[3.1.x] Fixed #32202 -- Fixed autoreloader argument generation for Windows with Python 3.7-.

Backport of ead37dfb58 from master

django/utils/autoreload.py

@@ -221,11 +221,15 @@ def get_child_arguments():
         exe_entrypoint = py_script.with_suffix('.exe')
         if exe_entrypoint.exists():
             # Should be executed directly, ignoring sys.executable.
-            return [exe_entrypoint, *sys.argv[1:]]
+            # TODO: Remove str() when dropping support for PY37.
+            # args parameter accepts path-like on Windows from Python 3.8.
+            return [str(exe_entrypoint), *sys.argv[1:]]
         script_entrypoint = py_script.with_name('%s-script.py' % py_script.name)
         if script_entrypoint.exists():
             # Should be executed as usual.
-            return [*args, script_entrypoint, *sys.argv[1:]]
+            # TODO: Remove str() when dropping support for PY37.
+            # args parameter accepts path-like on Windows from Python 3.8.
+            return [*args, str(script_entrypoint), *sys.argv[1:]]
         raise RuntimeError('Script %s does not exist.' % py_script)
     else:
         args += sys.argv

docs/releases/3.1.4.txt

@@ -17,3 +17,7 @@ Bugfixes
 
 * Fixed crash of key transforms for :class:`~django.db.models.JSONField` on
   PostgreSQL when using on a ``Subquery()`` annotation (:ticket:`32182`).
+
+* Fixed a regression in Django 3.1 that caused a crash of auto-reloader for
+  certain invocations of ``runserver`` on Windows with Python 3.7 and below
+  (:ticket:`32202`).

tests/utils_tests/test_autoreload.py

@@ -177,10 +177,10 @@ class TestChildArguments(SimpleTestCase):
         self.addCleanup(tmpdir.cleanup)
         exe_path = Path(tmpdir.name) / 'django-admin.exe'
         exe_path.touch()
-        with mock.patch('sys.argv', [exe_path.with_suffix(''), 'runserver']):
+        with mock.patch('sys.argv', [str(exe_path.with_suffix('')), 'runserver']):
             self.assertEqual(
                 autoreload.get_child_arguments(),
-                [exe_path, 'runserver']
+                [str(exe_path), 'runserver']
             )
 
     @mock.patch('sys.warnoptions', [])
@@ -189,10 +189,10 @@ class TestChildArguments(SimpleTestCase):
         self.addCleanup(tmpdir.cleanup)
         script_path = Path(tmpdir.name) / 'django-admin-script.py'
         script_path.touch()
-        with mock.patch('sys.argv', [script_path.with_name('django-admin'), 'runserver']):
+        with mock.patch('sys.argv', [str(script_path.with_name('django-admin')), 'runserver']):
             self.assertEqual(
                 autoreload.get_child_arguments(),
-                [sys.executable, script_path, 'runserver']
+                [sys.executable, str(script_path), 'runserver']
             )
 
     @mock.patch('sys.argv', ['does-not-exist', 'runserver'])
@@ -413,7 +413,7 @@ class RestartWithReloaderTests(SimpleTestCase):
         with tempfile.TemporaryDirectory() as temp_dir:
             script = Path(temp_dir) / 'manage.py'
             script.touch()
-            argv = [script, 'runserver']
+            argv = [str(script), 'runserver']
             mock_call = self.patch_autoreload(argv)
             autoreload.restart_with_reloader()
             self.assertEqual(mock_call.call_count, 1)