Fixed #33185 -- Fixed sqlmigrate crash for RenameModel with a self-referential foreign key.

django/db/backends/base/schema.py

@@ -153,6 +153,9 @@ def __init__(self, connection, collect_sql=False, atomic=True):
         self.collect_sql = collect_sql
         if self.collect_sql:
             self.collected_sql = []
+            # Tables renamed while collecting SQL don't exist under their new
+            # name in the database, so introspection must target the old name.
+            self.collected_table_renames = {}
         self.atomic_migration = self.connection.features.can_rollback_ddl and atomic
 
     # State-managing methods
@@ -697,6 +700,14 @@ def alter_db_table(self, model, old_db_table, new_db_table):
                 "new_table": self.quote_name(new_db_table),
             }
         )
+        if self.collect_sql:
+            # The rename isn't executed, so later introspection of the new
+            # table name must be redirected to the still-existing old one,
+            # following any earlier rename of the same table in this batch.
+            existing_table = self.collected_table_renames.pop(
+                old_db_table, old_db_table
+            )
+            self.collected_table_renames[new_db_table] = existing_table
         # Rename all references to the old table name.
         for sql in self.deferred_sql:
             if isinstance(sql, Statement):
@@ -2019,9 +2030,12 @@ def _constraint_names(
                 )
                 for name in column_names
             ]
+        table_name = model._meta.db_table
+        if self.collect_sql:
+            table_name = self.collected_table_renames.get(table_name, table_name)
         with self.connection.cursor() as cursor:
             constraints = self.connection.introspection.get_constraints(
-                cursor, model._meta.db_table
+                cursor, table_name
             )
         result = []
         for name, infodict in constraints.items():

tests/migrations/test_operations.py

@@ -938,6 +938,30 @@ def test_rename_model_with_self_referential_fk(self):
                 "test_rmwsrf_rider", ["friend_id"], ("test_rmwsrf_horserider", "id")
             )
 
+    def test_rename_model_with_self_referential_fk_collect_sql(self):
+        """
+        Collecting SQL (e.g. sqlmigrate) for a RenameModel operation on a model
+        with a self-referential foreign key doesn't introspect the renamed
+        table, which doesn't exist yet (#33185).
+        """
+        project_state = self.set_up_test_model("test_rmwsrfcs", related_model=True)
+        operation = migrations.RenameModel("Rider", "HorseRider")
+        new_state = project_state.clone()
+        operation.state_forwards("test_rmwsrfcs", new_state)
+        with connection.schema_editor(collect_sql=True) as editor:
+            operation.database_forwards(
+                "test_rmwsrfcs", editor, project_state, new_state
+            )
+            collected_sql = "\n".join(editor.collected_sql)
+        # The table is renamed without crashing on introspection of the
+        # not-yet-renamed table, and the self-referential FK is handled
+        # (rather than silently skipped) using the constraint introspected
+        # from the still-existing old table.
+        self.assertIn(
+            connection.ops.quote_name("test_rmwsrfcs_horserider"), collected_sql
+        )
+        self.assertIn("friend_id", collected_sql)
+
     def test_rename_model_with_superclass_fk(self):
         """
         Tests the RenameModel operation on a model which has a superclass that