Fixed #34051 -- Made makemigrations --check exit before making migrations.

django/core/management/commands/makemigrations.py

@@ -70,7 +70,10 @@ class Command(BaseCommand):
             "--check",
             action="store_true",
             dest="check_changes",
-            help="Exit with a non-zero status if model changes are missing migrations.",
+            help=(
+                "Exit with a non-zero status if model changes are missing migrations "
+                "and don't actually write them."
+            ),
         )
         parser.add_argument(
             "--scriptable",
@@ -248,12 +251,12 @@ class Command(BaseCommand):
                 else:
                     self.log("No changes detected")
         else:
+            if check_changes:
+                sys.exit(1)
             if self.update:
                 self.write_to_last_migration_files(changes)
             else:
                 self.write_migration_files(changes)
-            if check_changes:
-                sys.exit(1)
 
     def write_to_last_migration_files(self, changes):
         loader = MigrationLoader(connections[DEFAULT_DB_ALIAS])

docs/ref/django-admin.txt

@@ -825,6 +825,11 @@ Generate migration files without Django version and timestamp header.
 Makes ``makemigrations`` exit with a non-zero status when model changes without
 migrations are detected.
 
+.. versionchanged:: 4.2
+
+    In older versions, the missing migrations were also created when using the
+    ``--check`` option.
+
 .. django-admin-option:: --scriptable
 
 .. versionadded:: 4.1

docs/releases/4.2.txt

@@ -322,6 +322,9 @@ Miscellaneous
 * The ``autofocus`` HTML attribute in the admin search box is removed as it can
   be confusing for screen readers.
 
+* The :option:`makemigrations --check` option no longer creates missing
+  migration files.
+
 .. _deprecated-features-4.2:
 
 Features deprecated in 4.2

tests/migrations/test_commands.py

@@ -2391,9 +2391,10 @@ class MakeMigrationsTests(MigrationTestBase):
         makemigrations --check should exit with a non-zero status when
         there are changes to an app requiring migrations.
         """
-        with self.temporary_migration_module():
+        with self.temporary_migration_module() as tmpdir:
             with self.assertRaises(SystemExit):
                 call_command("makemigrations", "--check", "migrations", verbosity=0)
+            self.assertFalse(os.path.exists(tmpdir))
 
         with self.temporary_migration_module(
             module="migrations.test_migrations_no_changes"