@ required.
     spawned uWSGI worker 1 (pid: x, cores: 100)
     spawned uWSGI http 1 (pid: x)
     *** running gevent loop engine [addr:x] ***
+
+
+.. _gevent: https://www.gevent.org/

docs/deploying/waitress.rst

@@ -68,7 +68,7 @@ reverse proxy such as :doc:`nginx` or :doc:`apache-httpd` should be used
 in front of Waitress.
 
 You can bind to all external IPs on a non-privileged port by not
-specifying the ``--host`` option. Don't do this when using a reverse
+specifying the ``--host`` option. Don't do this when using a revers
 proxy setup, otherwise it will be possible to bypass the proxy.
 
 ``0.0.0.0`` is not a valid address to navigate to, you'd use a specific

docs/design.rst

@@ -96,10 +96,10 @@ is ambiguous.
 One Template Engine
 -------------------
 
-Flask decides on one template engine: Jinja.  Why doesn't Flask have a
+Flask decides on one template engine: Jinja2.  Why doesn't Flask have a
 pluggable template engine interface?  You can obviously use a different
-template engine, but Flask will still configure Jinja for you.  While
-that limitation that Jinja is *always* configured will probably go away,
+template engine, but Flask will still configure Jinja2 for you.  While
+that limitation that Jinja2 is *always* configured will probably go away,
 the decision to bundle one template engine and use that will not.
 
 Template engines are like programming languages and each of those engines
@@ -107,7 +107,7 @@ has a certain understanding about how things work.  On the surface they
 all work the same: you tell the engine to evaluate a template with a set
 of variables and take the return value as string.
 
-But that's about where similarities end. Jinja for example has an
+But that's about where similarities end. Jinja2 for example has an
 extensive filter system, a certain way to do template inheritance,
 support for reusable blocks (macros) that can be used from inside
 templates and also from Python code, supports iterative template
@@ -118,8 +118,8 @@ other hand treats templates similar to Python modules.
 
 When it comes to connecting a template engine with an application or
 framework there is more than just rendering templates.  For instance,
-Flask uses Jinja's extensive autoescaping support.  Also it provides
-ways to access macros from Jinja templates.
+Flask uses Jinja2's extensive autoescaping support.  Also it provides
+ways to access macros from Jinja2 templates.
 
 A template abstraction layer that would not take the unique features of
 the template engines away is a science on its own and a too large
@@ -150,7 +150,7 @@ authentication technologies, and more. Flask may be "micro", but it's ready for
 production use on a variety of needs.
 
 Why does Flask call itself a microframework and yet it depends on two
-libraries (namely Werkzeug and Jinja).  Why shouldn't it?  If we look
+libraries (namely Werkzeug and Jinja2).  Why shouldn't it?  If we look
 over to the Ruby side of web development there we have a protocol very
 similar to WSGI.  Just that it's called Rack there, but besides that it
 looks very much like a WSGI rendition for Ruby.  But nearly all
@@ -169,20 +169,19 @@ infrastructure, packages with dependencies are no longer an issue and
 there are very few reasons against having libraries that depend on others.
 
 
-Context Locals
---------------
+Thread Locals
+-------------
 
-Flask uses special context locals and proxies to provide access to the
-current app and request data to any code running during a request, CLI command,
-etc. Context locals are specific to the worker handling the activity, such as a
-thread, process, coroutine, or greenlet.
+Flask uses thread local objects (context local objects in fact, they
+support greenlet contexts as well) for request, session and an extra
+object you can put your own things on (:data:`~flask.g`).  Why is that and
+isn't that a bad idea?
 
-The context and proxies help solve two development issues: circular imports, and
-passing around global data. :data:`.current_app` can be used to access the
-application object without needing to import the app object directly, avoiding
-circular import issues. :data:`.request`, :data:`.session`, and :data:`.g` can
-be imported to access the current data for the request, rather than needing to
-pass them as arguments through every single function in your project.
+Yes it is usually not such a bright idea to use thread locals.  They cause
+troubles for servers that are not based on the concept of threads and make
+large applications harder to maintain.  However Flask is just not designed
+for large applications or asynchronous servers.  Flask wants to make it
+quick and easy to write a traditional web application.
 
 
 Async/await and ASGI support
@@ -209,7 +208,7 @@ What Flask is, What Flask is Not
 
 Flask will never have a database layer.  It will not have a form library
 or anything else in that direction.  Flask itself just bridges to Werkzeug
-to implement a proper WSGI application and to Jinja to handle templating.
+to implement a proper WSGI application and to Jinja2 to handle templating.
 It also binds to a few common standard library packages such as logging.
 Everything else is up for extensions.
 

docs/extensiondev.rst

@@ -67,7 +67,7 @@ application instance.
 It is important that the app is not stored on the extension, don't do
 ``self.app = app``. The only time the extension should have direct
 access to an app is during ``init_app``, otherwise it should use
-:data:`.current_app`.
+:data:`current_app`.
 
 This allows the extension to support the application factory pattern,
 avoids circular import issues when importing the extension instance
@@ -105,7 +105,7 @@ during an extension's ``init_app`` method.
 A common pattern is to use :meth:`~Flask.before_request` to initialize
 some data or a connection at the beginning of each request, then
 :meth:`~Flask.teardown_request` to clean it up at the end. This can be
-stored on :data:`.g`, discussed more below.
+stored on :data:`g`, discussed more below.
 
 A more lazy approach is to provide a method that initializes and caches
 the data or connection. For example, a ``ext.get_db`` method could
@@ -179,12 +179,13 @@ name as a prefix, or as a namespace.
     g._hello = SimpleNamespace()
     g._hello.user_id = 2
 
-The data in ``g`` lasts for an application context. An application context is
-active during a request, CLI command, or ``with app.app_context()`` block. If
-you're storing something that should be closed, use
-:meth:`~flask.Flask.teardown_appcontext` to ensure that it gets closed when the
-app context ends. If it should only be valid during a request, or would not be
-used in the CLI outside a request, use :meth:`~flask.Flask.teardown_request`.
+The data in ``g`` lasts for an application context. An application
+context is active when a request context is, or when a CLI command is
+run. If you're storing something that should be closed, use
+:meth:`~flask.Flask.teardown_appcontext` to ensure that it gets closed
+when the application context ends. If it should only be valid during a
+request, or would not be used in the CLI outside a request, use
+:meth:`~flask.Flask.teardown_request`.
 
 
 Views and Models
@@ -293,13 +294,10 @@ ecosystem remain consistent and compatible.
     indicate minimum compatibility support. For example,
     ``sqlalchemy>=1.4``.
 9.  Indicate the versions of Python supported using ``python_requires=">=version"``.
-    Flask and Pallets policy is to support all Python versions that are not
-    within six months of end of life (EOL). See Python's `EOL calendar`_ for
-    timing.
+    Flask itself supports Python >=3.8 as of April 2023, but this will update over time.
 
 .. _PyPI: https://pypi.org/search/?c=Framework+%3A%3A+Flask
 .. _Discord Chat: https://discord.gg/pallets
 .. _GitHub Discussions: https://github.com/pallets/flask/discussions
 .. _Official Pallets Themes: https://pypi.org/project/Pallets-Sphinx-Themes/
 .. _Pallets-Eco: https://github.com/pallets-eco
-.. _EOL calendar: https://devguide.python.org/versions/

docs/gevent.rst

@@ -1,125 +0,0 @@
-Async with Gevent
-=================
-
-`Gevent`_ patches Python's standard library to run within special async workers
-called `greenlets`_. Gevent has existed since long before Python's native
-asyncio was available, and Flask has always worked with it.
-
-.. _gevent: https://www.gevent.org
-.. _greenlets: https://greenlet.readthedocs.io
-
-Gevent is a reliable way to handle numerous, long lived, concurrent connections,
-and to achieve similar capabilities to ASGI and asyncio. This works without
-needing to write ``async def`` or ``await`` anywhere, but relies on gevent and
-greenlet's low level manipulation of the Python interpreter.
-
-Deciding whether you should use gevent with Flask, or `Quart`_, or something
-else, is ultimately up to understanding the specific needs of your project.
-
-.. _quart: https://quart.palletsprojects.com
-
-
-Enabling gevent
----------------
-
-You need to apply gevent's patching as early as possible in your code. This
-enables gevent's underlying event loop and converts many Python internals to run
-inside it. Add the following at the top of your project's module or top
-``__init__.py``:
-
-.. code-block:: python
-
-    import gevent.monkey
-    gevent.monkey.patch_all()
-
-When deploying in production, use :doc:`/deploying/gunicorn` or
-:doc:`/deploying/uwsgi` with a gevent worker, as described on those pages.
-
-To run concurrent tasks within your own code, such as views, use
-|gevent.spawn|_:
-
-.. |gevent.spawn| replace:: ``gevent.spawn()``
-.. _gevent.spawn: https://www.gevent.org/api/gevent.html#gevent.spawn
-
-.. code-block:: python
-
-    @app.post("/send")
-    def send_email():
-        gevent.spawn(email.send, to="example@example.example", text="example")
-        return "Email is being sent."
-
-If you need to access :data:`request` or other Flask context globals within the
-spawned function, decorate the function with :func:`.stream_with_context` or
-:func:`.copy_current_request_context`. Prefer passing the exact data you need
-when spawning the function, rather than using the decorators.
-
-.. note::
-
-    When using gevent, greenlet>=1.0 is required. When using PyPy, PyPy>=7.3.7
-    is required.
-
-
-.. _gevent-asyncio:
-
-Combining with ``async``/``await``
-----------------------------------
-
-Gevent's patching does not interact well with Flask's built-in asyncio support.
-If you want to use Gevent and asyncio in the same app, you'll need to override
-:meth:`flask.Flask.async_to_sync` to run async functions inside gevent.
-
-.. code-block:: python
-
-    import gevent.monkey
-    gevent.monkey.patch_all()
-
-    import asyncio
-    from flask import Flask, request
-
-    loop = asyncio.EventLoop()
-    gevent.spawn(loop.run_forever)
-
-    class GeventFlask(Flask):
-        def async_to_sync(self, func):
-            def run(*args, **kwargs):
-                coro = func(*args, **kwargs)
-                future = asyncio.run_coroutine_threadsafe(coro, loop)
-                return future.result()
-
-            return run
-
-    app = GeventFlask(__name__)
-
-    @app.get("/")
-    async def greet():
-        await asyncio.sleep(1)
-        return f"Hello, {request.args.get("name", "World")}!"
-
-This starts an asyncio event loop in a gevent worker. Async functions are
-scheduled on that event loop. This may still have limitations, and may need to
-be modified further when using other asyncio implementations.
-
-
-libuv
-~~~~~
-
-`libuv`_ is another event loop implementation that `gevent supports`_. There's
-also a project called `uvloop`_ that enables libuv in asyncio. If you want to
-use libuv, use gevent's support, not uvloop. It may be possible to further
-modify the ``async_to_sync`` code from the previous section to work with uvloop,
-but that's not currently known.
-
-.. _libuv: https://libuv.org/
-.. _gevent supports: https://www.gevent.org/loop_impls.html
-.. _uvloop: https://uvloop.readthedocs.io/
-
-To enable gevent's libuv support, add the following at the *very* top of your
-code, before ``gevent.monkey.patch_all()``:
-
-.. code-block:: python
-
-    import gevent
-    gevent.config.loop = "libuv"
-
-    import gevent.monkey
-    gevent.monkey.patch_all()

docs/index.rst

@@ -3,15 +3,10 @@
 Welcome to Flask
 ================
 
-.. image:: _static/flask-name.svg
+.. image:: _static/flask-horizontal.png
     :align: center
-    :height: 200px
 
-Welcome to Flask's documentation. Flask is a lightweight WSGI web application framework.
-It is designed to make getting started quick and easy, with the ability to scale up to
-complex applications.
-
-Get started with :doc:`installation`
+Welcome to Flask's documentation. Get started with :doc:`installation`
 and then get an overview with the :doc:`quickstart`. There is also a
 more detailed :doc:`tutorial/index` that shows how to create a small but
 complete application with Flask. Common patterns are described in the
@@ -52,15 +47,15 @@ community-maintained extensions to add even more functionality.
    views
    lifecycle
    appcontext
+   reqcontext
    blueprints
    extensions
    cli
    server
    shell
    patterns/index
-   web-security
+   security
    deploying/index
-   gevent
    async-await
 
 

docs/installation.rst

@@ -5,7 +5,7 @@ Installation
 Python Version
 --------------
 
-We recommend using the latest version of Python. Flask supports Python 3.10 and newer.
+We recommend using the latest version of Python. Flask supports Python 3.8 and newer.
 
 
 Dependencies
@@ -51,8 +51,9 @@ use them if you install them.
 greenlet
 ~~~~~~~~
 
-You may choose to use :doc:`/gevent` with your application. In this case,
-greenlet>=1.0 is required. When using PyPy, PyPy>=7.3.7 is required.
+You may choose to use gevent or eventlet with your application. In this
+case, greenlet>=1.0 is required. When using PyPy, PyPy>=7.3.7 is
+required.
 
 These are not minimum supported versions, they only indicate the first
 versions that added necessary features. You should use the latest

docs/license.rst

@@ -1,5 +1,4 @@
 BSD-3-Clause License
 ====================
 
-.. literalinclude:: ../LICENSE.txt
-    :language: text
+.. include:: ../LICENSE.rst

docs/lifecycle.rst

@@ -117,12 +117,15 @@ the view function, and pass the return value back to the server. But there are m
 parts that you can use to customize its behavior.
 
 #.  WSGI server calls the Flask object, which calls :meth:`.Flask.wsgi_app`.
-#.  An :class:`.AppContext` object is created. This converts the WSGI ``environ``
-    dict into a :class:`.Request` object.
-#.  The :doc:`app context <appcontext>` is pushed, which makes
-    :data:`.current_app`, :data:`.g`, :data:`.request`, and :data:`.session`
-    available.
+#.  A :class:`.RequestContext` object is created. This converts the WSGI ``environ``
+    dict into a :class:`.Request` object. It also creates an :class:`AppContext` object.
+#.  The :doc:`app context <appcontext>` is pushed, which makes :data:`.current_app` and
+    :data:`.g` available.
 #.  The :data:`.appcontext_pushed` signal is sent.
+#.  The :doc:`request context <reqcontext>` is pushed, which makes :attr:`.request` and
+    :class:`.session` available.
+#.  The session is opened, loading any existing session data using the app's
+    :attr:`~.Flask.session_interface`, an instance of :class:`.SessionInterface`.
 #.  The URL is matched against the URL rules registered with the :meth:`~.Flask.route`
     decorator during application setup. If there is no match, the error - usually a 404,
     405, or redirect - is stored to be handled later.
@@ -138,8 +141,7 @@ parts that you can use to customize its behavior.
     called to handle the error and return a response.
 #.  Whatever returned a response value - a before request function, the view, or an
     error handler, that value is converted to a :class:`.Response` object.
-#.  Any :func:`~.after_this_request` decorated functions are called, which can modify
-    the response object. They are then cleared.
+#.  Any :func:`~.after_this_request` decorated functions are called, then cleared.
 #.  Any :meth:`~.Flask.after_request` decorated functions are called, which can modify
     the response object.
 #.  The session is saved, persisting any modified session data using the app's
@@ -152,19 +154,14 @@ parts that you can use to customize its behavior.
 #.  The response object's status, headers, and body are returned to the WSGI server.
 #.  Any :meth:`~.Flask.teardown_request` decorated functions are called.
 #.  The :data:`.request_tearing_down` signal is sent.
+#.  The request context is popped, :attr:`.request` and :class:`.session` are no longer
+    available.
 #.  Any :meth:`~.Flask.teardown_appcontext` decorated functions are called.
 #.  The :data:`.appcontext_tearing_down` signal is sent.
-#.  The app context is popped, :data:`.current_app`, :data:`.g`, :data:`.request`,
-    and :data:`.session` are no longer available.
+#.  The app context is popped, :data:`.current_app` and :data:`.g` are no longer
+    available.
 #.  The :data:`.appcontext_popped` signal is sent.
 
-When executing a CLI command or plain app context without request data, the same
-order of steps is followed, omitting the steps that refer to the request.
-
-A :class:`Blueprint` can add handlers for these events that are specific to the
-blueprint. The handlers for a blueprint will run if the blueprint
-owns the route that matches the request.
-
 There are even more decorators and customization points than this, but that aren't part
 of every request lifecycle. They're more specific to certain things you might use during
 a request, such as templates, building URLs, or handling JSON data. See the rest of this

docs/logging.rst

@@ -159,7 +159,7 @@ Depending on your project, it may be more useful to configure each logger you
 care about separately, instead of configuring only the root logger. ::
 
     for logger in (
-        logging.getLogger(app.name),
+        app.logger,
         logging.getLogger('sqlalchemy'),
         logging.getLogger('other_package'),
     ):

docs/patterns/appfactories.rst

@@ -99,9 +99,9 @@ to the factory like this:
 
 .. code-block:: text
 
-    $ flask --app 'hello:create_app(local_auth=True)' run
+    $ flask --app hello:create_app(local_auth=True) run
 
-Then the ``create_app`` factory in ``hello`` is called with the keyword
+Then the ``create_app`` factory in ``myapp`` is called with the keyword
 argument ``local_auth=True``. See :doc:`/cli` for more detail.
 
 Factory Improvements

docs/patterns/favicon.rst

@@ -24,11 +24,8 @@ the root path of the domain you either need to configure the web server to
 serve the icon at the root or if you can't do that you're out of luck. If
 however your application is the root you can simply route a redirect::
 
-    app.add_url_rule(
-        "/favicon.ico",
-        endpoint="favicon",
-        redirect_to=url_for("static", filename="favicon.ico"),
-    )
+    app.add_url_rule('/favicon.ico',
+                     redirect_to=url_for('static', filename='favicon.ico'))
 
 If you want to save the extra redirect request you can also write a view
 using :func:`~flask.send_from_directory`::

docs/patterns/javascript.rst

@@ -136,8 +136,7 @@ In general, prefer sending request data as form data, as would be used
 when submitting an HTML form. JSON can represent more complex data, but
 unless you need that it's better to stick with the simpler format. When
 sending JSON data, the ``Content-Type: application/json`` header must be
-sent as well, otherwise Flask will return a 415 Unsupported Media Type
-error.
+sent as well, otherwise Flask will return a 400 error.
 
 .. code-block:: javascript
 
@@ -245,9 +244,8 @@ Receiving JSON in Views
 
 Use the :attr:`~flask.Request.json` property of the
 :data:`~flask.request` object to decode the request's body as JSON. If
-the body is not valid JSON, a 400 Bad Request error will be raised. If
-the ``Content-Type`` header is not set to ``application/json``, a 415
-Unsupported Media Type error will be raised.
+the body is not valid JSON, or the ``Content-Type`` header is not set to
+``application/json``, a 400 Bad Request error will be raised.
 
 .. code-block:: python
 

docs/patterns/mongoengine.rst

@@ -10,7 +10,8 @@ A running MongoDB server and `Flask-MongoEngine`_ are required. ::
     pip install flask-mongoengine
 
 .. _MongoEngine: http://mongoengine.org
-.. _Flask-MongoEngine: https://docs.mongoengine.org/projects/flask-mongoengine/en/latest/
+.. _Flask-MongoEngine: https://flask-mongoengine.readthedocs.io
+
 
 Configuration
 -------------
@@ -79,7 +80,7 @@ Queries
 Use the class ``objects`` attribute to make queries. A keyword argument
 looks for an equal value on the field. ::
 
-    bttf = Movie.objects(title="Back To The Future").get_or_404()
+    bttf = Movies.objects(title="Back To The Future").get_or_404()
 
 Query operators may be used by concatenating them with the field name
 using a double-underscore. ``objects``, and queries returned by

docs/patterns/sqlalchemy.rst

@@ -131,8 +131,9 @@ Here is an example :file:`database.py` module for your application::
     def init_db():
         metadata.create_all(bind=engine)
 
-As in the declarative approach, you need to close the session after each app
-context. Put this into your application module::
+As in the declarative approach, you need to close the session after
+each request or application context shutdown.  Put this into your
+application module::
 
     from yourapplication.database import db_session
 

docs/patterns/sqlite3.rst

@@ -1,9 +1,9 @@
 Using SQLite 3 with Flask
 =========================
 
-You can implement a few functions to work with a SQLite connection during a
-request context. The connection is created the first time it's accessed,
-reused on subsequent access, until it is closed when the request context ends.
+In Flask you can easily implement the opening of database connections on
+demand and closing them when the context dies (usually at the end of the
+request).
 
 Here is a simple example of how you can use SQLite 3 with Flask::
 

docs/patterns/streaming.rst

@@ -8,21 +8,6 @@ roundtrip to the filesystem?
 
 The answer is by using generators and direct responses.
 
-HTTP Response Behavior
-----------------------
-
-**Headers cannot be changed after the streaming response starts.**
-
-When using streaming, it's important to be aware of the order than an HTTP
-response is sent. All headers must be sent first, then the body. More headers
-cannot be sent after the body has begun. Therefore, you must make sure all
-headers are set before starting the response, outside the generator.
-
-In particular, if the generator will access ``session``, be sure to do so in the
-view as well so that the ``Vary: cookie`` header will be set. Do not modify the
-session in the generator, as the ``Set-Cookie`` header will already be sent.
-
-
 Basic Usage
 -----------
 
@@ -44,7 +29,7 @@ debug environments with profilers and other things you might have enabled.
 Streaming from Templates
 ------------------------
 
-The Jinja template engine supports rendering a template piece by
+The Jinja2 template engine supports rendering a template piece by
 piece, returning an iterator of strings. Flask provides the
 :func:`~flask.stream_template` and :func:`~flask.stream_template_string`
 functions to make this easier to use.
@@ -64,13 +49,13 @@ the template.
 Streaming with Context
 ----------------------
 
-The :data:`.request` proxy will not be active while the generator is
-running, because the app has already returned control to the WSGI server at that
-point. If you try to access ``request``, you'll get a ``RuntimeError``.
+The :data:`~flask.request` will not be active while the generator is
+running, because the view has already returned at that point. If you try
+to access ``request``, you'll get a ``RuntimeError``.
 
 If your generator function relies on data in ``request``, use the
-:func:`.stream_with_context` wrapper. This will keep the request context active
-during the generator.
+:func:`~flask.stream_with_context` wrapper. This will keep the request
+context active during the generator.
 
 .. code-block:: python
 

docs/patterns/wtforms.rst

@@ -99,7 +99,7 @@ WTForm's field function, which renders the field for us.  The keyword
 arguments will be inserted as HTML attributes.  So, for example, you can
 call ``render_field(form.username, class='username')`` to add a class to
 the input element.  Note that WTForms returns standard Python strings,
-so we have to tell Jinja that this data is already HTML-escaped with
+so we have to tell Jinja2 that this data is already HTML-escaped with
 the ``|safe`` filter.
 
 Here is the :file:`register.html` template for the function we used above, which

docs/quickstart.rst

@@ -139,16 +139,18 @@ how you're using untrusted data.
 
 .. code-block:: python
 
-    from flask import request
     from markupsafe import escape
 
-    @app.route("/hello")
-    def hello():
-        name = request.args.get("name", "Flask")
+    @app.route("/<name>")
+    def hello(name):
         return f"Hello, {escape(name)}!"
 
-If a user submits ``/hello?name=<script>alert("bad")</script>``, escaping causes
-it to be rendered as text, rather than running the script in the user's browser.
+If a user managed to submit the name ``<script>alert("bad")</script>``,
+escaping causes it to be rendered as text, rather than running the
+script in the user's browser.
+
+``<name>`` in the route captures a value from the URL and passes it to
+the view function. These variable rules are explained below.
 
 
 Routing
@@ -258,7 +260,7 @@ Why would you want to build URLs using the URL reversing function
 For example, here we use the :meth:`~flask.Flask.test_request_context` method
 to try out :func:`~flask.url_for`. :meth:`~flask.Flask.test_request_context`
 tells Flask to behave as though it's handling a request even while we use a
-Python shell. See :doc:`/appcontext`.
+Python shell. See :ref:`context-locals`.
 
 .. code-block:: python
 
@@ -352,7 +354,7 @@ Rendering Templates
 
 Generating HTML from within Python is not fun, and actually pretty
 cumbersome because you have to do the HTML escaping on your own to keep
-the application secure.  Because of that Flask configures the `Jinja
+the application secure.  Because of that Flask configures the `Jinja2
 <https://palletsprojects.com/p/jinja/>`_ template engine for you automatically.
 
 Templates can be used to generate any type of text file. For web applications, you'll
@@ -373,7 +375,7 @@ Here's a simple example of how to render a template::
     @app.route('/hello/')
     @app.route('/hello/<name>')
     def hello(name=None):
-        return render_template('hello.html', person=name)
+        return render_template('hello.html', name=name)
 
 Flask will look for templates in the :file:`templates` folder.  So if your
 application is a module, this folder is next to that module, if it's a
@@ -392,8 +394,8 @@ package it's actually inside your package:
         /templates
             /hello.html
 
-For templates you can use the full power of Jinja templates.  Head over
-to the official `Jinja Template Documentation
+For templates you can use the full power of Jinja2 templates.  Head over
+to the official `Jinja2 Template Documentation
 <https://jinja.palletsprojects.com/templates/>`_ for more information.
 
 Here is an example template:
@@ -402,8 +404,8 @@ Here is an example template:
 
     <!doctype html>
     <title>Hello from Flask</title>
-    {% if person %}
-      <h1>Hello {{ person }}!</h1>
+    {% if name %}
+      <h1>Hello {{ name }}!</h1>
     {% else %}
       <h1>Hello, World!</h1>
     {% endif %}
@@ -417,7 +419,7 @@ know how that works, see :doc:`patterns/templateinheritance`. Basically
 template inheritance makes it possible to keep certain elements on each
 page (like header, navigation and footer).
 
-Automatic escaping is enabled, so if ``person`` contains HTML it will be escaped
+Automatic escaping is enabled, so if ``name`` contains HTML it will be escaped
 automatically.  If you can trust a variable and you know that it will be
 safe HTML (for example because it came from a module that converts wiki
 markup to HTML) you can mark it as safe by using the
@@ -449,58 +451,105 @@ Here is a basic introduction to how the :class:`~markupsafe.Markup` class works:
 Accessing Request Data
 ----------------------
 
-For web applications it's crucial to react to the data a client sends to the
-server. In Flask this information is provided by the global :data:`.request`
-object, which is an instance of :class:`.Request`. This object has many
-attributes and methods to work with the incoming request data, but here is a
-broad overview. First it needs to be imported.
+For web applications it's crucial to react to the data a client sends to
+the server.  In Flask this information is provided by the global
+:class:`~flask.request` object.  If you have some experience with Python
+you might be wondering how that object can be global and how Flask
+manages to still be threadsafe.  The answer is context locals:
 
-.. code-block:: python
+
+.. _context-locals:
+
+Context Locals
+``````````````
+
+.. admonition:: Insider Information
+
+   If you want to understand how that works and how you can implement
+   tests with context locals, read this section, otherwise just skip it.
+
+Certain objects in Flask are global objects, but not of the usual kind.
+These objects are actually proxies to objects that are local to a specific
+context.  What a mouthful.  But that is actually quite easy to understand.
+
+Imagine the context being the handling thread.  A request comes in and the
+web server decides to spawn a new thread (or something else, the
+underlying object is capable of dealing with concurrency systems other
+than threads).  When Flask starts its internal request handling it
+figures out that the current thread is the active context and binds the
+current application and the WSGI environments to that context (thread).
+It does that in an intelligent way so that one application can invoke another
+application without breaking.
+
+So what does this mean to you?  Basically you can completely ignore that
+this is the case unless you are doing something like unit testing.  You
+will notice that code which depends on a request object will suddenly break
+because there is no request object.  The solution is creating a request
+object yourself and binding it to the context.  The easiest solution for
+unit testing is to use the :meth:`~flask.Flask.test_request_context`
+context manager.  In combination with the ``with`` statement it will bind a
+test request so that you can interact with it.  Here is an example::
 
     from flask import request
 
-If you have some experience with Python you might be wondering how that object
-can be global when Flask handles multiple requests at a time. The answer is
-that :data:`.request` is actually a proxy, pointing at whatever request is
-currently being handled by a given worker, which is managed internally by Flask
-and Python. See :doc:`/appcontext` for much more information.
+    with app.test_request_context('/hello', method='POST'):
+        # now you can do something with the request until the
+        # end of the with block, such as basic assertions:
+        assert request.path == '/hello'
+        assert request.method == 'POST'
 
-The current request method is available in the :attr:`~.Request.method`
-attribute. To access form data (data transmitted in a ``POST`` or ``PUT``
-request), use the :attr:`~flask.Request.form` attribute, which behaves like a
-dict.
+The other possibility is passing a whole WSGI environment to the
+:meth:`~flask.Flask.request_context` method::
 
-.. code-block:: python
+    with app.request_context(environ):
+        assert request.method == 'POST'
 
-    @app.route("/login", methods=["GET", "POST"])
+The Request Object
+``````````````````
+
+The request object is documented in the API section and we will not cover
+it here in detail (see :class:`~flask.Request`). Here is a broad overview of
+some of the most common operations.  First of all you have to import it from
+the ``flask`` module::
+
+    from flask import request
+
+The current request method is available by using the
+:attr:`~flask.Request.method` attribute.  To access form data (data
+transmitted in a ``POST`` or ``PUT`` request) you can use the
+:attr:`~flask.Request.form` attribute.  Here is a full example of the two
+attributes mentioned above::
+
+    @app.route('/login', methods=['POST', 'GET'])
     def login():
         error = None
-
-        if request.method == "POST":
-            if valid_login(request.form["username"], request.form["password"]):
-                return store_login(request.form["username"])
+        if request.method == 'POST':
+            if valid_login(request.form['username'],
+                           request.form['password']):
+                return log_the_user_in(request.form['username'])
             else:
-                error = "Invalid username or password"
+                error = 'Invalid username/password'
+        # the code below is executed if the request method
+        # was GET or the credentials were invalid
+        return render_template('login.html', error=error)
 
-        # Executed if the request method was GET or the credentials were invalid.
-        return render_template("login.html", error=error)
+What happens if the key does not exist in the ``form`` attribute?  In that
+case a special :exc:`KeyError` is raised.  You can catch it like a
+standard :exc:`KeyError` but if you don't do that, a HTTP 400 Bad Request
+error page is shown instead.  So for many situations you don't have to
+deal with that problem.
 
-If the key does not exist in ``form``, a special :exc:`KeyError` is raised. You
-can catch it like a normal ``KeyError``, otherwise it will return a HTTP 400
-Bad Request error page. You can also use the
-:meth:`~werkzeug.datastructures.MultiDict.get` method to get a default
-instead of an error.
-
-To access parameters submitted in the URL (``?key=value``), use the
-:attr:`~.Request.args` attribute. Key errors behave the same as ``form``,
-returning a 400 response if not caught.
-
-.. code-block:: python
+To access parameters submitted in the URL (``?key=value``) you can use the
+:attr:`~flask.Request.args` attribute::
 
     searchword = request.args.get('key', '')
 
-For a full list of methods and attributes of the request object, see the
-:class:`~.Request` documentation.
+We recommend accessing URL parameters with `get` or by catching the
+:exc:`KeyError` because users might change the URL and presenting them a 400
+bad request page in that case is not user friendly.
+
+For a full list of methods and attributes of the request object, head over
+to the :class:`~flask.Request` documentation.
 
 
 File Uploads

docs/reqcontext.rst

@@ -1,6 +1,243 @@
-:orphan:
+.. currentmodule:: flask
 
 The Request Context
 ===================
 
-Obsolete, see :doc:`/appcontext` instead.
+The request context keeps track of the request-level data during a
+request. Rather than passing the request object to each function that
+runs during a request, the :data:`request` and :data:`session` proxies
+are accessed instead.
+
+This is similar to :doc:`/appcontext`, which keeps track of the
+application-level data independent of a request. A corresponding
+application context is pushed when a request context is pushed.
+
+
+Purpose of the Context
+----------------------
+
+When the :class:`Flask` application handles a request, it creates a
+:class:`Request` object based on the environment it received from the
+WSGI server. Because a *worker* (thread, process, or coroutine depending
+on the server) handles only one request at a time, the request data can
+be considered global to that worker during that request. Flask uses the
+term *context local* for this.
+
+Flask automatically *pushes* a request context when handling a request.
+View functions, error handlers, and other functions that run during a
+request will have access to the :data:`request` proxy, which points to
+the request object for the current request.
+
+
+Lifetime of the Context
+-----------------------
+
+When a Flask application begins handling a request, it pushes a request
+context, which also pushes an :doc:`app context </appcontext>`. When the
+request ends it pops the request context then the application context.
+
+The context is unique to each thread (or other worker type).
+:data:`request` cannot be passed to another thread, the other thread has
+a different context space and will not know about the request the parent
+thread was pointing to.
+
+Context locals are implemented using Python's :mod:`contextvars` and
+Werkzeug's :class:`~werkzeug.local.LocalProxy`. Python manages the
+lifetime of context vars automatically, and local proxy wraps that
+low-level interface to make the data easier to work with.
+
+
+Manually Push a Context
+-----------------------
+
+If you try to access :data:`request`, or anything that uses it, outside
+a request context, you'll get this error message:
+
+.. code-block:: pytb
+
+    RuntimeError: Working outside of request context.
+
+    This typically means that you attempted to use functionality that
+    needed an active HTTP request. Consult the documentation on testing
+    for information about how to avoid this problem.
+
+This should typically only happen when testing code that expects an
+active request. One option is to use the
+:meth:`test client <Flask.test_client>` to simulate a full request. Or
+you can use :meth:`~Flask.test_request_context` in a ``with`` block, and
+everything that runs in the block will have access to :data:`request`,
+populated with your test data. ::
+
+    def generate_report(year):
+        format = request.args.get("format")
+        ...
+
+    with app.test_request_context(
+        "/make_report/2017", query_string={"format": "short"}
+    ):
+        generate_report()
+
+If you see that error somewhere else in your code not related to
+testing, it most likely indicates that you should move that code into a
+view function.
+
+For information on how to use the request context from the interactive
+Python shell, see :doc:`/shell`.
+
+
+How the Context Works
+---------------------
+
+The :meth:`Flask.wsgi_app` method is called to handle each request. It
+manages the contexts during the request. Internally, the request and
+application contexts work like stacks. When contexts are pushed, the
+proxies that depend on them are available and point at information from
+the top item.
+
+When the request starts, a :class:`~ctx.RequestContext` is created and
+pushed, which creates and pushes an :class:`~ctx.AppContext` first if
+a context for that application is not already the top context. While
+these contexts are pushed, the :data:`current_app`, :data:`g`,
+:data:`request`, and :data:`session` proxies are available to the
+original thread handling the request.
+
+Other contexts may be pushed to change the proxies during a request.
+While this is not a common pattern, it can be used in advanced
+applications to, for example, do internal redirects or chain different
+applications together.
+
+After the request is dispatched and a response is generated and sent,
+the request context is popped, which then pops the application context.
+Immediately before they are popped, the :meth:`~Flask.teardown_request`
+and :meth:`~Flask.teardown_appcontext` functions are executed. These
+execute even if an unhandled exception occurred during dispatch.
+
+
+.. _callbacks-and-errors:
+
+Callbacks and Errors
+--------------------
+
+Flask dispatches a request in multiple stages which can affect the
+request, response, and how errors are handled. The contexts are active
+during all of these stages.
+
+A :class:`Blueprint` can add handlers for these events that are specific
+to the blueprint. The handlers for a blueprint will run if the blueprint
+owns the route that matches the request.
+
+#.  Before each request, :meth:`~Flask.before_request` functions are
+    called. If one of these functions return a value, the other
+    functions are skipped. The return value is treated as the response
+    and the view function is not called.
+
+#.  If the :meth:`~Flask.before_request` functions did not return a
+    response, the view function for the matched route is called and
+    returns a response.
+
+#.  The return value of the view is converted into an actual response
+    object and passed to the :meth:`~Flask.after_request`
+    functions. Each function returns a modified or new response object.
+
+#.  After the response is returned, the contexts are popped, which calls
+    the :meth:`~Flask.teardown_request` and
+    :meth:`~Flask.teardown_appcontext` functions. These functions are
+    called even if an unhandled exception was raised at any point above.
+
+If an exception is raised before the teardown functions, Flask tries to
+match it with an :meth:`~Flask.errorhandler` function to handle the
+exception and return a response. If no error handler is found, or the
+handler itself raises an exception, Flask returns a generic
+``500 Internal Server Error`` response. The teardown functions are still
+called, and are passed the exception object.
+
+If debug mode is enabled, unhandled exceptions are not converted to a
+``500`` response and instead are propagated to the WSGI server. This
+allows the development server to present the interactive debugger with
+the traceback.
+
+
+Teardown Callbacks
+~~~~~~~~~~~~~~~~~~
+
+The teardown callbacks are independent of the request dispatch, and are
+instead called by the contexts when they are popped. The functions are
+called even if there is an unhandled exception during dispatch, and for
+manually pushed contexts. This means there is no guarantee that any
+other parts of the request dispatch have run first. Be sure to write
+these functions in a way that does not depend on other callbacks and
+will not fail.
+
+During testing, it can be useful to defer popping the contexts after the
+request ends, so that their data can be accessed in the test function.
+Use the :meth:`~Flask.test_client` as a ``with`` block to preserve the
+contexts until the ``with`` block exits.
+
+.. code-block:: python
+
+    from flask import Flask, request
+
+    app = Flask(__name__)
+
+    @app.route('/')
+    def hello():
+        print('during view')
+        return 'Hello, World!'
+
+    @app.teardown_request
+    def show_teardown(exception):
+        print('after with block')
+
+    with app.test_request_context():
+        print('during with block')
+
+    # teardown functions are called after the context with block exits
+
+    with app.test_client() as client:
+        client.get('/')
+        # the contexts are not popped even though the request ended
+        print(request.path)
+
+    # the contexts are popped and teardown functions are called after
+    # the client with block exits
+
+Signals
+~~~~~~~
+
+The following signals are sent:
+
+#.  :data:`request_started` is sent before the :meth:`~Flask.before_request` functions
+    are called.
+#.  :data:`request_finished` is sent after the :meth:`~Flask.after_request` functions
+    are called.
+#.  :data:`got_request_exception` is sent when an exception begins to be handled, but
+    before an :meth:`~Flask.errorhandler` is looked up or called.
+#.  :data:`request_tearing_down` is sent after the :meth:`~Flask.teardown_request`
+    functions are called.
+
+
+.. _notes-on-proxies:
+
+Notes On Proxies
+----------------
+
+Some of the objects provided by Flask are proxies to other objects. The
+proxies are accessed in the same way for each worker thread, but
+point to the unique object bound to each worker behind the scenes as
+described on this page.
+
+Most of the time you don't have to care about that, but there are some
+exceptions where it is good to know that this object is actually a proxy:
+
+-   The proxy objects cannot fake their type as the actual object types.
+    If you want to perform instance checks, you have to do that on the
+    object being proxied.
+-   The reference to the proxied object is needed in some situations,
+    such as sending :doc:`signals` or passing data to a background
+    thread.
+
+If you need to access the underlying object that is proxied, use the
+:meth:`~werkzeug.local.LocalProxy._get_current_object` method::
+
+    app = current_app._get_current_object()
+    my_signal.send(app)

docs/security.rst

@@ -1,43 +1,9 @@
 Security Considerations
 =======================
 
-Web applications face many types of potential security problems, and it can be
-hard to get everything right, or even to know what "right" is in general. Flask
-tries to solve a few of these things by default, but there are other parts you
-may have to take care of yourself. Many of these solutions are tradeoffs, and
-will depend on each application's specific needs and threat model. Many hosting
-platforms may take care of certain types of problems without the need for the
-Flask application to handle them.
-
-Resource Use
-------------
-
-A common category of attacks is "Denial of Service" (DoS or DDoS). This is a
-very broad category, and different variants target different layers in a
-deployed application. In general, something is done to increase how much
-processing time or memory is used to handle each request, to the point where
-there are not enough resources to handle legitimate requests.
-
-Flask provides a few configuration options to handle resource use. They can
-also be set on individual requests to customize only that request. The
-documentation for each goes into more detail.
-
--   :data:`MAX_CONTENT_LENGTH` or :attr:`.Request.max_content_length` controls
-    how much data will be read from a request. It is not set by default,
-    although it will still block truly unlimited streams unless the WSGI server
-    indicates support.
--   :data:`MAX_FORM_MEMORY_SIZE` or :attr:`.Request.max_form_memory_size`
-    controls how large any non-file ``multipart/form-data`` field can be. It is
-    set to 500kB by default.
--   :data:`MAX_FORM_PARTS` or :attr:`.Request.max_form_parts` controls how many
-    ``multipart/form-data`` fields can be parsed. It is set to 1000 by default.
-    Combined with the default `max_form_memory_size`, this means that a form
-    will occupy at most 500MB of memory.
-
-Regardless of these settings, you should also review what settings are available
-from your operating system, container deployment (Docker etc), WSGI server, HTTP
-server, and hosting platform. They typically have ways to set process resource
-limits, timeouts, and other checks regardless of how Flask is configured.
+Web applications usually face all kinds of security problems and it's very
+hard to get everything right.  Flask tries to solve a few of these things
+for you, but there are a couple more you have to take care of yourself.
 
 .. _security-xss:
 
@@ -51,12 +17,12 @@ tags.  For more information on that have a look at the Wikipedia article
 on `Cross-Site Scripting
 <https://en.wikipedia.org/wiki/Cross-site_scripting>`_.
 
-Flask configures Jinja to automatically escape all values unless
+Flask configures Jinja2 to automatically escape all values unless
 explicitly told otherwise.  This should rule out all XSS problems caused
 in templates, but there are still other places where you have to be
 careful:
 
--   generating HTML without the help of Jinja
+-   generating HTML without the help of Jinja2
 -   calling :class:`~markupsafe.Markup` on data submitted by users
 -   sending out HTML from uploaded files, never do that, use the
     ``Content-Disposition: attachment`` header to prevent that problem.
@@ -65,7 +31,7 @@ careful:
     trick a browser to execute HTML.
 
 Another thing that is very important are unquoted attributes.  While
-Jinja can protect you from XSS issues by escaping HTML, there is one
+Jinja2 can protect you from XSS issues by escaping HTML, there is one
 thing it cannot protect you from: XSS by attribute injection.  To counter
 this possible attack vector, be sure to always quote your attributes with
 either double or single quotes when using Jinja expressions in them:
@@ -158,7 +124,7 @@ recommend reviewing each of the headers below for use in your application.
 The `Flask-Talisman`_ extension can be used to manage HTTPS and the security
 headers for you.
 
-.. _Flask-Talisman: https://github.com/wntrblm/flask-talisman
+.. _Flask-Talisman: https://github.com/GoogleCloudPlatform/flask-talisman
 
 HTTP Strict Transport Security (HSTS)
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -269,25 +235,17 @@ values (or any values that need secure signatures).
 .. _samesite_support: https://caniuse.com/#feat=same-site-cookie-attribute
 
 
-Host Header Validation
-----------------------
+HTTP Public Key Pinning (HPKP)
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-The ``Host`` header is used by the client to indicate what host name the request
-was made to. This is used, for example, by ``url_for(..., _external=True)`` to
-generate full URLs, for use in email or other messages outside the browser
-window.
+This tells the browser to authenticate with the server using only the specific
+certificate key to prevent MITM attacks.
 
-By default the app doesn't know what host(s) it is allowed to be accessed
-through, and assumes any host is valid. Although browsers do not allow setting
-the ``Host`` header, requests made by attackers in other scenarios could set
-the ``Host`` header to a value they want.
+.. warning::
+   Be careful when enabling this, as it is very difficult to undo if you set up
+   or upgrade your key incorrectly.
 
-When deploying your application, set :data:`TRUSTED_HOSTS` to restrict what
-values the ``Host`` header may be.
-
-The ``Host`` header may be modified by proxies in between the client and your
-application. See :doc:`deploying/proxy_fix` to tell your app which proxy values
-to trust.
+- https://developer.mozilla.org/en-US/docs/Web/HTTP/Public_Key_Pinning
 
 
 Copy/Paste to Terminal

docs/server.rst

@@ -77,7 +77,7 @@ following example shows that process id 6847 is using port 5000.
 
 macOS Monterey and later automatically starts a service that uses port
 5000. You can choose to disable this service instead of using a different port by
-searching for "AirPlay Receiver" in System Settings and toggling it off.
+searching for "AirPlay Receiver" in System Preferences and toggling it off.
 
 
 Deferred Errors on Reload

docs/shell.rst

@@ -1,37 +1,56 @@
 Working with the Shell
 ======================
 
-One of the reasons everybody loves Python is the interactive shell. It allows
-you to play around with code in real time and immediately get results back.
-Flask provides the ``flask shell`` CLI command to start an interactive Python
-shell with some setup done to make working with the Flask app easier.
+.. versionadded:: 0.3
 
-.. code-block:: text
+One of the reasons everybody loves Python is the interactive shell.  It
+basically allows you to execute Python commands in real time and
+immediately get results back.  Flask itself does not come with an
+interactive shell, because it does not require any specific setup upfront,
+just import your application and start playing around.
 
-    $ flask shell
+There are however some handy helpers to make playing around in the shell a
+more pleasant experience.  The main issue with interactive console
+sessions is that you're not triggering a request like a browser does which
+means that :data:`~flask.g`, :data:`~flask.request` and others are not
+available.  But the code you want to test might depend on them, so what
+can you do?
+
+This is where some helper functions come in handy.  Keep in mind however
+that these functions are not only there for interactive shell usage, but
+also for unit testing and other situations that require a faked request
+context.
+
+Generally it's recommended that you read :doc:`reqcontext` first.
+
+Command Line Interface
+----------------------
+
+Starting with Flask 0.11 the recommended way to work with the shell is the
+``flask shell`` command which does a lot of this automatically for you.
+For instance the shell is automatically initialized with a loaded
+application context.
+
+For more information see :doc:`/cli`.
 
 Creating a Request Context
 --------------------------
 
-``flask shell`` pushes an app context automatically, so :data:`.current_app` and
-:data:`.g` are already available. However, there is no HTTP request being
-handled in the shell, so :data:`.request` and :data:`.session` are not yet
-available.
-
 The easiest way to create a proper request context from the shell is by
 using the :attr:`~flask.Flask.test_request_context` method which creates
 us a :class:`~flask.ctx.RequestContext`:
 
 >>> ctx = app.test_request_context()
 
-Normally you would use the ``with`` statement to make this context active, but
-in the shell it's easier to call :meth:`~.RequestContext.push` and
-:meth:`~.RequestContext.pop` manually:
+Normally you would use the ``with`` statement to make this request object
+active, but in the shell it's easier to use the
+:meth:`~flask.ctx.RequestContext.push` and
+:meth:`~flask.ctx.RequestContext.pop` methods by hand:
 
 >>> ctx.push()
 
-From that point onwards you can work with the request object until you call
-``pop``:
+From that point onwards you can work with the request object until you
+call `pop`:
 
 >>> ctx.pop()
 

docs/signals.rst

@@ -144,10 +144,11 @@ function, you can pass ``current_app._get_current_object()`` as sender.
 Signals and Flask's Request Context
 -----------------------------------
 
-Context-local proxies are available between :data:`~flask.request_started` and
-:data:`~flask.request_finished`, so you can rely on :class:`flask.g` and others
-as needed. Note the limitations described in :ref:`signals-sending` and the
-:data:`~flask.request_tearing_down` signal.
+Signals fully support :doc:`reqcontext` when receiving signals.
+Context-local variables are consistently available between
+:data:`~flask.request_started` and :data:`~flask.request_finished`, so you can
+rely on :class:`flask.g` and others as needed.  Note the limitations described
+in :ref:`signals-sending` and the :data:`~flask.request_tearing_down` signal.
 
 
 Decorator Based Signal Subscriptions

docs/templating.rst

@@ -1,21 +1,21 @@
 Templates
 =========
 
-Flask leverages Jinja as its template engine.  You are obviously free to use
-a different template engine, but you still have to install Jinja to run
+Flask leverages Jinja2 as its template engine.  You are obviously free to use
+a different template engine, but you still have to install Jinja2 to run
 Flask itself.  This requirement is necessary to enable rich extensions.
-An extension can depend on Jinja being present.
+An extension can depend on Jinja2 being present.
 
-This section only gives a very quick introduction into how Jinja
+This section only gives a very quick introduction into how Jinja2
 is integrated into Flask.  If you want information on the template
-engine's syntax itself, head over to the official `Jinja Template
+engine's syntax itself, head over to the official `Jinja2 Template
 Documentation <https://jinja.palletsprojects.com/templates/>`_ for
 more information.
 
 Jinja Setup
 -----------
 
-Unless customized, Jinja is configured by Flask as follows:
+Unless customized, Jinja2 is configured by Flask as follows:
 
 -   autoescaping is enabled for all templates ending in ``.html``,
     ``.htm``, ``.xml``, ``.xhtml``, as well as ``.svg`` when using
@@ -25,13 +25,13 @@ Unless customized, Jinja is configured by Flask as follows:
 -   a template has the ability to opt in/out autoescaping with the
     ``{% autoescape %}`` tag.
 -   Flask inserts a couple of global functions and helpers into the
-    Jinja context, additionally to the values that are present by
+    Jinja2 context, additionally to the values that are present by
     default.
 
 Standard Context
 ----------------
 
-The following global variables are available within Jinja templates
+The following global variables are available within Jinja2 templates
 by default:
 
 .. data:: config
@@ -137,58 +137,32 @@ using in this block.
 
 .. _registering-filters:
 
-Registering Filters, Tests, and Globals
----------------------------------------
+Registering Filters
+-------------------
 
-The Flask app and blueprints provide decorators and methods to register your own
-filters, tests, and global functions for use in Jinja templates. They all follow
-the same pattern, so the following examples only discuss filters.
+If you want to register your own filters in Jinja2 you have two ways to do
+that.  You can either put them by hand into the
+:attr:`~flask.Flask.jinja_env` of the application or use the
+:meth:`~flask.Flask.template_filter` decorator.
 
-Decorate a function with :meth:`~.Flask.template_filter` to register it as a
-template filter.
+The two following examples work the same and both reverse an object::
 
-.. code-block:: python
+    @app.template_filter('reverse')
+    def reverse_filter(s):
+        return s[::-1]
 
-    @app.template_filter
-    def reverse(s):
-        return reversed(s)
+    def reverse_filter(s):
+        return s[::-1]
+    app.jinja_env.filters['reverse'] = reverse_filter
 
-.. code-block:: jinja
+In case of the decorator the argument is optional if you want to use the
+function name as name of the filter.  Once registered, you can use the filter
+in your templates in the same way as Jinja2's builtin filters, for example if
+you have a Python list in context called `mylist`::
 
-    {% for item in data | reverse %}
+    {% for x in mylist | reverse %}
     {% endfor %}
 
-By default it will use the name of the function as the name of the filter, but
-that can be changed by passing a name to the decorator.
-
-.. code-block:: python
-
-    @app.template_filter("reverse")
-    def reverse_filter(s):
-        return reversed(s)
-
-A filter can be registered separately using :meth:`~.Flask.add_template_filter`.
-The name is optional and will use the function name if not given.
-
-.. code-block:: python
-
-    def reverse_filter(s):
-        return reversed(s)
-
-    app.add_template_filter(reverse_filter, "reverse")
-
-For template tests, use the :meth:`~.Flask.template_test` decorator or
-:meth:`~.Flask.add_template_test` method. For template global functions, use the
-:meth:`~.Flask.template_global` decorator or :meth:`~.Flask.add_template_global`
-method.
-
-The same methods also exist on :class:`.Blueprint`, prefixed with ``app_`` to
-indicate that the registered functions will be available to all templates, not
-only when rendering from within the blueprint.
-
-The Jinja environment is also available as :attr:`~.Flask.jinja_env`. It may be
-modified directly, as you would when using Jinja outside Flask.
-
 
 Context Processors
 ------------------
@@ -237,7 +211,7 @@ strings. This can be used for streaming HTML in chunks to speed up
 initial page load, or to save memory when rendering a very large
 template.
 
-The Jinja template engine supports rendering a template piece
+The Jinja2 template engine supports rendering a template piece
 by piece, returning an iterator of strings. Flask provides the
 :func:`~flask.stream_template` and :func:`~flask.stream_template_string`
 functions to make this easier to use.
@@ -251,11 +225,5 @@ functions to make this easier to use.
         return stream_template("timeline.html")
 
 These functions automatically apply the
-:func:`~flask.stream_with_context` wrapper if a request is active, so that
-:data:`.request`, :data:`.session`, and :data:`.g` remain available in the
-template.
-
-More headers cannot be sent after the body has begun. Therefore, you must
-make sure all headers are set before starting the response. In particular,
-if the template will access ``session``, be sure to do so in the view as
-well so that the ``Vary: cookie`` header will be set.
+:func:`~flask.stream_with_context` wrapper if a request is active, so
+that it remains available in the template.

docs/testing.rst

@@ -192,7 +192,7 @@ which records the request that produced that response.
 .. code-block:: python
 
     def test_logout_redirect(client):
-        response = client.get("/logout", follow_redirects=True)
+        response = client.get("/logout")
         # Check that there was one redirect response.
         assert len(response.history) == 1
         # Check that the second request was to the index page.
@@ -275,10 +275,11 @@ command from the command line.
 Tests that depend on an Active Context
 --------------------------------------
 
-You may have functions that are called from views or commands, that expect an
-active :doc:`app context </appcontext>` because they access :data:`.request`,
-:data:`.session`, :data:`.g`, or :data:`.current_app`. Rather than testing them by
-making a request or invoking the command, you can create and activate a context
+You may have functions that are called from views or commands, that
+expect an active :doc:`application context </appcontext>` or
+:doc:`request context  </reqcontext>` because they access ``request``,
+``session``, or ``current_app``. Rather than testing them by making a
+request or invoking the command, you can create and activate a context
 directly.
 
 Use ``with app.app_context()`` to push an application context. For

docs/tutorial/blog.rst

@@ -305,7 +305,7 @@ The pattern ``{{ request.form['title'] or post['title'] }}`` is used to
 choose what data appears in the form. When the form hasn't been
 submitted, the original ``post`` data appears, but if invalid form data
 was posted you want to display that so the user can fix the error, so
-``request.form`` is used instead. :data:`.request` is another variable
+``request.form`` is used instead. :data:`request` is another variable
 that's automatically available in templates.
 
 

docs/tutorial/database.rst

@@ -37,7 +37,6 @@ response is sent.
     :caption: ``flaskr/db.py``
 
     import sqlite3
-    from datetime import datetime
 
     import click
     from flask import current_app, g
@@ -60,17 +59,17 @@ response is sent.
         if db is not None:
             db.close()
 
-:data:`.g` is a special object that is unique for each request. It is
+:data:`g` is a special object that is unique for each request. It is
 used to store data that might be accessed by multiple functions during
 the request. The connection is stored and reused instead of creating a
 new connection if ``get_db`` is called a second time in the same
 request.
 
-:data:`.current_app` is another special object that points to the Flask
+:data:`current_app` is another special object that points to the Flask
 application handling the request. Since you used an application factory,
 there is no application object when writing the rest of your code.
 ``get_db`` will be called when the application has been created and is
-handling a request, so :data:`.current_app` can be used.
+handling a request, so :data:`current_app` can be used.
 
 :func:`sqlite3.connect` establishes a connection to the file pointed at
 by the ``DATABASE`` configuration key. This file doesn't have to exist
@@ -133,11 +132,6 @@ Add the Python functions that will run these SQL commands to the
         init_db()
         click.echo('Initialized the database.')
 
-
-    sqlite3.register_converter(
-        "timestamp", lambda v: datetime.fromisoformat(v.decode())
-    )
-
 :meth:`open_resource() <Flask.open_resource>` opens a file relative to
 the ``flaskr`` package, which is useful since you won't necessarily know
 where that location is when deploying the application later. ``get_db``
@@ -148,10 +142,6 @@ read from the file.
 that calls the ``init_db`` function and shows a success message to the
 user. You can read :doc:`/cli` to learn more about writing commands.
 
-The call to :func:`sqlite3.register_converter` tells Python how to
-interpret timestamp values in the database. We convert the value to a
-:class:`datetime.datetime`.
-
 
 Register with the Application
 -----------------------------

docs/tutorial/factory.rst

@@ -56,7 +56,10 @@ directory should be treated as a package.
             app.config.from_mapping(test_config)
 
         # ensure the instance folder exists
-        os.makedirs(app.instance_path, exist_ok=True)
+        try:
+            os.makedirs(app.instance_path)
+        except OSError:
+            pass
 
         # a simple page that says hello
         @app.route('/hello')

docs/tutorial/layout.rst

@@ -81,7 +81,8 @@ By the end, your project layout will look like this:
     │   ├── test_auth.py
     │   └── test_blog.py
     ├── .venv/
-    └── pyproject.toml
+    ├── pyproject.toml
+    └── MANIFEST.in
 
 If you're using version control, the following files that are generated
 while running your project should be ignored. There may be other files
@@ -102,4 +103,8 @@ write. For example, with git:
     .coverage
     htmlcov/
 
+    dist/
+    build/
+    *.egg-info/
+
 Continue to :doc:`factory`.

docs/tutorial/templates.rst

@@ -71,7 +71,7 @@ specific sections.
       {% block content %}{% endblock %}
     </section>
 
-:data:`.g` is automatically available in templates. Based on if
+:data:`g` is automatically available in templates. Based on if
 ``g.user`` is set (from ``load_logged_in_user``), either the username
 and a log out link are displayed, or links to register and log in
 are displayed. :func:`url_for` is also automatically available, and is

docs/tutorial/tests.rst

@@ -311,7 +311,7 @@ input and error messages without writing the same code three times.
 
 The tests for the ``login`` view are very similar to those for
 ``register``. Rather than testing the data in the database,
-:data:`.session` should have ``user_id`` set after logging in.
+:data:`session` should have ``user_id`` set after logging in.
 
 .. code-block:: python
     :caption: ``tests/test_auth.py``
@@ -336,10 +336,10 @@ The tests for the ``login`` view are very similar to those for
         assert message in response.data
 
 Using ``client`` in a ``with`` block allows accessing context variables
-such as :data:`.session` after the response is returned. Normally,
+such as :data:`session` after the response is returned. Normally,
 accessing ``session`` outside of a request would raise an error.
 
-Testing ``logout`` is the opposite of ``login``. :data:`.session` should
+Testing ``logout`` is the opposite of ``login``. :data:`session` should
 not contain ``user_id`` after logging out.
 
 .. code-block:: python

docs/tutorial/views.rst

@@ -208,13 +208,13 @@ There are a few differences from the ``register`` view:
     password in the same way as the stored hash and securely compares
     them. If they match, the password is valid.
 
-#.  :data:`.session` is a :class:`dict` that stores data across requests.
+#.  :data:`session` is a :class:`dict` that stores data across requests.
     When validation succeeds, the user's ``id`` is stored in a new
     session. The data is stored in a *cookie* that is sent to the
     browser, and the browser then sends it back with subsequent requests.
     Flask securely *signs* the data so that it can't be tampered with.
 
-Now that the user's ``id`` is stored in the :data:`.session`, it will be
+Now that the user's ``id`` is stored in the :data:`session`, it will be
 available on subsequent requests. At the beginning of each request, if
 a user is logged in their information should be loaded and made
 available to other views.
@@ -236,7 +236,7 @@ available to other views.
 :meth:`bp.before_app_request() <Blueprint.before_app_request>` registers
 a function that runs before the view function, no matter what URL is
 requested. ``load_logged_in_user`` checks if a user id is stored in the
-:data:`.session` and gets that user's data from the database, storing it
+:data:`session` and gets that user's data from the database, storing it
 on :data:`g.user <g>`, which lasts for the length of the request. If
 there is no user id, or if the id doesn't exist, ``g.user`` will be
 ``None``.
@@ -245,7 +245,7 @@ there is no user id, or if the id doesn't exist, ``g.user`` will be
 Logout
 ------
 
-To log out, you need to remove the user id from the :data:`.session`.
+To log out, you need to remove the user id from the :data:`session`.
 Then ``load_logged_in_user`` won't load a user on subsequent requests.
 
 .. code-block:: python

examples/celery/pyproject.toml

@@ -3,8 +3,8 @@ name = "flask-example-celery"
 version = "1.0.0"
 description = "Example Flask application with Celery background tasks."
 readme = "README.md"
-classifiers = ["Private :: Do Not Upload"]
-dependencies = ["flask", "celery[redis]"]
+requires-python = ">=3.8"
+dependencies = ["flask>=2.2.2", "celery[redis]>=5.2.7"]
 
 [build-system]
 requires = ["flit_core<4"]

examples/javascript/README.rst

@@ -15,7 +15,7 @@ page. Demonstrates using |fetch|_, |XMLHttpRequest|_,  and
 .. |jQuery.ajax| replace:: ``jQuery.ajax``
 .. _jQuery.ajax: https://api.jquery.com/jQuery.ajax/
 
-.. _Flask docs: https://flask.palletsprojects.com/patterns/javascript/
+.. _Flask docs: https://flask.palletsprojects.com/patterns/jquery/
 
 
 Install

examples/javascript/pyproject.toml

@@ -3,13 +3,12 @@ name = "js_example"
 version = "1.1.0"
 description = "Demonstrates making AJAX requests to Flask."
 readme = "README.rst"
-license = {file = "LICENSE.txt"}
+license = {file = "LICENSE.rst"}
 maintainers = [{name = "Pallets", email = "contact@palletsprojects.com"}]
-classifiers = ["Private :: Do Not Upload"]
 dependencies = ["flask"]
 
 [project.urls]
-Documentation = "https://flask.palletsprojects.com/patterns/javascript/"
+Documentation = "https://flask.palletsprojects.com/patterns/jquery/"
 
 [project.optional-dependencies]
 test = ["pytest"]

examples/javascript/tests/test_js_example.py

@@ -5,7 +5,7 @@ from flask import template_rendered
 @pytest.mark.parametrize(
     ("path", "template_name"),
     (
-        ("/", "fetch.html"),
+        ("/", "xhr.html"),
         ("/plain", "xhr.html"),
         ("/fetch", "fetch.html"),
         ("/jquery", "jquery.html"),

examples/tutorial/flaskr/__init__.py

@@ -21,7 +21,10 @@ def create_app(test_config=None):
         app.config.update(test_config)
 
     # ensure the instance folder exists
-    os.makedirs(app.instance_path, exist_ok=True)
+    try:
+        os.makedirs(app.instance_path)
+    except OSError:
+        pass
 
     @app.route("/hello")
     def hello():

examples/tutorial/flaskr/db.py

@@ -1,5 +1,4 @@
 import sqlite3
-from datetime import datetime
 
 import click
 from flask import current_app
@@ -45,9 +44,6 @@ def init_db_command():
     click.echo("Initialized the database.")
 
 
-sqlite3.register_converter("timestamp", lambda v: datetime.fromisoformat(v.decode()))
-
-
 def init_app(app):
     """Register database functions with the Flask app. This is called by
     the application factory.

examples/tutorial/pyproject.toml

@@ -3,9 +3,8 @@ name = "flaskr"
 version = "1.0.0"
 description = "The basic blog app built in the Flask tutorial."
 readme = "README.rst"
-license = {file = "LICENSE.txt"}
+license = {text = "BSD-3-Clause"}
 maintainers = [{name = "Pallets", email = "contact@palletsprojects.com"}]
-classifiers = ["Private :: Do Not Upload"]
 dependencies = [
     "flask",
 ]

pyproject.toml

@@ -1,88 +1,50 @@
 [project]
 name = "Flask"
-version = "3.2.0.dev"
+version = "3.0.1"
 description = "A simple framework for building complex web applications."
-readme = "README.md"
-license = "BSD-3-Clause"
-license-files = ["LICENSE.txt"]
+readme = "README.rst"
+license = {file = "LICENSE.rst"}
 maintainers = [{name = "Pallets", email = "contact@palletsprojects.com"}]
 classifiers = [
     "Development Status :: 5 - Production/Stable",
     "Environment :: Web Environment",
     "Framework :: Flask",
     "Intended Audience :: Developers",
+    "License :: OSI Approved :: BSD License",
     "Operating System :: OS Independent",
     "Programming Language :: Python",
     "Topic :: Internet :: WWW/HTTP :: Dynamic Content",
     "Topic :: Internet :: WWW/HTTP :: WSGI",
     "Topic :: Internet :: WWW/HTTP :: WSGI :: Application",
     "Topic :: Software Development :: Libraries :: Application Frameworks",
-    "Typing :: Typed",
 ]
-requires-python = ">=3.10"
+requires-python = ">=3.8"
 dependencies = [
-    "blinker>=1.9.0",
+    "Werkzeug>=3.0.0",
+    "Jinja2>=3.1.2",
+    "itsdangerous>=2.1.2",
     "click>=8.1.3",
-    "itsdangerous>=2.2.0",
-    "jinja2>=3.1.2",
-    "markupsafe>=2.1.1",
-    "werkzeug>=3.1.0",
-]
-
-[project.optional-dependencies]
-async = ["asgiref>=3.2"]
-dotenv = ["python-dotenv"]
-
-[dependency-groups]
-dev = [
-    "ruff",
-    "tox",
-    "tox-uv",
-]
-docs = [
-    "pallets-sphinx-themes",
-    "sphinx<9",
-    "sphinx-tabs",
-    "sphinxcontrib-log-cabinet",
-]
-docs-auto = [
-    "sphinx-autobuild",
-]
-gha-update = [
-    "gha-update ; python_full_version >= '3.12'",
-]
-pre-commit = [
-    "pre-commit",
-    "pre-commit-uv",
-]
-tests = [
-    "asgiref",
-    "pytest",
-    "python-dotenv",
-]
-typing = [
-    "asgiref",
-    "cryptography",
-    "mypy",
-    "pyright",
-    "pytest",
-    "python-dotenv",
-    "types-contextvars",
-    "types-dataclasses",
+    "blinker>=1.6.2",
+    "importlib-metadata>=3.6.0; python_version < '3.10'",
 ]
 
 [project.urls]
 Donate = "https://palletsprojects.com/donate"
 Documentation = "https://flask.palletsprojects.com/"
-Changes = "https://flask.palletsprojects.com/page/changes/"
-Source = "https://github.com/pallets/flask/"
+Changes = "https://flask.palletsprojects.com/changes/"
+"Source Code" = "https://github.com/pallets/flask/"
+"Issue Tracker" = "https://github.com/pallets/flask/issues/"
 Chat = "https://discord.gg/pallets"
 
+[project.optional-dependencies]
+async = ["asgiref>=3.2"]
+dotenv = ["python-dotenv"]
+
 [project.scripts]
 flask = "flask.cli:main"
 
 [build-system]
-requires = ["flit_core>=3.11,<4"]
+requires = ["flit_core<4"]
 build-backend = "flit_core.buildapi"
 
 [tool.flit.module]
@@ -92,17 +54,16 @@ name = "flask"
 include = [
     "docs/",
     "examples/",
+    "requirements/",
     "tests/",
     "CHANGES.rst",
-    "uv.lock"
+    "CONTRIBUTING.rst",
+    "tox.ini",
 ]
 exclude = [
     "docs/_build/",
 ]
 
-[tool.uv]
-default-groups = ["dev", "pre-commit", "tests", "typing"]
-
 [tool.pytest.ini_options]
 testpaths = ["tests"]
 filterwarnings = [
@@ -116,16 +77,9 @@ source = ["flask", "tests"]
 [tool.coverage.paths]
 source = ["src", "*/site-packages"]
 
-[tool.coverage.report]
-exclude_also = [
-    "if t.TYPE_CHECKING",
-    "raise NotImplementedError",
-    ": \\.{3}",
-]
-
 [tool.mypy]
-python_version = "3.10"
-files = ["src", "tests/type_check"]
+python_version = "3.8"
+files = ["src/flask", "tests/typing"]
 show_error_codes = true
 pretty = true
 strict = true
@@ -139,16 +93,11 @@ module = [
 ]
 ignore_missing_imports = true
 
-[tool.pyright]
-pythonVersion = "3.10"
-include = ["src", "tests/type_check"]
-typeCheckingMode = "basic"
-
 [tool.ruff]
 src = ["src"]
 fix = true
 show-fixes = true
-output-format = "full"
+show-source = true
 
 [tool.ruff.lint]
 select = [
@@ -159,119 +108,8 @@ select = [
     "UP",  # pyupgrade
     "W",  # pycodestyle warning
 ]
+ignore-init-module-imports = true
 
 [tool.ruff.lint.isort]
 force-single-line = true
 order-by-type = false
-
-[tool.codespell]
-ignore-words-list = "te"
-
-[tool.tox]
-env_list = [
-    "py3.14", "py3.14t",
-    "py3.13", "py3.12", "py3.11", "py3.10",
-    "pypy3.11",
-    "tests-min", "tests-dev",
-    "style",
-    "typing",
-    "docs",
-]
-
-[tool.tox.env_run_base]
-description = "pytest on latest dependency versions"
-runner = "uv-venv-lock-runner"
-package = "wheel"
-wheel_build_env = ".pkg"
-constrain_package_deps = true
-use_frozen_constraints = true
-dependency_groups = ["tests"]
-env_tmp_dir = "{toxworkdir}/tmp/{envname}"
-commands = [[
-    "pytest", "-v", "--tb=short", "--basetemp={env_tmp_dir}",
-    {replace = "posargs", default = [], extend = true},
-]]
-
-[tool.tox.env.tests-min]
-description = "pytest on minimum dependency versions"
-base_python = ["3.14"]
-commands = [
-    [
-        "uv", "pip", "install",
-        "blinker==1.9.0",
-        "click==8.1.3",
-        "itsdangerous==2.2.0",
-        "jinja2==3.1.2",
-        "markupsafe==2.1.1",
-        "werkzeug==3.1.0",
-    ],
-    [
-        "pytest", "-v", "--tb=short", "--basetemp={env_tmp_dir}",
-        {replace = "posargs", default = [], extend = true},
-    ],
-]
-
-[tool.tox.env.tests-dev]
-description = "pytest on development dependency versions (git main branch)"
-base_python = ["3.10"]
-commands = [
-    [
-        "uv", "pip", "install",
-        "https://github.com/pallets-eco/blinker/archive/refs/heads/main.tar.gz",
-        "https://github.com/pallets/click/archive/refs/heads/main.tar.gz",
-        "https://github.com/pallets/itsdangerous/archive/refs/heads/main.tar.gz",
-        "https://github.com/pallets/jinja/archive/refs/heads/main.tar.gz",
-        "https://github.com/pallets/markupsafe/archive/refs/heads/main.tar.gz",
-        "https://github.com/pallets/werkzeug/archive/refs/heads/main.tar.gz",
-    ],
-    [
-        "pytest", "-v", "--tb=short", "--basetemp={env_tmp_dir}",
-        {replace = "posargs", default = [], extend = true},
-    ],
-]
-
-[tool.tox.env.style]
-description = "run all pre-commit hooks on all files"
-dependency_groups = ["pre-commit"]
-skip_install = true
-commands = [["pre-commit", "run", "--all-files"]]
-
-[tool.tox.env.typing]
-description = "run static type checkers"
-dependency_groups = ["typing"]
-commands = [
-    ["mypy"],
-    ["pyright"],
-]
-
-[tool.tox.env.docs]
-description = "build docs"
-dependency_groups = ["docs"]
-commands = [["sphinx-build", "-E", "-W", "-b", "dirhtml", "docs", "docs/_build/dirhtml"]]
-
-[tool.tox.env.docs-auto]
-description = "continuously rebuild docs and start a local server"
-dependency_groups = ["docs", "docs-auto"]
-commands = [["sphinx-autobuild", "-W", "-b", "dirhtml", "--watch", "src", "docs", "docs/_build/dirhtml"]]
-
-[tool.tox.env.update-actions]
-description = "update GitHub Actions pins"
-labels = ["update"]
-dependency_groups = ["gha-update"]
-skip_install = true
-commands = [["gha-update"]]
-
-[tool.tox.env.update-pre_commit]
-description = "update pre-commit pins"
-labels = ["update"]
-dependency_groups = ["pre-commit"]
-skip_install = true
-commands = [["pre-commit", "autoupdate", "--freeze", "-j4"]]
-
-[tool.tox.env.update-requirements]
-description = "update uv lock"
-labels = ["update"]
-dependency_groups = []
-no_default_groups = true
-skip_install = true
-commands = [["uv", "lock", {replace = "posargs", default = ["-U"], extend = true}]]

requirements-skip/README.md

@@ -0,0 +1,2 @@
+Dependabot will only update files in the `requirements` directory. This directory is
+separate because the pins in here should not be updated automatically.

requirements-skip/tests-dev.txt

@@ -0,0 +1,6 @@
+https://github.com/pallets/werkzeug/archive/refs/heads/main.tar.gz
+https://github.com/pallets/jinja/archive/refs/heads/main.tar.gz
+https://github.com/pallets/markupsafe/archive/refs/heads/main.tar.gz
+https://github.com/pallets/itsdangerous/archive/refs/heads/main.tar.gz
+https://github.com/pallets/click/archive/refs/heads/main.tar.gz
+https://github.com/pallets-eco/blinker/archive/refs/heads/main.tar.gz

requirements-skip/tests-min.in

@@ -0,0 +1,6 @@
+werkzeug==3.0.0
+jinja2==3.1.2
+markupsafe==2.1.1
+itsdangerous==2.1.2
+click==8.1.3
+blinker==1.6.2

requirements-skip/tests-min.txt

@@ -0,0 +1,21 @@
+#
+# This file is autogenerated by pip-compile with Python 3.11
+# by the following command:
+#
+#    pip-compile tests-min.in
+#
+blinker==1.6.2
+    # via -r tests-min.in
+click==8.1.3
+    # via -r tests-min.in
+itsdangerous==2.1.2
+    # via -r tests-min.in
+jinja2==3.1.2
+    # via -r tests-min.in
+markupsafe==2.1.1
+    # via
+    #   -r tests-min.in
+    #   jinja2
+    #   werkzeug
+werkzeug==3.0.0
+    # via -r tests-min.in

requirements/build.in

@@ -0,0 +1 @@
+build

requirements/build.txt

@@ -0,0 +1,12 @@
+#
+# This file is autogenerated by pip-compile with Python 3.11
+# by the following command:
+#
+#    pip-compile build.in
+#
+build==1.0.3
+    # via -r build.in
+packaging==23.2
+    # via build
+pyproject-hooks==1.0.0
+    # via build

requirements/dev.in

@@ -0,0 +1,6 @@
+-r docs.in
+-r tests.in
+-r typing.in
+pip-tools
+pre-commit
+tox

requirements/dev.txt

@@ -0,0 +1,151 @@
+#
+# This file is autogenerated by pip-compile with Python 3.11
+# by the following command:
+#
+#    pip-compile dev.in
+#
+alabaster==0.7.16
+    # via sphinx
+asgiref==3.7.2
+    # via
+    #   -r tests.in
+    #   -r typing.in
+babel==2.14.0
+    # via sphinx
+build==1.0.3
+    # via pip-tools
+cachetools==5.3.2
+    # via tox
+certifi==2023.11.17
+    # via requests
+cffi==1.16.0
+    # via cryptography
+cfgv==3.4.0
+    # via pre-commit
+chardet==5.2.0
+    # via tox
+charset-normalizer==3.3.2
+    # via requests
+click==8.1.7
+    # via pip-tools
+colorama==0.4.6
+    # via tox
+cryptography==41.0.7
+    # via -r typing.in
+distlib==0.3.8
+    # via virtualenv
+docutils==0.18.1
+    # via
+    #   sphinx
+    #   sphinx-tabs
+filelock==3.13.1
+    # via
+    #   tox
+    #   virtualenv
+identify==2.5.33
+    # via pre-commit
+idna==3.6
+    # via requests
+imagesize==1.4.1
+    # via sphinx
+iniconfig==2.0.0
+    # via pytest
+jinja2==3.1.3
+    # via sphinx
+markupsafe==2.1.3
+    # via jinja2
+mypy==1.8.0
+    # via -r typing.in
+mypy-extensions==1.0.0
+    # via mypy
+nodeenv==1.8.0
+    # via pre-commit
+packaging==23.2
+    # via
+    #   build
+    #   pallets-sphinx-themes
+    #   pyproject-api
+    #   pytest
+    #   sphinx
+    #   tox
+pallets-sphinx-themes==2.1.1
+    # via -r docs.in
+pip-tools==7.3.0
+    # via -r dev.in
+platformdirs==4.1.0
+    # via
+    #   tox
+    #   virtualenv
+pluggy==1.3.0
+    # via
+    #   pytest
+    #   tox
+pre-commit==3.6.0
+    # via -r dev.in
+pycparser==2.21
+    # via cffi
+pygments==2.17.2
+    # via
+    #   sphinx
+    #   sphinx-tabs
+pyproject-api==1.6.1
+    # via tox
+pyproject-hooks==1.0.0
+    # via build
+pytest==7.4.4
+    # via -r tests.in
+python-dotenv==1.0.0
+    # via
+    #   -r tests.in
+    #   -r typing.in
+pyyaml==6.0.1
+    # via pre-commit
+requests==2.31.0
+    # via sphinx
+snowballstemmer==2.2.0
+    # via sphinx
+sphinx==7.2.6
+    # via
+    #   -r docs.in
+    #   pallets-sphinx-themes
+    #   sphinx-issues
+    #   sphinx-tabs
+    #   sphinxcontrib-log-cabinet
+sphinx-issues==3.0.1
+    # via -r docs.in
+sphinx-tabs==3.4.4
+    # via -r docs.in
+sphinxcontrib-applehelp==1.0.8
+    # via sphinx
+sphinxcontrib-devhelp==1.0.6
+    # via sphinx
+sphinxcontrib-htmlhelp==2.0.5
+    # via sphinx
+sphinxcontrib-jsmath==1.0.1
+    # via sphinx
+sphinxcontrib-log-cabinet==1.0.1
+    # via -r docs.in
+sphinxcontrib-qthelp==1.0.7
+    # via sphinx
+sphinxcontrib-serializinghtml==1.1.10
+    # via sphinx
+tox==4.12.0
+    # via -r dev.in
+types-contextvars==2.4.7.3
+    # via -r typing.in
+types-dataclasses==0.6.6
+    # via -r typing.in
+typing-extensions==4.9.0
+    # via mypy
+urllib3==2.1.0
+    # via requests
+virtualenv==20.25.0
+    # via
+    #   pre-commit
+    #   tox
+wheel==0.42.0
+    # via pip-tools
+
+# The following packages are considered to be unsafe in a requirements file:
+# pip
+# setuptools

requirements/docs.in

@@ -0,0 +1,5 @@
+pallets-sphinx-themes
+sphinx
+sphinx-issues
+sphinxcontrib-log-cabinet
+sphinx-tabs

requirements/docs.txt

@@ -0,0 +1,67 @@
+#
+# This file is autogenerated by pip-compile with Python 3.11
+# by the following command:
+#
+#    pip-compile docs.in
+#
+alabaster==0.7.16
+    # via sphinx
+babel==2.14.0
+    # via sphinx
+certifi==2023.11.17
+    # via requests
+charset-normalizer==3.3.2
+    # via requests
+docutils==0.18.1
+    # via
+    #   sphinx
+    #   sphinx-tabs
+idna==3.6
+    # via requests
+imagesize==1.4.1
+    # via sphinx
+jinja2==3.1.3
+    # via sphinx
+markupsafe==2.1.3
+    # via jinja2
+packaging==23.2
+    # via
+    #   pallets-sphinx-themes
+    #   sphinx
+pallets-sphinx-themes==2.1.1
+    # via -r docs.in
+pygments==2.17.2
+    # via
+    #   sphinx
+    #   sphinx-tabs
+requests==2.31.0
+    # via sphinx
+snowballstemmer==2.2.0
+    # via sphinx
+sphinx==7.2.6
+    # via
+    #   -r docs.in
+    #   pallets-sphinx-themes
+    #   sphinx-issues
+    #   sphinx-tabs
+    #   sphinxcontrib-log-cabinet
+sphinx-issues==3.0.1
+    # via -r docs.in
+sphinx-tabs==3.4.4
+    # via -r docs.in
+sphinxcontrib-applehelp==1.0.8
+    # via sphinx
+sphinxcontrib-devhelp==1.0.6
+    # via sphinx
+sphinxcontrib-htmlhelp==2.0.5
+    # via sphinx
+sphinxcontrib-jsmath==1.0.1
+    # via sphinx
+sphinxcontrib-log-cabinet==1.0.1
+    # via -r docs.in
+sphinxcontrib-qthelp==1.0.7
+    # via sphinx
+sphinxcontrib-serializinghtml==1.1.10
+    # via sphinx
+urllib3==2.1.0
+    # via requests

requirements/tests.in

@@ -0,0 +1,4 @@
+pytest
+asgiref
+greenlet ; python_version < "3.11"
+python-dotenv

requirements/tests.txt

@@ -0,0 +1,18 @@
+#
+# This file is autogenerated by pip-compile with Python 3.11
+# by the following command:
+#
+#    pip-compile tests.in
+#
+asgiref==3.7.2
+    # via -r tests.in
+iniconfig==2.0.0
+    # via pytest
+packaging==23.2
+    # via pytest
+pluggy==1.3.0
+    # via pytest
+pytest==7.4.4
+    # via -r tests.in
+python-dotenv==1.0.0
+    # via -r tests.in

requirements/typing.in

@@ -0,0 +1,6 @@
+mypy
+types-contextvars
+types-dataclasses
+asgiref
+cryptography
+python-dotenv

requirements/typing.txt

@@ -0,0 +1,26 @@
+#
+# This file is autogenerated by pip-compile with Python 3.11
+# by the following command:
+#
+#    pip-compile typing.in
+#
+asgiref==3.7.2
+    # via -r typing.in
+cffi==1.16.0
+    # via cryptography
+cryptography==41.0.7
+    # via -r typing.in
+mypy==1.8.0
+    # via -r typing.in
+mypy-extensions==1.0.0
+    # via mypy
+pycparser==2.21
+    # via cffi
+python-dotenv==1.0.0
+    # via -r typing.in
+types-contextvars==2.4.7.3
+    # via -r typing.in
+types-dataclasses==0.6.6
+    # via -r typing.in
+typing-extensions==4.9.0
+    # via mypy

src/flask/__init__.py

@@ -1,3 +1,7 @@
+from __future__ import annotations
+
+import typing as t
+
 from . import json as json
 from .app import Flask as Flask
 from .blueprints import Blueprint as Blueprint
@@ -37,3 +41,20 @@ from .templating import stream_template as stream_template
 from .templating import stream_template_string as stream_template_string
 from .wrappers import Request as Request
 from .wrappers import Response as Response
+
+
+def __getattr__(name: str) -> t.Any:
+    if name == "__version__":
+        import importlib.metadata
+        import warnings
+
+        warnings.warn(
+            "The '__version__' attribute is deprecated and will be removed in"
+            " Flask 3.1. Use feature detection or"
+            " 'importlib.metadata.version(\"flask\")' instead.",
+            DeprecationWarning,
+            stacklevel=2,
+        )
+        return importlib.metadata.version("flask")
+
+    raise AttributeError(name)

src/flask/app.py

@@ -1,13 +1,11 @@
 from __future__ import annotations
 
 import collections.abc as cabc
-import inspect
 import os
 import sys
 import typing as t
 import weakref
 from datetime import timedelta
-from functools import update_wrapper
 from inspect import iscoroutinefunction
 from itertools import chain
 from types import TracebackType
@@ -26,22 +24,24 @@ from werkzeug.routing import RoutingException
 from werkzeug.routing import Rule
 from werkzeug.serving import is_running_from_reloader
 from werkzeug.wrappers import Response as BaseResponse
-from werkzeug.wsgi import get_host
 
 from . import cli
 from . import typing as ft
 from .ctx import AppContext
+from .ctx import RequestContext
 from .globals import _cv_app
-from .globals import app_ctx
+from .globals import _cv_request
+from .globals import current_app
 from .globals import g
 from .globals import request
+from .globals import request_ctx
 from .globals import session
-from .helpers import _CollectErrors
 from .helpers import get_debug_flag
 from .helpers import get_flashed_messages
 from .helpers import get_load_dotenv
 from .helpers import send_from_directory
 from .sansio.app import App
+from .sansio.scaffold import _sentinel
 from .sessions import SecureCookieSessionInterface
 from .sessions import SessionInterface
 from .signals import appcontext_tearing_down
@@ -59,7 +59,6 @@ if t.TYPE_CHECKING:  # pragma: no cover
 
     from .testing import FlaskClient
     from .testing import FlaskCliRunner
-    from .typing import HeadersValue
 
 T_shell_context_processor = t.TypeVar(
     "T_shell_context_processor", bound=ft.ShellContextProcessorCallable
@@ -77,35 +76,6 @@ def _make_timedelta(value: timedelta | int | None) -> timedelta | None:
     return timedelta(seconds=value)
 
 
-F = t.TypeVar("F", bound=t.Callable[..., t.Any])
-
-
-# Other methods may call the overridden method with the new ctx arg. Remove it
-# and call the method with the remaining args.
-def remove_ctx(f: F) -> F:
-    def wrapper(self: Flask, *args: t.Any, **kwargs: t.Any) -> t.Any:
-        if args and isinstance(args[0], AppContext):
-            args = args[1:]
-
-        return f(self, *args, **kwargs)
-
-    return update_wrapper(wrapper, f)  # type: ignore[return-value]
-
-
-# The overridden method may call super().base_method without the new ctx arg.
-# Add it to the args for the call.
-def add_ctx(f: F) -> F:
-    def wrapper(self: Flask, *args: t.Any, **kwargs: t.Any) -> t.Any:
-        if not args:
-            args = (app_ctx._get_current_object(),)
-        elif not isinstance(args[0], AppContext):
-            args = (app_ctx._get_current_object(), *args)
-
-        return f(self, *args, **kwargs)
-
-    return update_wrapper(wrapper, f)  # type: ignore[return-value]
-
-
 class Flask(App):
     """The flask object implements a WSGI application and acts as the central
     object.  It is passed the name of the module or package of the
@@ -209,10 +179,8 @@ class Flask(App):
             "TESTING": False,
             "PROPAGATE_EXCEPTIONS": None,
             "SECRET_KEY": None,
-            "SECRET_KEY_FALLBACKS": None,
             "PERMANENT_SESSION_LIFETIME": timedelta(days=31),
             "USE_X_SENDFILE": False,
-            "TRUSTED_HOSTS": None,
             "SERVER_NAME": None,
             "APPLICATION_ROOT": "/",
             "SESSION_COOKIE_NAME": "session",
@@ -220,12 +188,9 @@ class Flask(App):
             "SESSION_COOKIE_PATH": None,
             "SESSION_COOKIE_HTTPONLY": True,
             "SESSION_COOKIE_SECURE": False,
-            "SESSION_COOKIE_PARTITIONED": False,
             "SESSION_COOKIE_SAMESITE": None,
             "SESSION_REFRESH_EACH_REQUEST": True,
             "MAX_CONTENT_LENGTH": None,
-            "MAX_FORM_MEMORY_SIZE": 500_000,
-            "MAX_FORM_PARTS": 1_000,
             "SEND_FILE_MAX_AGE_DEFAULT": None,
             "TRAP_BAD_REQUEST_ERRORS": None,
             "TRAP_HTTP_EXCEPTIONS": False,
@@ -233,7 +198,6 @@ class Flask(App):
             "PREFERRED_URL_SCHEME": "http",
             "TEMPLATES_AUTO_RELOAD": None,
             "MAX_COOKIE_SIZE": 4093,
-            "PROVIDE_AUTOMATIC_OPTIONS": True,
         }
     )
 
@@ -251,62 +215,6 @@ class Flask(App):
     #: .. versionadded:: 0.8
     session_interface: SessionInterface = SecureCookieSessionInterface()
 
-    def __init_subclass__(cls, **kwargs: t.Any) -> None:
-        import warnings
-
-        # These method signatures were updated to take a ctx param. Detect
-        # overridden methods in subclasses that still have the old signature.
-        # Show a deprecation warning and wrap to call with correct args.
-        for method in (
-            cls.handle_http_exception,
-            cls.handle_user_exception,
-            cls.handle_exception,
-            cls.log_exception,
-            cls.dispatch_request,
-            cls.full_dispatch_request,
-            cls.finalize_request,
-            cls.make_default_options_response,
-            cls.preprocess_request,
-            cls.process_response,
-            cls.do_teardown_request,
-            cls.do_teardown_appcontext,
-        ):
-            base_method = getattr(Flask, method.__name__)
-
-            if method is base_method:
-                # not overridden
-                continue
-
-            # get the second parameter (first is self)
-            iter_params = iter(inspect.signature(method).parameters.values())
-            next(iter_params)
-            param = next(iter_params, None)
-
-            # must have second parameter named ctx or annotated AppContext
-            if param is None or not (
-                # no annotation, match name
-                (param.annotation is inspect.Parameter.empty and param.name == "ctx")
-                or (
-                    # string annotation, access path ends with AppContext
-                    isinstance(param.annotation, str)
-                    and param.annotation.rpartition(".")[2] == "AppContext"
-                )
-                or (
-                    # class annotation
-                    inspect.isclass(param.annotation)
-                    and issubclass(param.annotation, AppContext)
-                )
-            ):
-                warnings.warn(
-                    f"The '{method.__name__}' method now takes 'ctx: AppContext'"
-                    " as the first parameter. The old signature is deprecated"
-                    " and will not be supported in Flask 4.0.",
-                    DeprecationWarning,
-                    stacklevel=2,
-                )
-                setattr(cls, method.__name__, remove_ctx(method))
-                setattr(Flask, method.__name__, add_ctx(base_method))
-
     def __init__(
         self,
         import_name: str,
@@ -333,25 +241,15 @@ class Flask(App):
             root_path=root_path,
         )
 
-        #: The Click command group for registering CLI commands for this
-        #: object. The commands are available from the ``flask`` command
-        #: once the application has been discovered and blueprints have
-        #: been registered.
-        self.cli = cli.AppGroup()
-
-        # Set the name of the Click group in case someone wants to add
-        # the app's commands to another CLI tool.
-        self.cli.name = self.name
-
         # Add a static route using the provided static_url_path, static_host,
         # and static_folder if there is a configured static_folder.
         # Note we do this without checking if static_folder exists.
         # For one, it might be created while the server is running (e.g. during
         # development). Also, Google App Engine stores static files somewhere
         if self.has_static_folder:
-            assert bool(static_host) == host_matching, (
-                "Invalid static_host/host_matching combination"
-            )
+            assert (
+                bool(static_host) == host_matching
+            ), "Invalid static_host/host_matching combination"
             # Use a weakref to avoid creating a reference cycle between the app
             # and the view function (see #3761).
             self_ref = weakref.ref(self)
@@ -359,7 +257,7 @@ class Flask(App):
                 f"{self.static_url_path}/<path:filename>",
                 endpoint="static",
                 host=static_host,
-                view_func=lambda **kw: self_ref().send_static_file(**kw),  # type: ignore
+                view_func=lambda **kw: self_ref().send_static_file(**kw),  # type: ignore # noqa: B950
             )
 
     def get_send_file_max_age(self, filename: str | None) -> int | None:
@@ -379,7 +277,7 @@ class Flask(App):
 
         .. versionadded:: 0.9
         """
-        value = self.config["SEND_FILE_MAX_AGE_DEFAULT"]
+        value = current_app.config["SEND_FILE_MAX_AGE_DEFAULT"]
 
         if value is None:
             return None
@@ -411,10 +309,9 @@ class Flask(App):
             t.cast(str, self.static_folder), filename, max_age=max_age
         )
 
-    def open_resource(
-        self, resource: str, mode: str = "rb", encoding: str | None = None
-    ) -> t.IO[t.AnyStr]:
-        """Open a resource file relative to :attr:`root_path` for reading.
+    def open_resource(self, resource: str, mode: str = "rb") -> t.IO[t.AnyStr]:
+        """Open a resource file relative to :attr:`root_path` for
+        reading.
 
         For example, if the file ``schema.sql`` is next to the file
         ``app.py`` where the ``Flask`` app is defined, it can be opened
@@ -425,46 +322,31 @@ class Flask(App):
             with app.open_resource("schema.sql") as f:
                 conn.executescript(f.read())
 
-        :param resource: Path to the resource relative to :attr:`root_path`.
-        :param mode: Open the file in this mode. Only reading is supported,
-            valid values are ``"r"`` (or ``"rt"``) and ``"rb"``.
-        :param encoding: Open the file with this encoding when opening in text
-            mode. This is ignored when opening in binary mode.
+        :param resource: Path to the resource relative to
+            :attr:`root_path`.
+        :param mode: Open the file in this mode. Only reading is
+            supported, valid values are "r" (or "rt") and "rb".
+
+        Note this is a duplicate of the same method in the Flask
+        class.
 
-        .. versionchanged:: 3.1
-            Added the ``encoding`` parameter.
         """
         if mode not in {"r", "rt", "rb"}:
             raise ValueError("Resources can only be opened for reading.")
 
-        path = os.path.join(self.root_path, resource)
+        return open(os.path.join(self.root_path, resource), mode)
 
-        if mode == "rb":
-            return open(path, mode)  # pyright: ignore
+    def open_instance_resource(self, resource: str, mode: str = "rb") -> t.IO[t.AnyStr]:
+        """Opens a resource from the application's instance folder
+        (:attr:`instance_path`).  Otherwise works like
+        :meth:`open_resource`.  Instance resources can also be opened for
+        writing.
 
-        return open(path, mode, encoding=encoding)
-
-    def open_instance_resource(
-        self, resource: str, mode: str = "rb", encoding: str | None = "utf-8"
-    ) -> t.IO[t.AnyStr]:
-        """Open a resource file relative to the application's instance folder
-        :attr:`instance_path`. Unlike :meth:`open_resource`, files in the
-        instance folder can be opened for writing.
-
-        :param resource: Path to the resource relative to :attr:`instance_path`.
-        :param mode: Open the file in this mode.
-        :param encoding: Open the file with this encoding when opening in text
-            mode. This is ignored when opening in binary mode.
-
-        .. versionchanged:: 3.1
-            Added the ``encoding`` parameter.
+        :param resource: the name of the resource.  To access resources within
+                         subfolders use forward slashes as separator.
+        :param mode: resource file opening mode, default is 'rb'.
         """
-        path = os.path.join(self.instance_path, resource)
-
-        if "b" in mode:
-            return open(path, mode)
-
-        return open(path, mode, encoding=encoding)
+        return open(os.path.join(self.instance_path, resource), mode)
 
     def create_jinja_environment(self) -> Environment:
         """Create the Jinja environment based on :attr:`jinja_options`
@@ -511,45 +393,32 @@ class Flask(App):
         is created at a point where the request context is not yet set
         up so the request is passed explicitly.
 
-        .. versionchanged:: 3.1
-            If :data:`SERVER_NAME` is set, it does not restrict requests to
-            only that domain, for both ``subdomain_matching`` and
-            ``host_matching``.
+        .. versionadded:: 0.6
+
+        .. versionchanged:: 0.9
+           This can now also be called without a request object when the
+           URL adapter is created for the application context.
 
         .. versionchanged:: 1.0
             :data:`SERVER_NAME` no longer implicitly enables subdomain
             matching. Use :attr:`subdomain_matching` instead.
-
-        .. versionchanged:: 0.9
-           This can be called outside a request when the URL adapter is created
-           for an application context.
-
-        .. versionadded:: 0.6
         """
         if request is not None:
-            if (trusted_hosts := self.config["TRUSTED_HOSTS"]) is not None:
-                request.trusted_hosts = trusted_hosts
-
-            # Check trusted_hosts here until bind_to_environ does.
-            request.host = get_host(request.environ, request.trusted_hosts)  # pyright: ignore
-            subdomain = None
-            server_name = self.config["SERVER_NAME"]
-
-            if self.url_map.host_matching:
-                # Don't pass SERVER_NAME, otherwise it's used and the actual
-                # host is ignored, which breaks host matching.
-                server_name = None
-            elif not self.subdomain_matching:
-                # Werkzeug doesn't implement subdomain matching yet. Until then,
-                # disable it by forcing the current subdomain to the default, or
-                # the empty string.
-                subdomain = self.url_map.default_subdomain or ""
+            # If subdomain matching is disabled (the default), use the
+            # default subdomain in all cases. This should be the default
+            # in Werkzeug but it currently does not have that feature.
+            if not self.subdomain_matching:
+                subdomain = self.url_map.default_subdomain or None
+            else:
+                subdomain = None
 
             return self.url_map.bind_to_environ(
-                request.environ, server_name=server_name, subdomain=subdomain
+                request.environ,
+                server_name=self.config["SERVER_NAME"],
+                subdomain=subdomain,
             )
-
-        # Need at least SERVER_NAME to match/build outside a request.
+        # We need at the very least the server name to be set for this
+        # to work.
         if self.config["SERVER_NAME"] is not None:
             return self.url_map.bind(
                 self.config["SERVER_NAME"],
@@ -587,9 +456,7 @@ class Flask(App):
 
         raise FormDataRoutingRedirect(request)
 
-    def update_template_context(
-        self, ctx: AppContext, context: dict[str, t.Any]
-    ) -> None:
+    def update_template_context(self, context: dict[str, t.Any]) -> None:
         """Update the template context with some commonly used variables.
         This injects request, session, config and g into the template
         context as well as everything template context processors want
@@ -603,8 +470,8 @@ class Flask(App):
         names: t.Iterable[str | None] = (None,)
 
         # A template may be rendered outside a request context.
-        if ctx.has_request:
-            names = chain(names, reversed(ctx.request.blueprints))
+        if request:
+            names = chain(names, reversed(request.blueprints))
 
         # The values passed to render_template take precedence. Keep a
         # copy to re-apply after all context functions.
@@ -828,7 +695,7 @@ class Flask(App):
         return cls(self, **kwargs)  # type: ignore
 
     def handle_http_exception(
-        self, ctx: AppContext, e: HTTPException
+        self, e: HTTPException
     ) -> HTTPException | ft.ResponseReturnValue:
         """Handles an HTTP exception.  By default this will invoke the
         registered error handlers and fall back to returning the
@@ -857,13 +724,13 @@ class Flask(App):
         if isinstance(e, RoutingException):
             return e
 
-        handler = self._find_error_handler(e, ctx.request.blueprints)
+        handler = self._find_error_handler(e, request.blueprints)
         if handler is None:
             return e
         return self.ensure_sync(handler)(e)  # type: ignore[no-any-return]
 
     def handle_user_exception(
-        self, ctx: AppContext, e: Exception
+        self, e: Exception
     ) -> HTTPException | ft.ResponseReturnValue:
         """This method is called whenever an exception occurs that
         should be handled. A special case is :class:`~werkzeug
@@ -885,16 +752,16 @@ class Flask(App):
             e.show_exception = True
 
         if isinstance(e, HTTPException) and not self.trap_http_exception(e):
-            return self.handle_http_exception(ctx, e)
+            return self.handle_http_exception(e)
 
-        handler = self._find_error_handler(e, ctx.request.blueprints)
+        handler = self._find_error_handler(e, request.blueprints)
 
         if handler is None:
             raise
 
         return self.ensure_sync(handler)(e)  # type: ignore[no-any-return]
 
-    def handle_exception(self, ctx: AppContext, e: Exception) -> Response:
+    def handle_exception(self, e: Exception) -> Response:
         """Handle an exception that did not have an error handler
         associated with it, or that was raised from an error handler.
         This always causes a 500 ``InternalServerError``.
@@ -937,20 +804,19 @@ class Flask(App):
 
             raise e
 
-        self.log_exception(ctx, exc_info)
+        self.log_exception(exc_info)
         server_error: InternalServerError | ft.ResponseReturnValue
         server_error = InternalServerError(original_exception=e)
-        handler = self._find_error_handler(server_error, ctx.request.blueprints)
+        handler = self._find_error_handler(server_error, request.blueprints)
 
         if handler is not None:
             server_error = self.ensure_sync(handler)(server_error)
 
-        return self.finalize_request(ctx, server_error, from_error_handler=True)
+        return self.finalize_request(server_error, from_error_handler=True)
 
     def log_exception(
         self,
-        ctx: AppContext,
-        exc_info: tuple[type, BaseException, TracebackType] | tuple[None, None, None],
+        exc_info: (tuple[type, BaseException, TracebackType] | tuple[None, None, None]),
     ) -> None:
         """Logs an exception.  This is called by :meth:`handle_exception`
         if debugging is disabled and right before the handler is called.
@@ -960,10 +826,10 @@ class Flask(App):
         .. versionadded:: 0.8
         """
         self.logger.error(
-            f"Exception on {ctx.request.path} [{ctx.request.method}]", exc_info=exc_info
+            f"Exception on {request.path} [{request.method}]", exc_info=exc_info
         )
 
-    def dispatch_request(self, ctx: AppContext) -> ft.ResponseReturnValue:
+    def dispatch_request(self) -> ft.ResponseReturnValue:
         """Does the request dispatching.  Matches the URL and returns the
         return value of the view or error handler.  This does not have to
         be a response object.  In order to convert the return value to a
@@ -973,8 +839,7 @@ class Flask(App):
            This no longer does the exception handling, this code was
            moved to the new :meth:`full_dispatch_request`.
         """
-        req = ctx.request
-
+        req = request_ctx.request
         if req.routing_exception is not None:
             self.raise_routing_exception(req)
         rule: Rule = req.url_rule  # type: ignore[assignment]
@@ -984,43 +849,31 @@ class Flask(App):
             getattr(rule, "provide_automatic_options", False)
             and req.method == "OPTIONS"
         ):
-            return self.make_default_options_response(ctx)
+            return self.make_default_options_response()
         # otherwise dispatch to the handler for that endpoint
         view_args: dict[str, t.Any] = req.view_args  # type: ignore[assignment]
         return self.ensure_sync(self.view_functions[rule.endpoint])(**view_args)  # type: ignore[no-any-return]
 
-    def full_dispatch_request(self, ctx: AppContext) -> Response:
+    def full_dispatch_request(self) -> Response:
         """Dispatches the request and on top of that performs request
         pre and postprocessing as well as HTTP exception catching and
         error handling.
 
         .. versionadded:: 0.7
         """
-        if not self._got_first_request and self.should_ignore_error is not None:
-            import warnings
-
-            warnings.warn(
-                "The 'should_ignore_error' method is deprecated and will"
-                " be removed in Flask 3.3. Handle errors as needed in"
-                " teardown handlers instead.",
-                DeprecationWarning,
-                stacklevel=1,
-            )
-
         self._got_first_request = True
 
         try:
             request_started.send(self, _async_wrapper=self.ensure_sync)
-            rv = self.preprocess_request(ctx)
+            rv = self.preprocess_request()
             if rv is None:
-                rv = self.dispatch_request(ctx)
+                rv = self.dispatch_request()
         except Exception as e:
-            rv = self.handle_user_exception(ctx, e)
-        return self.finalize_request(ctx, rv)
+            rv = self.handle_user_exception(e)
+        return self.finalize_request(rv)
 
     def finalize_request(
         self,
-        ctx: AppContext,
         rv: ft.ResponseReturnValue | HTTPException,
         from_error_handler: bool = False,
     ) -> Response:
@@ -1038,7 +891,7 @@ class Flask(App):
         """
         response = self.make_response(rv)
         try:
-            response = self.process_response(ctx, response)
+            response = self.process_response(response)
             request_finished.send(
                 self, _async_wrapper=self.ensure_sync, response=response
             )
@@ -1050,14 +903,15 @@ class Flask(App):
             )
         return response
 
-    def make_default_options_response(self, ctx: AppContext) -> Response:
+    def make_default_options_response(self) -> Response:
         """This method is called to create the default ``OPTIONS`` response.
         This can be changed through subclassing to change the default
         behavior of ``OPTIONS`` responses.
 
         .. versionadded:: 0.7
         """
-        methods = ctx.url_adapter.allowed_methods()  # type: ignore[union-attr]
+        adapter = request_ctx.url_adapter
+        methods = adapter.allowed_methods()  # type: ignore[union-attr]
         rv = self.response_class()
         rv.allow.update(methods)
         return rv
@@ -1156,9 +1010,11 @@ class Flask(App):
         .. versionadded:: 2.2
             Moved from ``flask.url_for``, which calls this method.
         """
-        if (ctx := _cv_app.get(None)) is not None and ctx.has_request:
-            url_adapter = ctx.url_adapter
-            blueprint_name = ctx.request.blueprint
+        req_ctx = _cv_request.get(None)
+
+        if req_ctx is not None:
+            url_adapter = req_ctx.url_adapter
+            blueprint_name = req_ctx.request.blueprint
 
             # If the endpoint starts with "." and the request matches a
             # blueprint, the endpoint is relative to the blueprint.
@@ -1173,11 +1029,13 @@ class Flask(App):
             if _external is None:
                 _external = _scheme is not None
         else:
+            app_ctx = _cv_app.get(None)
+
             # If called by helpers.url_for, an app context is active,
             # use its url_adapter. Otherwise, app.url_for was called
             # directly, build an adapter.
-            if ctx is not None:
-                url_adapter = ctx.url_adapter
+            if app_ctx is not None:
+                url_adapter = app_ctx.url_adapter
             else:
                 url_adapter = self.create_url_adapter(None)
 
@@ -1278,8 +1136,7 @@ class Flask(App):
            response object.
         """
 
-        status: int | None = None
-        headers: HeadersValue | None = None
+        status = headers = None
 
         # unpack tuple returns
         if isinstance(rv, tuple):
@@ -1291,7 +1148,7 @@ class Flask(App):
             # decide if a 2-tuple has status or headers
             elif len_rv == 2:
                 if isinstance(rv[1], (Headers, dict, tuple, list)):
-                    rv, headers = rv  # pyright: ignore
+                    rv, headers = rv
                 else:
                     rv, status = rv  # type: ignore[assignment,misc]
             # other sized tuples are not allowed
@@ -1317,7 +1174,7 @@ class Flask(App):
                 # waiting to do it manually, so that the class can handle any
                 # special logic
                 rv = self.response_class(
-                    rv,  # pyright: ignore
+                    rv,
                     status=status,
                     headers=headers,  # type: ignore[arg-type]
                 )
@@ -1359,11 +1216,11 @@ class Flask(App):
 
         # extend existing headers with provided headers
         if headers:
-            rv.headers.update(headers)
+            rv.headers.update(headers)  # type: ignore[arg-type]
 
         return rv
 
-    def preprocess_request(self, ctx: AppContext) -> ft.ResponseReturnValue | None:
+    def preprocess_request(self) -> ft.ResponseReturnValue | None:
         """Called before the request is dispatched. Calls
         :attr:`url_value_preprocessors` registered with the app and the
         current blueprint (if any). Then calls :attr:`before_request_funcs`
@@ -1373,13 +1230,12 @@ class Flask(App):
         value is handled as if it was the return value from the view, and
         further request handling is stopped.
         """
-        req = ctx.request
-        names = (None, *reversed(req.blueprints))
+        names = (None, *reversed(request.blueprints))
 
         for name in names:
             if name in self.url_value_preprocessors:
                 for url_func in self.url_value_preprocessors[name]:
-                    url_func(req.endpoint, req.view_args)
+                    url_func(request.endpoint, request.view_args)
 
         for name in names:
             if name in self.before_request_funcs:
@@ -1391,7 +1247,7 @@ class Flask(App):
 
         return None
 
-    def process_response(self, ctx: AppContext, response: Response) -> Response:
+    def process_response(self, response: Response) -> Response:
         """Can be overridden in order to modify the response object
         before it's sent to the WSGI server.  By default this will
         call all the :meth:`after_request` decorated functions.
@@ -1404,90 +1260,92 @@ class Flask(App):
         :return: a new response object or the same, has to be an
                  instance of :attr:`response_class`.
         """
+        ctx = request_ctx._get_current_object()  # type: ignore[attr-defined]
+
         for func in ctx._after_request_functions:
             response = self.ensure_sync(func)(response)
 
-        for name in chain(ctx.request.blueprints, (None,)):
+        for name in chain(request.blueprints, (None,)):
             if name in self.after_request_funcs:
                 for func in reversed(self.after_request_funcs[name]):
                     response = self.ensure_sync(func)(response)
 
-        if not self.session_interface.is_null_session(ctx._get_session()):
-            self.session_interface.save_session(self, ctx._get_session(), response)
+        if not self.session_interface.is_null_session(ctx.session):
+            self.session_interface.save_session(self, ctx.session, response)
 
         return response
 
     def do_teardown_request(
-        self, ctx: AppContext, exc: BaseException | None = None
+        self,
+        exc: BaseException | None = _sentinel,  # type: ignore[assignment]
     ) -> None:
-        """Called after the request is dispatched and the response is finalized,
-        right before the request context is popped. Called by
-        :meth:`.AppContext.pop`.
+        """Called after the request is dispatched and the response is
+        returned, right before the request context is popped.
 
-        This calls all functions decorated with :meth:`teardown_request`, and
-        :meth:`Blueprint.teardown_request` if a blueprint handled the request.
-        Finally, the :data:`request_tearing_down` signal is sent.
+        This calls all functions decorated with
+        :meth:`teardown_request`, and :meth:`Blueprint.teardown_request`
+        if a blueprint handled the request. Finally, the
+        :data:`request_tearing_down` signal is sent.
 
-        :param exc: An unhandled exception raised while dispatching the request.
-            Passed to each teardown function.
+        This is called by
+        :meth:`RequestContext.pop() <flask.ctx.RequestContext.pop>`,
+        which may be delayed during testing to maintain access to
+        resources.
 
-        .. versionchanged:: 3.2
-            All callbacks are called rather than stopping on the first error.
+        :param exc: An unhandled exception raised while dispatching the
+            request. Detected from the current exception information if
+            not passed. Passed to each teardown function.
 
         .. versionchanged:: 0.9
             Added the ``exc`` argument.
         """
-        collect_errors = _CollectErrors()
+        if exc is _sentinel:
+            exc = sys.exc_info()[1]
 
-        for name in chain(ctx.request.blueprints, (None,)):
+        for name in chain(request.blueprints, (None,)):
             if name in self.teardown_request_funcs:
                 for func in reversed(self.teardown_request_funcs[name]):
-                    with collect_errors:
-                        self.ensure_sync(func)(exc)
+                    self.ensure_sync(func)(exc)
 
-        with collect_errors:
-            request_tearing_down.send(self, _async_wrapper=self.ensure_sync, exc=exc)
-
-        collect_errors.raise_any("Errors during request teardown")
+        request_tearing_down.send(self, _async_wrapper=self.ensure_sync, exc=exc)
 
     def do_teardown_appcontext(
-        self, ctx: AppContext, exc: BaseException | None = None
+        self,
+        exc: BaseException | None = _sentinel,  # type: ignore[assignment]
     ) -> None:
-        """Called right before the application context is popped. Called by
-        :meth:`.AppContext.pop`.
+        """Called right before the application context is popped.
 
-        This calls all functions decorated with :meth:`teardown_appcontext`.
-        Then the :data:`appcontext_tearing_down` signal is sent.
+        When handling a request, the application context is popped
+        after the request context. See :meth:`do_teardown_request`.
 
-        :param exc: An unhandled exception raised while the context was active.
-            Passed to each teardown function.
+        This calls all functions decorated with
+        :meth:`teardown_appcontext`. Then the
+        :data:`appcontext_tearing_down` signal is sent.
 
-        .. versionchanged:: 3.2
-            All callbacks are called rather than stopping on the first error.
+        This is called by
+        :meth:`AppContext.pop() <flask.ctx.AppContext.pop>`.
 
         .. versionadded:: 0.9
         """
-        collect_errors = _CollectErrors()
+        if exc is _sentinel:
+            exc = sys.exc_info()[1]
 
         for func in reversed(self.teardown_appcontext_funcs):
-            with collect_errors:
-                self.ensure_sync(func)(exc)
+            self.ensure_sync(func)(exc)
 
-        with collect_errors:
-            appcontext_tearing_down.send(self, _async_wrapper=self.ensure_sync, exc=exc)
-
-        collect_errors.raise_any("Errors during app teardown")
+        appcontext_tearing_down.send(self, _async_wrapper=self.ensure_sync, exc=exc)
 
     def app_context(self) -> AppContext:
-        """Create an :class:`.AppContext`. When the context is pushed,
-        :data:`.current_app` and :data:`.g` become available.
+        """Create an :class:`~flask.ctx.AppContext`. Use as a ``with``
+        block to push the context, which will make :data:`current_app`
+        point at this application.
 
-        A context is automatically pushed when handling each request, and when
-        running any ``flask`` CLI command. Use this as a ``with`` block to
-        manually push a context outside of those situations, such as during
-        setup or testing.
+        An application context is automatically pushed by
+        :meth:`RequestContext.push() <flask.ctx.RequestContext.push>`
+        when handling a request, and when running a CLI command. Use
+        this to manually create a context outside of these situations.
 
-        .. code-block:: python
+        ::
 
             with app.app_context():
                 init_db()
@@ -1498,37 +1356,44 @@ class Flask(App):
         """
         return AppContext(self)
 
-    def request_context(self, environ: WSGIEnvironment) -> AppContext:
-        """Create an :class:`.AppContext` with request information representing
-        the given WSGI environment. A context is automatically pushed when
-        handling each request. When the context is pushed, :data:`.request`,
-        :data:`.session`, :data:`g:, and :data:`.current_app` become available.
+    def request_context(self, environ: WSGIEnvironment) -> RequestContext:
+        """Create a :class:`~flask.ctx.RequestContext` representing a
+        WSGI environment. Use a ``with`` block to push the context,
+        which will make :data:`request` point at this request.
 
-        This method should not be used in your own code. Creating a valid WSGI
-        environ is not trivial. Use :meth:`test_request_context` to correctly
-        create a WSGI environ and request context instead.
+        See :doc:`/reqcontext`.
 
-        See :doc:`/appcontext`.
+        Typically you should not call this from your own code. A request
+        context is automatically pushed by the :meth:`wsgi_app` when
+        handling a request. Use :meth:`test_request_context` to create
+        an environment and context instead of this method.
 
-        :param environ: A WSGI environment.
+        :param environ: a WSGI environment
         """
-        return AppContext.from_environ(self, environ)
+        return RequestContext(self, environ)
 
-    def test_request_context(self, *args: t.Any, **kwargs: t.Any) -> AppContext:
-        """Create an :class:`.AppContext` with request information created from
-        the given arguments. When the context is pushed, :data:`.request`,
-        :data:`.session`, :data:`g:, and :data:`.current_app` become available.
+    def test_request_context(self, *args: t.Any, **kwargs: t.Any) -> RequestContext:
+        """Create a :class:`~flask.ctx.RequestContext` for a WSGI
+        environment created from the given values. This is mostly useful
+        during testing, where you may want to run a function that uses
+        request data without dispatching a full request.
 
-        This is useful during testing to run a function that uses request data
-        without dispatching a full request. Use this as a ``with`` block to push
-        a context.
+        See :doc:`/reqcontext`.
 
-        .. code-block:: python
+        Use a ``with`` block to push the context, which will make
+        :data:`request` point at the request for the created
+        environment. ::
 
             with app.test_request_context(...):
                 generate_report()
 
-        See :doc:`/appcontext`.
+        When using the shell, it may be easier to push and pop the
+        context manually to avoid indentation. ::
+
+            ctx = app.test_request_context(...)
+            ctx.push()
+            ...
+            ctx.pop()
 
         Takes the same arguments as Werkzeug's
         :class:`~werkzeug.test.EnvironBuilder`, with some defaults from
@@ -1538,18 +1403,20 @@ class Flask(App):
         :param path: URL path being requested.
         :param base_url: Base URL where the app is being served, which
             ``path`` is relative to. If not given, built from
-            :data:`PREFERRED_URL_SCHEME`, ``subdomain``, :data:`SERVER_NAME`,
-            and :data:`APPLICATION_ROOT`.
-        :param subdomain: Subdomain name to prepend to :data:`SERVER_NAME`.
+            :data:`PREFERRED_URL_SCHEME`, ``subdomain``,
+            :data:`SERVER_NAME`, and :data:`APPLICATION_ROOT`.
+        :param subdomain: Subdomain name to append to
+            :data:`SERVER_NAME`.
         :param url_scheme: Scheme to use instead of
             :data:`PREFERRED_URL_SCHEME`.
-        :param data: The request body text or bytes,or a dict of form data.
+        :param data: The request body, either as a string or a dict of
+            form keys and values.
         :param json: If given, this is serialized as JSON and passed as
             ``data``. Also defaults ``content_type`` to
             ``application/json``.
-        :param args: Other positional arguments passed to
+        :param args: other positional arguments passed to
             :class:`~werkzeug.test.EnvironBuilder`.
-        :param kwargs: Other keyword arguments passed to
+        :param kwargs: other keyword arguments passed to
             :class:`~werkzeug.test.EnvironBuilder`.
         """
         from .testing import EnvironBuilder
@@ -1557,12 +1424,10 @@ class Flask(App):
         builder = EnvironBuilder(self, *args, **kwargs)
 
         try:
-            environ = builder.get_environ()
+            return self.request_context(builder.get_environ())
         finally:
             builder.close()
 
-        return self.request_context(environ)
-
     def wsgi_app(
         self, environ: WSGIEnvironment, start_response: StartResponse
     ) -> cabc.Iterable[bytes]:
@@ -1583,6 +1448,7 @@ class Flask(App):
             Teardown events for the request and app contexts are called
             even if an unhandled error occurs. Other events may not be
             called depending on when an error occurs during dispatch.
+            See :ref:`callbacks-and-errors`.
 
         :param environ: A WSGI environment.
         :param start_response: A callable accepting a status code,
@@ -1594,23 +1460,20 @@ class Flask(App):
         try:
             try:
                 ctx.push()
-                response = self.full_dispatch_request(ctx)
+                response = self.full_dispatch_request()
             except Exception as e:
                 error = e
-                response = self.handle_exception(ctx, e)
-            except:
+                response = self.handle_exception(e)
+            except:  # noqa: B001
                 error = sys.exc_info()[1]
                 raise
             return response(environ, start_response)
         finally:
             if "werkzeug.debug.preserve_context" in environ:
-                environ["werkzeug.debug.preserve_context"](ctx)
+                environ["werkzeug.debug.preserve_context"](_cv_app.get())
+                environ["werkzeug.debug.preserve_context"](_cv_request.get())
 
-            if (
-                error is not None
-                and self.should_ignore_error is not None
-                and self.should_ignore_error(error)
-            ):
+            if error is not None and self.should_ignore_error(error):
                 error = None
 
             ctx.pop(error)

src/flask/blueprints.py

@@ -4,54 +4,16 @@ import os
 import typing as t
 from datetime import timedelta
 
-from .cli import AppGroup
 from .globals import current_app
 from .helpers import send_from_directory
 from .sansio.blueprints import Blueprint as SansioBlueprint
 from .sansio.blueprints import BlueprintSetupState as BlueprintSetupState  # noqa
-from .sansio.scaffold import _sentinel
 
 if t.TYPE_CHECKING:  # pragma: no cover
     from .wrappers import Response
 
 
 class Blueprint(SansioBlueprint):
-    def __init__(
-        self,
-        name: str,
-        import_name: str,
-        static_folder: str | os.PathLike[str] | None = None,
-        static_url_path: str | None = None,
-        template_folder: str | os.PathLike[str] | None = None,
-        url_prefix: str | None = None,
-        subdomain: str | None = None,
-        url_defaults: dict[str, t.Any] | None = None,
-        root_path: str | None = None,
-        cli_group: str | None = _sentinel,  # type: ignore
-    ) -> None:
-        super().__init__(
-            name,
-            import_name,
-            static_folder,
-            static_url_path,
-            template_folder,
-            url_prefix,
-            subdomain,
-            url_defaults,
-            root_path,
-            cli_group,
-        )
-
-        #: The Click command group for registering CLI commands for this
-        #: object. The commands are available from the ``flask`` command
-        #: once the application has been discovered and blueprints have
-        #: been registered.
-        self.cli = AppGroup()
-
-        # Set the name of the Click group in case someone wants to add
-        # the app's commands to another CLI tool.
-        self.cli.name = self.name
-
     def get_send_file_max_age(self, filename: str | None) -> int | None:
         """Used by :func:`send_file` to determine the ``max_age`` cache
         value for a given file path if it wasn't passed.
@@ -101,28 +63,29 @@ class Blueprint(SansioBlueprint):
             t.cast(str, self.static_folder), filename, max_age=max_age
         )
 
-    def open_resource(
-        self, resource: str, mode: str = "rb", encoding: str | None = "utf-8"
-    ) -> t.IO[t.AnyStr]:
-        """Open a resource file relative to :attr:`root_path` for reading. The
-        blueprint-relative equivalent of the app's :meth:`~.Flask.open_resource`
-        method.
+    def open_resource(self, resource: str, mode: str = "rb") -> t.IO[t.AnyStr]:
+        """Open a resource file relative to :attr:`root_path` for
+        reading.
 
-        :param resource: Path to the resource relative to :attr:`root_path`.
-        :param mode: Open the file in this mode. Only reading is supported,
-            valid values are ``"r"`` (or ``"rt"``) and ``"rb"``.
-        :param encoding: Open the file with this encoding when opening in text
-            mode. This is ignored when opening in binary mode.
+        For example, if the file ``schema.sql`` is next to the file
+        ``app.py`` where the ``Flask`` app is defined, it can be opened
+        with:
+
+        .. code-block:: python
+
+            with app.open_resource("schema.sql") as f:
+                conn.executescript(f.read())
+
+        :param resource: Path to the resource relative to
+            :attr:`root_path`.
+        :param mode: Open the file in this mode. Only reading is
+            supported, valid values are "r" (or "rt") and "rb".
+
+        Note this is a duplicate of the same method in the Flask
+        class.
 
-        .. versionchanged:: 3.1
-            Added the ``encoding`` parameter.
         """
         if mode not in {"r", "rt", "rb"}:
             raise ValueError("Resources can only be opened for reading.")
 
-        path = os.path.join(self.root_path, resource)
-
-        if mode == "rb":
-            return open(path, mode)  # pyright: ignore
-
-        return open(path, mode, encoding=encoding)
+        return open(os.path.join(self.root_path, resource), mode)

src/flask/cli.py

@@ -229,13 +229,15 @@ def prepare_import(path: str) -> str:
 @t.overload
 def locate_app(
     module_name: str, app_name: str | None, raise_if_not_found: t.Literal[True] = True
-) -> Flask: ...
+) -> Flask:
+    ...
 
 
 @t.overload
 def locate_app(
     module_name: str, app_name: str | None, raise_if_not_found: t.Literal[False] = ...
-) -> Flask | None: ...
+) -> Flask | None:
+    ...
 
 
 def locate_app(
@@ -297,9 +299,6 @@ class ScriptInfo:
     a bigger role.  Typically it's created automatically by the
     :class:`FlaskGroup` but you can also manually create it and pass it
     onwards as click object.
-
-    .. versionchanged:: 3.1
-        Added the ``load_dotenv_defaults`` parameter and attribute.
     """
 
     def __init__(
@@ -307,7 +306,6 @@ class ScriptInfo:
         app_import_path: str | None = None,
         create_app: t.Callable[..., Flask] | None = None,
         set_debug_flag: bool = True,
-        load_dotenv_defaults: bool = True,
     ) -> None:
         #: Optionally the import path for the Flask application.
         self.app_import_path = app_import_path
@@ -318,16 +316,6 @@ class ScriptInfo:
         #: this script info.
         self.data: dict[t.Any, t.Any] = {}
         self.set_debug_flag = set_debug_flag
-
-        self.load_dotenv_defaults = get_load_dotenv(load_dotenv_defaults)
-        """Whether default ``.flaskenv`` and ``.env`` files should be loaded.
-
-        ``ScriptInfo`` doesn't load anything, this is for reference when doing
-        the load elsewhere during processing.
-
-        .. versionadded:: 3.1
-        """
-
         self._loaded_app: Flask | None = None
 
     def load_app(self) -> Flask:
@@ -337,9 +325,9 @@ class ScriptInfo:
         """
         if self._loaded_app is not None:
             return self._loaded_app
-        app: Flask | None = None
+
         if self.create_app is not None:
-            app = self.create_app()
+            app: Flask | None = self.create_app()
         else:
             if self.app_import_path:
                 path, name = (
@@ -468,7 +456,7 @@ _app_option = click.Option(
 def _set_debug(ctx: click.Context, param: click.Option, value: bool) -> bool | None:
     # If the flag isn't provided, it will default to False. Don't use
     # that, let debug be set by env in that case.
-    source = ctx.get_parameter_source(param.name)
+    source = ctx.get_parameter_source(param.name)  # type: ignore[arg-type]
 
     if source is not None and source in (
         ParameterSource.DEFAULT,
@@ -493,22 +481,23 @@ _debug_option = click.Option(
 def _env_file_callback(
     ctx: click.Context, param: click.Option, value: str | None
 ) -> str | None:
+    if value is None:
+        return None
+
+    import importlib
+
     try:
-        import dotenv  # noqa: F401
+        importlib.import_module("dotenv")
     except ImportError:
-        # Only show an error if a value was passed, otherwise we still want to
-        # call load_dotenv and show a message without exiting.
-        if value is not None:
-            raise click.BadParameter(
-                "python-dotenv must be installed to load an env file.",
-                ctx=ctx,
-                param=param,
-            ) from None
-
-    # Load if a value was passed, or we want to load default files, or both.
-    if value is not None or ctx.obj.load_dotenv_defaults:
-        load_dotenv(value, load_defaults=ctx.obj.load_dotenv_defaults)
+        raise click.BadParameter(
+            "python-dotenv must be installed to load an env file.",
+            ctx=ctx,
+            param=param,
+        ) from None
 
+    # Don't check FLASK_SKIP_DOTENV, that only disables automatically
+    # loading .env and .flaskenv files.
+    load_dotenv(value)
     return value
 
 
@@ -517,11 +506,7 @@ def _env_file_callback(
 _env_file_option = click.Option(
     ["-e", "--env-file"],
     type=click.Path(exists=True, dir_okay=False),
-    help=(
-        "Load environment variables from this file, taking precedence over"
-        " those set by '.env' and '.flaskenv'. Variables set directly in the"
-        " environment take highest precedence. python-dotenv must be installed."
-    ),
+    help="Load environment variables from this file. python-dotenv must be installed.",
     is_eager=True,
     expose_value=False,
     callback=_env_file_callback,
@@ -545,9 +530,6 @@ class FlaskGroup(AppGroup):
         directory to the directory containing the first file found.
     :param set_debug_flag: Set the app's debug flag.
 
-    .. versionchanged:: 3.1
-        ``-e path`` takes precedence over default ``.env`` and ``.flaskenv`` files.
-
     .. versionchanged:: 2.2
         Added the ``-A/--app``, ``--debug/--no-debug``, ``-e/--env-file`` options.
 
@@ -569,7 +551,7 @@ class FlaskGroup(AppGroup):
         set_debug_flag: bool = True,
         **extra: t.Any,
     ) -> None:
-        params: list[click.Parameter] = list(extra.pop("params", None) or ())
+        params = list(extra.pop("params", None) or ())
         # Processing is done with option callbacks instead of a group
         # callback. This allows users to make a custom group callback
         # without losing the behavior. --env-file must come first so
@@ -601,7 +583,15 @@ class FlaskGroup(AppGroup):
         if self._loaded_plugin_commands:
             return
 
-        for ep in importlib.metadata.entry_points(group="flask.commands"):
+        if sys.version_info >= (3, 10):
+            from importlib import metadata
+        else:
+            # Use a backport on Python < 3.10. We technically have
+            # importlib.metadata on 3.8+, but the API changed in 3.10,
+            # so use the backport for consistency.
+            import importlib_metadata as metadata
+
+        for ep in metadata.entry_points(group="flask.commands"):
             self.add_command(ep.load(), ep.name)
 
         self._loaded_plugin_commands = True
@@ -628,7 +618,7 @@ class FlaskGroup(AppGroup):
         # Push an app context for the loaded app unless it is already
         # active somehow. This makes the context available to parameter
         # and command callbacks without needing @with_appcontext.
-        if not current_app or current_app._get_current_object() is not app:
+        if not current_app or current_app._get_current_object() is not app:  # type: ignore[attr-defined]
             ctx.with_resource(app.app_context())
 
         return app.cli.get_command(ctx, name)
@@ -666,19 +656,20 @@ class FlaskGroup(AppGroup):
         # when importing, blocking whatever command is being called.
         os.environ["FLASK_RUN_FROM_CLI"] = "true"
 
+        # Attempt to load .env and .flask env files. The --env-file
+        # option can cause another file to be loaded.
+        if get_load_dotenv(self.load_dotenv):
+            load_dotenv()
+
         if "obj" not in extra and "obj" not in self.context_settings:
             extra["obj"] = ScriptInfo(
-                create_app=self.create_app,
-                set_debug_flag=self.set_debug_flag,
-                load_dotenv_defaults=self.load_dotenv,
+                create_app=self.create_app, set_debug_flag=self.set_debug_flag
             )
 
         return super().make_context(info_name, args, parent=parent, **extra)
 
     def parse_args(self, ctx: click.Context, args: list[str]) -> list[str]:
-        if (not args and self.no_args_is_help) or (
-            len(args) == 1 and args[0] in self.get_help_option_names(ctx)
-        ):
+        if not args and self.no_args_is_help:
             # Attempt to load --env-file and --app early in case they
             # were given as env vars. Otherwise no_args_is_help will not
             # see commands from app.cli.
@@ -695,26 +686,18 @@ def _path_is_ancestor(path: str, other: str) -> bool:
     return os.path.join(path, other[len(path) :].lstrip(os.sep)) == other
 
 
-def load_dotenv(
-    path: str | os.PathLike[str] | None = None, load_defaults: bool = True
-) -> bool:
-    """Load "dotenv" files to set environment variables. A given path takes
-    precedence over ``.env``, which takes precedence over ``.flaskenv``. After
-    loading and combining these files, values are only set if the key is not
-    already set in ``os.environ``.
+def load_dotenv(path: str | os.PathLike[str] | None = None) -> bool:
+    """Load "dotenv" files in order of precedence to set environment variables.
+
+    If an env var is already set it is not overwritten, so earlier files in the
+    list are preferred over later files.
 
     This is a no-op if `python-dotenv`_ is not installed.
 
     .. _python-dotenv: https://github.com/theskumar/python-dotenv#readme
 
-    :param path: Load the file at this location.
-    :param load_defaults: Search for and load the default ``.flaskenv`` and
-        ``.env`` files.
-    :return: ``True`` if at least one env var was loaded.
-
-    .. versionchanged:: 3.1
-        Added the ``load_defaults`` parameter. A given path takes precedence
-        over default files.
+    :param path: Load the file at this location instead of searching.
+    :return: ``True`` if a file was loaded.
 
     .. versionchanged:: 2.0
         The current directory is not changed to the location of the
@@ -734,33 +717,34 @@ def load_dotenv(
     except ImportError:
         if path or os.path.isfile(".env") or os.path.isfile(".flaskenv"):
             click.secho(
-                " * Tip: There are .env files present. Install python-dotenv"
-                " to use them.",
+                " * Tip: There are .env or .flaskenv files present."
+                ' Do "pip install python-dotenv" to use them.',
                 fg="yellow",
                 err=True,
             )
 
         return False
 
-    data: dict[str, str | None] = {}
+    # Always return after attempting to load a given path, don't load
+    # the default files.
+    if path is not None:
+        if os.path.isfile(path):
+            return dotenv.load_dotenv(path, encoding="utf-8")
 
-    if load_defaults:
-        for default_name in (".flaskenv", ".env"):
-            if not (default_path := dotenv.find_dotenv(default_name, usecwd=True)):
-                continue
+        return False
 
-            data |= dotenv.dotenv_values(default_path, encoding="utf-8")
+    loaded = False
 
-    if path is not None and os.path.isfile(path):
-        data |= dotenv.dotenv_values(path, encoding="utf-8")
+    for name in (".env", ".flaskenv"):
+        path = dotenv.find_dotenv(name, usecwd=True)
 
-    for key, value in data.items():
-        if key in os.environ or value is None:
+        if not path:
             continue
 
-        os.environ[key] = value
+        dotenv.load_dotenv(path, encoding="utf-8")
+        loaded = True
 
-    return bool(data)  # True if at least one env var was loaded.
+    return loaded  # True if at least one file was located and loaded.
 
 
 def show_server_banner(debug: bool, app_import_path: str | None) -> None:
@@ -777,7 +761,7 @@ def show_server_banner(debug: bool, app_import_path: str | None) -> None:
         click.echo(f" * Debug mode: {'on' if debug else 'off'}")
 
 
-class CertParamType(click.ParamType[t.Any]):
+class CertParamType(click.ParamType):
     """Click option type for the ``--cert`` option. Allows either an
     existing file, the string ``'adhoc'``, or an import for a
     :class:`~ssl.SSLContext` object.
@@ -803,7 +787,7 @@ class CertParamType(click.ParamType[t.Any]):
         try:
             return self.path_type(value, param, ctx)
         except click.BadParameter:
-            value = click.STRING(value, param, ctx).lower()  # type: ignore[union-attr]
+            value = click.STRING(value, param, ctx).lower()
 
             if value == "adhoc":
                 try:
@@ -874,9 +858,7 @@ class SeparatedPathType(click.Path):
         self, value: t.Any, param: click.Parameter | None, ctx: click.Context | None
     ) -> t.Any:
         items = self.split_envvar_value(value)
-        # can't call no-arg super() inside list comprehension until Python 3.12
-        super_convert = super().convert
-        return [super_convert(item, param, ctx) for item in items]
+        return [super().convert(item, param, ctx) for item in items]
 
 
 @click.command("run", short_help="Run a development server.")
@@ -952,7 +934,7 @@ def run_command(
     option.
     """
     try:
-        app: WSGIApplication = info.load_app()  # pyright: ignore
+        app: WSGIApplication = info.load_app()
     except Exception as e:
         if is_running_from_reloader():
             # When reloading, print out the error immediately, but raise

src/flask/config.py

@@ -27,10 +27,12 @@ class ConfigAttribute(t.Generic[T]):
         self.get_converter = get_converter
 
     @t.overload
-    def __get__(self, obj: None, owner: None) -> te.Self: ...
+    def __get__(self, obj: None, owner: None) -> te.Self:
+        ...
 
     @t.overload
-    def __get__(self, obj: App, owner: type[App]) -> T: ...
+    def __get__(self, obj: App, owner: type[App]) -> T:
+        ...
 
     def __get__(self, obj: App | None, owner: type[App] | None = None) -> T | te.Self:
         if obj is None:
@@ -150,13 +152,13 @@ class Config(dict):  # type: ignore[type-arg]
         .. versionadded:: 2.1
         """
         prefix = f"{prefix}_"
+        len_prefix = len(prefix)
 
         for key in sorted(os.environ):
             if not key.startswith(prefix):
                 continue
 
             value = os.environ[key]
-            key = key.removeprefix(prefix)
 
             try:
                 value = loads(value)
@@ -164,6 +166,9 @@ class Config(dict):  # type: ignore[type-arg]
                 # Keep the value as a string if loading failed.
                 pass
 
+            # Change to key.removeprefix(prefix) on Python >= 3.9.
+            key = key[len_prefix:]
+
             if "__" not in key:
                 # A non-nested key, set directly.
                 self[key] = value