update changes.rst

.pre-commit-config.yaml

@@ -2,7 +2,7 @@ ci:
   autoupdate_schedule: monthly
 repos:
   - repo: https://github.com/asottile/pyupgrade
-    rev: v2.25.0
+    rev: v2.29.0
     hooks:
       - id: pyupgrade
         args: ["--py36-plus"]
@@ -14,7 +14,7 @@ repos:
         files: "^(?!examples/)"
         args: ["--application-directories", "src"]
   - repo: https://github.com/psf/black
-    rev: 21.8b0
+    rev: 21.9b0
     hooks:
       - id: black
   - repo: https://github.com/PyCQA/flake8

CHANGES.rst

@@ -3,7 +3,7 @@
 Version 2.0.2
 -------------
 
-Unreleased
+Released 2021-10-04
 
 -   Fix type annotation for ``teardown_*`` methods. :issue:`4093`
 -   Fix type annotation for ``before_request`` and ``before_app_request``
@@ -21,6 +21,9 @@ Unreleased
     :issue:`4096`
 -   The CLI loader handles ``**kwargs`` in a ``create_app`` function.
     :issue:`4170`
+-   Fix the order of ``before_request`` and other callbacks that trigger
+    before the view returns. They are called from the app down to the
+    closest nested blueprint. :issue:`4229`
 -   Fix Unable to extend FlaskClient with follow_redirects. :issue:`3396`
 
 Version 2.0.1

artwork/LICENSE.rst

@@ -10,7 +10,7 @@ following conditions are met:
 1.  Redistributions of source code must retain the above copyright
     notice and this list of conditions.
 
-3.  Neither the name of the copyright holder nor the names of its
+2.  Neither the name of the copyright holder nor the names of its
     contributors may be used to endorse or promote products derived from
     this software without specific prior written permission.
 

docs/appcontext.rst

@@ -8,7 +8,7 @@ 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 the :doc:`/reqcontext`, which keeps track of
+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.
 

docs/debugging.rst

@@ -69,7 +69,7 @@ enables the debugger and reloader.
 
 ``FLASK_ENV`` can only be set as an environment variable. When running
 from Python code, passing ``debug=True`` enables debug mode, which is
-mostly equivalent. Debug mode can be controled separately from
+mostly equivalent. Debug mode can be controlled separately from
 ``FLASK_ENV`` with the ``FLASK_DEBUG`` environment variable as well.
 
 .. code-block:: python

docs/patterns/wtforms.rst

@@ -19,7 +19,7 @@ forms.
    fun.  You can get it from `PyPI
    <https://pypi.org/project/Flask-WTF/>`_.
 
-.. _Flask-WTF: https://flask-wtf.readthedocs.io/en/stable/
+.. _Flask-WTF: https://flask-wtf.readthedocs.io/
 
 The Forms
 ---------

docs/reqcontext.rst

@@ -8,7 +8,7 @@ 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 the :doc:`/appcontext`, which keeps track of the
+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.
 
@@ -33,8 +33,8 @@ Lifetime of the Context
 -----------------------
 
 When a Flask application begins handling a request, it pushes a request
-context, which also pushes an :doc:`/appcontext`. When the request ends
+context, which also pushes an :doc:`app context </appcontext>`. When the
-it pops the request context then the application context.
+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

docs/shell.rst

@@ -21,8 +21,7 @@ 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 the :doc:`reqcontext`
+Generally it's recommended that you read :doc:`reqcontext` first.
-chapter of the documentation first.
 
 Command Line Interface
 ----------------------

requirements/dev.txt

@@ -22,25 +22,25 @@ cffi==1.14.6
     # via cryptography
 cfgv==3.3.1
     # via pre-commit
-charset-normalizer==2.0.4
+charset-normalizer==2.0.6
     # via requests
 click==8.0.1
     # via pip-tools
-cryptography==3.4.8
+cryptography==35.0.0
     # via -r requirements/typing.in
-distlib==0.3.2
+distlib==0.3.3
     # via virtualenv
 docutils==0.16
     # via
     #   sphinx
     #   sphinx-tabs
-filelock==3.0.12
+filelock==3.2.0
     # via
     #   tox
     #   virtualenv
-greenlet==1.1.1
+greenlet==1.1.2
     # via -r requirements/tests.in
-identify==2.2.13
+identify==2.2.15
     # via pre-commit
 idna==3.2
     # via requests
@@ -68,9 +68,9 @@ pallets-sphinx-themes==2.0.1
     # via -r requirements/docs.in
 pep517==0.11.0
     # via pip-tools
-pip-tools==6.2.0
+pip-tools==6.3.0
     # via -r requirements/dev.in
-platformdirs==2.3.0
+platformdirs==2.4.0
     # via virtualenv
 pluggy==1.0.0
     # via
@@ -106,7 +106,7 @@ six==1.16.0
     #   virtualenv
 snowballstemmer==2.1.0
     # via sphinx
-sphinx==4.1.2
+sphinx==4.2.0
     # via
     #   -r requirements/docs.in
     #   pallets-sphinx-themes
@@ -139,19 +139,19 @@ toml==0.10.2
     #   tox
 tomli==1.2.1
     # via pep517
-tox==3.24.3
+tox==3.24.4
     # via -r requirements/dev.in
 types-contextvars==0.1.4
     # via -r requirements/typing.in
 types-dataclasses==0.1.7
     # via -r requirements/typing.in
-types-setuptools==57.0.2
+types-setuptools==57.4.0
     # via -r requirements/typing.in
 typing-extensions==3.10.0.2
     # via mypy
-urllib3==1.26.6
+urllib3==1.26.7
     # via requests
-virtualenv==20.7.2
+virtualenv==20.8.1
     # via
     #   pre-commit
     #   tox

requirements/docs.txt

@@ -10,7 +10,7 @@ babel==2.9.1
     # via sphinx
 certifi==2021.5.30
     # via requests
-charset-normalizer==2.0.4
+charset-normalizer==2.0.6
     # via requests
 docutils==0.16
     # via
@@ -42,7 +42,7 @@ requests==2.26.0
     # via sphinx
 snowballstemmer==2.1.0
     # via sphinx
-sphinx==4.1.2
+sphinx==4.2.0
     # via
     #   -r requirements/docs.in
     #   pallets-sphinx-themes
@@ -67,7 +67,7 @@ sphinxcontrib-qthelp==1.0.3
     # via sphinx
 sphinxcontrib-serializinghtml==1.1.5
     # via sphinx
-urllib3==1.26.6
+urllib3==1.26.7
     # via requests
 
 # The following packages are considered to be unsafe in a requirements file:

requirements/tests.txt

@@ -10,7 +10,7 @@ attrs==21.2.0
     # via pytest
 blinker==1.4
     # via -r requirements/tests.in
-greenlet==1.1.1
+greenlet==1.1.2
     # via -r requirements/tests.in
 iniconfig==1.1.1
     # via pytest

requirements/typing.txt

@@ -6,7 +6,7 @@
 #
 cffi==1.14.6
     # via cryptography
-cryptography==3.4.8
+cryptography==35.0.0
     # via -r requirements/typing.in
 mypy==0.910
     # via -r requirements/typing.in
@@ -20,7 +20,7 @@ types-contextvars==0.1.4
     # via -r requirements/typing.in
 types-dataclasses==0.1.7
     # via -r requirements/typing.in
-types-setuptools==57.0.2
+types-setuptools==57.4.0
     # via -r requirements/typing.in
 typing-extensions==3.10.0.2
     # via mypy

src/flask/__init__.py

@@ -43,4 +43,4 @@ from .signals import template_rendered as template_rendered
 from .templating import render_template as render_template
 from .templating import render_template_string as render_template_string
 
-__version__ = "2.0.2.dev0"
+__version__ = "2.0.2"

src/flask/app.py

@@ -58,17 +58,12 @@ from .signals import request_started
 from .signals import request_tearing_down
 from .templating import DispatchingJinjaLoader
 from .templating import Environment
-from .typing import AfterRequestCallable
 from .typing import BeforeFirstRequestCallable
-from .typing import BeforeRequestCallable
 from .typing import ResponseReturnValue
 from .typing import TeardownCallable
-from .typing import TemplateContextProcessorCallable
 from .typing import TemplateFilterCallable
 from .typing import TemplateGlobalCallable
 from .typing import TemplateTestCallable
-from .typing import URLDefaultCallable
-from .typing import URLValuePreprocessorCallable
 from .wrappers import Request
 from .wrappers import Response
 
@@ -366,7 +361,8 @@ class Flask(Scaffold):
     #: .. versionadded:: 1.1.0
     url_map_class = Map
 
-    #: the test client that is used with when `test_client` is used.
+    #: The :meth:`test_client` method creates an instance of this test
+    #: client class. Defaults to :class:`~flask.testing.FlaskClient`.
     #:
     #: .. versionadded:: 0.7
     test_client_class: t.Optional[t.Type["FlaskClient"]] = None
@@ -744,20 +740,21 @@ class Flask(Scaffold):
         :param context: the context as a dictionary that is updated in place
                         to add extra variables.
         """
-        funcs: t.Iterable[
+        names: t.Iterable[t.Optional[str]] = (None,)
-            TemplateContextProcessorCallable
+
-        ] = self.template_context_processors[None]
+        # A template may be rendered outside a request context.
-        reqctx = _request_ctx_stack.top
+        if request:
-        if reqctx is not None:
+            names = chain(names, reversed(request.blueprints))
-            for bp in request.blueprints:
+
-                if bp in self.template_context_processors:
+        # The values passed to render_template take precedence. Keep a
-                    funcs = chain(funcs, self.template_context_processors[bp])
+        # copy to re-apply after all context functions.
         orig_ctx = context.copy()
-        for func in funcs:
+
-            context.update(func())
+        for name in names:
-        # make sure the original values win.  This makes it possible to
+            if name in self.template_context_processors:
-        # easier add new variables in context processors without breaking
+                for func in self.template_context_processors[name]:
-        # existing views.
+                    context.update(func())
+
         context.update(orig_ctx)
 
     def make_shell_context(self) -> dict:
@@ -1277,9 +1274,10 @@ class Flask(Scaffold):
         class, or ``None`` if a suitable handler is not found.
         """
         exc_class, code = self._get_exc_class_and_code(type(e))
+        names = (*request.blueprints, None)
 
-        for c in [code, None] if code is not None else [None]:
+        for c in (code, None) if code is not None else (None,):
-            for name in chain(request.blueprints, [None]):
+            for name in names:
                 handler_map = self.error_handler_spec[name][c]
 
                 if not handler_map:
@@ -1621,7 +1619,7 @@ class Flask(Scaffold):
         except ImportError:
             raise RuntimeError(
                 "Install Flask with the 'async' extra in order to use async views."
-            )
+            ) from None
 
         # Check that Werkzeug isn't using its fallback ContextVar class.
         if ContextVar.__module__ == "werkzeug.local":
@@ -1727,7 +1725,7 @@ class Flask(Scaffold):
                         " response. The return type must be a string,"
                         " dict, tuple, Response instance, or WSGI"
                         f" callable, but it was a {type(rv).__name__}."
-                    ).with_traceback(sys.exc_info()[2])
+                    ).with_traceback(sys.exc_info()[2]) from None
             else:
                 raise TypeError(
                     "The view function did not return a valid"
@@ -1799,17 +1797,19 @@ class Flask(Scaffold):
 
         .. versionadded:: 0.7
         """
-        funcs: t.Iterable[URLDefaultCallable] = self.url_default_functions[None]
+        names: t.Iterable[t.Optional[str]] = (None,)
 
+        # url_for may be called outside a request context, parse the
+        # passed endpoint instead of using request.blueprints.
         if "." in endpoint:
-            # This is called by url_for, which can be called outside a
+            names = chain(
-            # request, can't use request.blueprints.
+                names, reversed(_split_blueprint_path(endpoint.rpartition(".")[0]))
-            bps = _split_blueprint_path(endpoint.rpartition(".")[0])
+            )
-            bp_funcs = chain.from_iterable(self.url_default_functions[bp] for bp in bps)
-            funcs = chain(funcs, bp_funcs)
 
-        for func in funcs:
+        for name in names:
-            func(endpoint, values)
+            if name in self.url_default_functions:
+                for func in self.url_default_functions[name]:
+                    func(endpoint, values)
 
     def handle_url_build_error(
         self, error: Exception, endpoint: str, values: dict
@@ -1844,24 +1844,20 @@ class Flask(Scaffold):
         value is handled as if it was the return value from the view, and
         further request handling is stopped.
         """
+        names = (None, *reversed(request.blueprints))
 
-        funcs: t.Iterable[URLValuePreprocessorCallable] = self.url_value_preprocessors[
+        for name in names:
-            None
+            if name in self.url_value_preprocessors:
-        ]
+                for url_func in self.url_value_preprocessors[name]:
-        for bp in request.blueprints:
+                    url_func(request.endpoint, request.view_args)
-            if bp in self.url_value_preprocessors:
-                funcs = chain(funcs, self.url_value_preprocessors[bp])
-        for func in funcs:
-            func(request.endpoint, request.view_args)
 
-        funcs: t.Iterable[BeforeRequestCallable] = self.before_request_funcs[None]
+        for name in names:
-        for bp in request.blueprints:
+            if name in self.before_request_funcs:
-            if bp in self.before_request_funcs:
+                for before_func in self.before_request_funcs[name]:
-                funcs = chain(funcs, self.before_request_funcs[bp])
+                    rv = self.ensure_sync(before_func)()
-        for func in funcs:
+
-            rv = self.ensure_sync(func)()
+                    if rv is not None:
-            if rv is not None:
+                        return rv
-                return rv
 
         return None
 
@@ -1879,16 +1875,18 @@ class Flask(Scaffold):
                  instance of :attr:`response_class`.
         """
         ctx = _request_ctx_stack.top
-        funcs: t.Iterable[AfterRequestCallable] = ctx._after_request_functions
+
-        for bp in request.blueprints:
+        for func in ctx._after_request_functions:
-            if bp in self.after_request_funcs:
+            response = self.ensure_sync(func)(response)
-                funcs = chain(funcs, reversed(self.after_request_funcs[bp]))
+
-        if None in self.after_request_funcs:
+        for name in chain(request.blueprints, (None,)):
-            funcs = chain(funcs, reversed(self.after_request_funcs[None]))
+            if name in self.after_request_funcs:
-        for handler in funcs:
+                for func in reversed(self.after_request_funcs[name]):
-            response = self.ensure_sync(handler)(response)
+                    response = self.ensure_sync(func)(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(
@@ -1916,14 +1914,12 @@ class Flask(Scaffold):
         """
         if exc is _sentinel:
             exc = sys.exc_info()[1]
-        funcs: t.Iterable[TeardownCallable] = reversed(
+
-            self.teardown_request_funcs[None]
+        for name in chain(request.blueprints, (None,)):
-        )
+            if name in self.teardown_request_funcs:
-        for bp in request.blueprints:
+                for func in reversed(self.teardown_request_funcs[name]):
-            if bp in self.teardown_request_funcs:
+                    self.ensure_sync(func)(exc)
-                funcs = chain(funcs, reversed(self.teardown_request_funcs[bp]))
+
-        for func in funcs:
-            self.ensure_sync(func)(exc)
         request_tearing_down.send(self, exc=exc)
 
     def do_teardown_appcontext(
@@ -1945,8 +1941,10 @@ class Flask(Scaffold):
         """
         if exc is _sentinel:
             exc = sys.exc_info()[1]
+
         for func in reversed(self.teardown_appcontext_funcs):
             self.ensure_sync(func)(exc)
+
         appcontext_tearing_down.send(self, exc=exc)
 
     def app_context(self) -> AppContext:

src/flask/cli.py

@@ -69,15 +69,16 @@ def find_best_app(script_info, module):
 
                 if isinstance(app, Flask):
                     return app
-            except TypeError:
+            except TypeError as e:
                 if not _called_with_wrong_args(app_factory):
                     raise
+
                 raise NoAppException(
                     f"Detected factory {attr_name!r} in module {module.__name__!r},"
                     " but could not call it without arguments. Use"
                     f" \"FLASK_APP='{module.__name__}:{attr_name}(args)'\""
                     " to specify arguments."
-                )
+                ) from e
 
     raise NoAppException(
         "Failed to find Flask application or factory in module"
@@ -161,7 +162,7 @@ def find_app_by_string(script_info, module, app_name):
     except SyntaxError:
         raise NoAppException(
             f"Failed to parse {app_name!r} as an attribute name or function call."
-        )
+        ) from None
 
     if isinstance(expr, ast.Name):
         name = expr.id
@@ -184,7 +185,7 @@ def find_app_by_string(script_info, module, app_name):
             # message with the full expression instead.
             raise NoAppException(
                 f"Failed to parse arguments as literal values: {app_name!r}."
-            )
+            ) from None
     else:
         raise NoAppException(
             f"Failed to parse {app_name!r} as an attribute name or function call."
@@ -192,17 +193,17 @@ def find_app_by_string(script_info, module, app_name):
 
     try:
         attr = getattr(module, name)
-    except AttributeError:
+    except AttributeError as e:
         raise NoAppException(
             f"Failed to find attribute {name!r} in {module.__name__!r}."
-        )
+        ) from e
 
     # If the attribute is a function, call it with any args and kwargs
     # to get the real application.
     if inspect.isfunction(attr):
         try:
             app = call_factory(script_info, attr, args, kwargs)
-        except TypeError:
+        except TypeError as e:
             if not _called_with_wrong_args(attr):
                 raise
 
@@ -210,7 +211,7 @@ def find_app_by_string(script_info, module, app_name):
                 f"The factory {app_name!r} in module"
                 f" {module.__name__!r} could not be called with the"
                 " specified arguments."
-            )
+            ) from e
     else:
         app = attr
 
@@ -257,16 +258,15 @@ def locate_app(script_info, module_name, app_name, raise_if_not_found=True):
 
     try:
         __import__(module_name)
-    except ImportError:
+    except ImportError as e:
         # Reraise the ImportError if it occurred within the imported module.
         # Determine this by checking whether the trace has a depth > 1.
         if sys.exc_info()[2].tb_next:
             raise NoAppException(
-                f"While importing {module_name!r}, an ImportError was"
+                f"While importing {module_name!r}, an ImportError was raised."
-                f" raised:\n\n{traceback.format_exc()}"
+            ) from e
-            )
         elif raise_if_not_found:
-            raise NoAppException(f"Could not import {module_name!r}.")
+            raise NoAppException(f"Could not import {module_name!r}.") from e
         else:
             return
 
@@ -725,7 +725,7 @@ class CertParamType(click.ParamType):
                         "Using ad-hoc certificates requires the cryptography library.",
                         ctx,
                         param,
-                    )
+                    ) from None
 
                 return value
 

src/flask/debughelpers.py

@@ -83,10 +83,11 @@ def attach_enctype_error_multidict(request):
         def __getitem__(self, key):
             try:
                 return oldcls.__getitem__(self, key)
-            except KeyError:
+            except KeyError as e:
                 if key not in request.form:
                     raise
-                raise DebugFilesKeyError(request, key)
+
+                raise DebugFilesKeyError(request, key) from e
 
     newcls.__name__ = oldcls.__name__
     newcls.__module__ = oldcls.__module__

src/flask/scaffold.py

@@ -715,7 +715,7 @@ class Scaffold:
                 f"'{code_or_exception}' is not a recognized HTTP error"
                 " code. Use a subclass of HTTPException with that code"
                 " instead."
-            )
+            ) from None
 
         self.error_handler_spec[None][code][exc_class] = t.cast(
             "ErrorHandlerCallable[Exception]", f

src/flask/signals.py

@@ -29,7 +29,7 @@ except ImportError:
             raise RuntimeError(
                 "Signalling support is unavailable because the blinker"
                 " library is not installed."
-            )
+            ) from None
 
         connect = connect_via = connected_to = temporarily_connected_to = _fail
         disconnect = _fail

tests/test_blueprints.py

@@ -837,6 +837,86 @@ def test_nested_blueprint(app, client):
     assert client.get("/parent/child/grandchild/no").data == b"Grandchild no"
 
 
+def test_nested_callback_order(app, client):
+    parent = flask.Blueprint("parent", __name__)
+    child = flask.Blueprint("child", __name__)
+
+    @app.before_request
+    def app_before1():
+        flask.g.setdefault("seen", []).append("app_1")
+
+    @app.teardown_request
+    def app_teardown1(e=None):
+        assert flask.g.seen.pop() == "app_1"
+
+    @app.before_request
+    def app_before2():
+        flask.g.setdefault("seen", []).append("app_2")
+
+    @app.teardown_request
+    def app_teardown2(e=None):
+        assert flask.g.seen.pop() == "app_2"
+
+    @app.context_processor
+    def app_ctx():
+        return dict(key="app")
+
+    @parent.before_request
+    def parent_before1():
+        flask.g.setdefault("seen", []).append("parent_1")
+
+    @parent.teardown_request
+    def parent_teardown1(e=None):
+        assert flask.g.seen.pop() == "parent_1"
+
+    @parent.before_request
+    def parent_before2():
+        flask.g.setdefault("seen", []).append("parent_2")
+
+    @parent.teardown_request
+    def parent_teardown2(e=None):
+        assert flask.g.seen.pop() == "parent_2"
+
+    @parent.context_processor
+    def parent_ctx():
+        return dict(key="parent")
+
+    @child.before_request
+    def child_before1():
+        flask.g.setdefault("seen", []).append("child_1")
+
+    @child.teardown_request
+    def child_teardown1(e=None):
+        assert flask.g.seen.pop() == "child_1"
+
+    @child.before_request
+    def child_before2():
+        flask.g.setdefault("seen", []).append("child_2")
+
+    @child.teardown_request
+    def child_teardown2(e=None):
+        assert flask.g.seen.pop() == "child_2"
+
+    @child.context_processor
+    def child_ctx():
+        return dict(key="child")
+
+    @child.route("/a")
+    def a():
+        return ", ".join(flask.g.seen)
+
+    @child.route("/b")
+    def b():
+        return flask.render_template_string("{{ key }}")
+
+    parent.register_blueprint(child)
+    app.register_blueprint(parent)
+    assert (
+        client.get("/a").data == b"app_1, app_2, parent_1, parent_2, child_1, child_2"
+    )
+    assert client.get("/b").data == b"child"
+
+
 @pytest.mark.parametrize(
     "parent_init, child_init, parent_registration, child_registration",
     [

tests/test_cli.py

@@ -1,6 +1,7 @@
 # This file was part of Flask-CLI and was modified under the terms of
 # its Revised BSD License. Copyright © 2015 CERN.
 import os
+import platform
 import ssl
 import sys
 import types
@@ -320,6 +321,7 @@ def test_scriptinfo(test_apps, monkeypatch):
     assert app.name == "testapp"
 
 
+@pytest.mark.xfail(platform.python_implementation() == "PyPy", reason="flaky on pypy")
 def test_lazy_load_error(monkeypatch):
     """When using lazy loading, the correct exception should be
     re-raised.
@@ -334,7 +336,9 @@ def test_lazy_load_error(monkeypatch):
     lazy = DispatchingApp(bad_load, use_eager_loading=False)
 
     with pytest.raises(BadExc):
-        lazy._flush_bg_loading_exception()
+        # reduce flakiness by waiting for the internal loading lock
+        with lazy._lock:
+            lazy._flush_bg_loading_exception()
 
 
 def test_with_appcontext(runner):