[3.0.x] Fixed #30868 -- Prevented unnecessary AlterField when renaming a referenced pk.

Regression introduced by dcdd219ee1, refs #25817.

Thanks Carlos E. C. Leite for the report and Mariusz for the bisect.

Backport of 2839659b42 from master

django/db/migrations/autodetector.py

@@ -927,6 +927,10 @@ class MigrationAutodetector:
                 if remote_field_name:
                     to_field_rename_key = rename_key + (remote_field_name,)
                     if to_field_rename_key in self.renamed_fields:
+                        # Repoint both model and field name because to_field
+                        # inclusion in ForeignKey.deconstruct() is based on
+                        # both.
+                        new_field.remote_field.model = old_field.remote_field.model
                         new_field.remote_field.field_name = old_field.remote_field.field_name
                 # Handle ForeignObjects which can have multiple from_fields/to_fields.
                 from_fields = getattr(new_field, 'from_fields', None)

tests/migrations/test_autodetector.py

@@ -932,6 +932,30 @@ class AutodetectorTests(TestCase):
             changes, 'app', 0, 1, model_name='bar', old_name='second', new_name='second_renamed',
         )
 
+    def test_rename_referenced_primary_key(self):
+        before = [
+            ModelState('app', 'Foo', [
+                ('id', models.CharField(primary_key=True, serialize=False)),
+            ]),
+            ModelState('app', 'Bar', [
+                ('id', models.AutoField(primary_key=True)),
+                ('foo', models.ForeignKey('app.Foo', models.CASCADE)),
+            ]),
+        ]
+        after = [
+            ModelState('app', 'Foo', [
+                ('renamed_id', models.CharField(primary_key=True, serialize=False))
+            ]),
+            ModelState('app', 'Bar', [
+                ('id', models.AutoField(primary_key=True)),
+                ('foo', models.ForeignKey('app.Foo', models.CASCADE)),
+            ]),
+        ]
+        changes = self.get_changes(before, after, MigrationQuestioner({'ask_rename': True}))
+        self.assertNumberMigrations(changes, 'app', 1)
+        self.assertOperationTypes(changes, 'app', 0, ['RenameField'])
+        self.assertOperationAttributes(changes, 'app', 0, 0, old_name='id', new_name='renamed_id')
+
     def test_rename_field_preserved_db_column(self):
         """
         RenameField is used if a field is renamed and db_column equal to the