Fixed #33174 -- Fixed migrations crash for model inheriting from Generic[T].

6 files changed, 115 insertions, 0 deletions

diff --git a/tests/migrations/migrations_test_apps/with_generic_model/__init__.py b/tests/migrations/migrations_test_apps/with_generic_model/__init__.py
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/tests/migrations/migrations_test_apps/with_generic_model/__init__.py
diff --git a/tests/migrations/migrations_test_apps/with_generic_model/migrations/0001_initial.py b/tests/migrations/migrations_test_apps/with_generic_model/migrations/0001_initial.py
new file mode 100644
index 0000000000..efb998918a
--- /dev/null
+++ b/tests/migrations/migrations_test_apps/with_generic_model/migrations/0001_initial.py
@@ -0,0 +1,40 @@
+import typing
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+    initial = True
+
+    operations = [
+        migrations.CreateModel(
+            name="GenericModel",
+            fields=[
+                (
+                    "id",
+                    models.AutoField(
+                        auto_created=True,
+                        primary_key=True,
+                        serialize=False,
+                        verbose_name="ID",
+                    ),
+                ),
+            ],
+            bases=(typing.Generic, models.Model),
+        ),
+        migrations.CreateModel(
+            name="GenericModelPEP695",
+            fields=[
+                (
+                    "id",
+                    models.AutoField(
+                        auto_created=True,
+                        primary_key=True,
+                        serialize=False,
+                        verbose_name="ID",
+                    ),
+                ),
+            ],
+            bases=(models.Model, typing.Generic),
+        ),
+    ]
diff --git a/tests/migrations/migrations_test_apps/with_generic_model/migrations/0002_customgenericmodel.py b/tests/migrations/migrations_test_apps/with_generic_model/migrations/0002_customgenericmodel.py
new file mode 100644
index 0000000000..7d40eec5bf
--- /dev/null
+++ b/tests/migrations/migrations_test_apps/with_generic_model/migrations/0002_customgenericmodel.py
@@ -0,0 +1,31 @@
+from django.db import migrations, models
+
+from ..models import Child
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("with_generic_model", "0001_initial"),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name="CustomGenericModel",
+            fields=[
+                (
+                    "id",
+                    models.AutoField(
+                        auto_created=True,
+                        primary_key=True,
+                        serialize=False,
+                        verbose_name="ID",
+                    ),
+                ),
+            ],
+            bases=(
+                Child,
+                models.Model,
+            ),
+        ),
+    ]
diff --git a/tests/migrations/migrations_test_apps/with_generic_model/migrations/__init__.py b/tests/migrations/migrations_test_apps/with_generic_model/migrations/__init__.py
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/tests/migrations/migrations_test_apps/with_generic_model/migrations/__init__.py
diff --git a/tests/migrations/migrations_test_apps/with_generic_model/models.py b/tests/migrations/migrations_test_apps/with_generic_model/models.py
new file mode 100644
index 0000000000..2cedbe2f5b
--- /dev/null
+++ b/tests/migrations/migrations_test_apps/with_generic_model/models.py
@@ -0,0 +1,36 @@
+import typing
+
+from django.db import models
+
+T = typing.TypeVar("T")
+
+
+class GenericModel(typing.Generic[T], models.Model):
+    """A model inheriting from typing.Generic."""
+
+
+class GenericModelPEP695[T](models.Model):
+    """A model inheriting from typing.Generic via the PEP 695 syntax."""
+
+
+# Example from Python docs:
+# https://typing.python.org/en/latest/spec/generics.html#arbitrary-generic-types-as-base-classes
+T1 = typing.TypeVar("T1")
+T2 = typing.TypeVar("T2")
+T3 = typing.TypeVar("T3")
+
+
+class Parent1(typing.Generic[T1, T2]):
+    pass
+
+
+class Parent2(typing.Generic[T1, T2]):
+    pass
+
+
+class Child(Parent1[T1, T3], Parent2[T2, T3]):
+    pass
+
+
+class CustomGenericModel(Child[T1, T3, T2], models.Model):
+    """A model inheriting from a custom subclass of typing.Generic."""
diff --git a/tests/migrations/test_commands.py b/tests/migrations/test_commands.py
index 00f97c5f3a..f1373eca1e 100644
--- a/tests/migrations/test_commands.py
+++ b/tests/migrations/test_commands.py
@@ -1551,6 +1551,14 @@ class MigrateTests(MigrationTestBase):
             recorder.record_unapplied("migrations2", "0002_second")
             recorder.record_unapplied("migrations2", "0001_squashed_0002")
 
+    @override_settings(
+        INSTALLED_APPS=[
+            "migrations.migrations_test_apps.with_generic_model",
+        ]
+    )
+    def test_migrate_model_inherit_generic(self):
+        call_command("migrate", verbosity=0)
+
 
 class MakeMigrationsTests(MigrationTestBase):
     """