Add --debug option to flask run

CHANGES.rst

@@ -7,6 +7,7 @@ Unreleased
     templates this behavior can be changed with the ``autoescape`` tag.
     :issue:`4831`
 -   Fix the type of ``template_folder`` to accept ``pathlib.Path``. :issue:`4892`
+-   Add ``--debug`` option to the ``flask run`` command. :issue:`4777`
 
 
 Version 2.2.2

src/flask/cli.py

@@ -837,6 +837,11 @@ class SeparatedPathType(click.Path):
     expose_value=False,
     help="The key file to use when specifying a certificate.",
 )
+@click.option(
+    "--debug/--no-debug",
+    default=None,
+    help="Enable or disable the debug mode.",
+)
 @click.option(
     "--reload/--no-reload",
     default=None,
@@ -878,6 +883,7 @@ def run_command(
     info,
     host,
     port,
+    debug,
     reload,
     debugger,
     with_threads,
@@ -910,7 +916,8 @@ def run_command(
             # command fails.
             raise e from None
 
-    debug = get_debug_flag()
+    if debug is None:
+        debug = get_debug_flag()
 
     if reload is None:
         reload = debug