[2.2.x] Fixed #30479 -- Fixed detecting changes in manage.py by autoreloader when using StatReloader.

Regression in c8720e7696ca41f3262d5369365cc1bd72a216ca.

Backport of b2790f74d4f38c8b297b7c1cef6875d2378f6fa6 from master

3 files changed, 16 insertions, 1 deletions

diff --git a/django/utils/autoreload.py b/django/utils/autoreload.py
index de889c99bb..ade9abdfdf 100644
--- a/django/utils/autoreload.py
+++ b/django/utils/autoreload.py
@@ -111,7 +111,15 @@ def iter_modules_and_files(modules, extra_files):
         # During debugging (with PyDev) the 'typing.io' and 'typing.re' objects
         # are added to sys.modules, however they are types not modules and so
         # cause issues here.
-        if not isinstance(module, ModuleType) or getattr(module, '__spec__', None) is None:
+        if not isinstance(module, ModuleType):
+            continue
+        if module.__name__ == '__main__':
+            # __main__ (usually manage.py) doesn't always have a __spec__ set.
+            # Handle this by falling back to using __file__, resolved below.
+            # See https://docs.python.org/reference/import.html#main-spec
+            sys_file_paths.append(module.__file__)
+            continue
+        if getattr(module, '__spec__', None) is None:
             continue
         spec = module.__spec__
         # Modules could be loaded from places without a concrete location. If
diff --git a/docs/releases/2.2.2.txt b/docs/releases/2.2.2.txt
index d68338dce2..fc47100844 100644
--- a/docs/releases/2.2.2.txt
+++ b/docs/releases/2.2.2.txt
@@ -18,3 +18,6 @@ Bugfixes
 * Fixed a regression in Django 2.2.1 where
   :class:`~django.contrib.postgres.search.SearchVector` generates SQL with a
   redundant ``Coalesce`` call (:ticket:`30488`).
+
+* Fixed a regression in Django 2.2 where auto-reloader doesn't detect changes
+  in ``manage.py`` file when using ``StatReloader`` (:ticket:`30479`).
diff --git a/tests/utils_tests/test_autoreload.py b/tests/utils_tests/test_autoreload.py
index f0e692d274..9253482e7b 100644
--- a/tests/utils_tests/test_autoreload.py
+++ b/tests/utils_tests/test_autoreload.py
@@ -130,6 +130,10 @@ class TestIterModulesAndFiles(SimpleTestCase):
         del module.__spec__
         self.assertEqual(autoreload.iter_modules_and_files((module,), frozenset()), frozenset())
 
+    def test_main_module_is_resolved(self):
+        main_module = sys.modules['__main__']
+        self.assertFileFound(Path(main_module.__file__))
+
 
 class TestCommonRoots(SimpleTestCase):
     def test_common_roots(self):