[1.7.x] Fixed #23322 -- Use resolved swappable model for dependency resolution during makemigrations

Backport of 144cff3f51 from master

2 files changed, 95 insertions, 3 deletions

diff --git a/django/db/migrations/autodetector.py b/django/db/migrations/autodetector.py
index e67c8aa902..4a837fbba1 100644
--- a/django/db/migrations/autodetector.py
+++ b/django/db/migrations/autodetector.py
@@ -237,9 +237,17 @@ class MigrationAutodetector(object):
                     deps_satisfied = True
                     operation_dependencies = set()
                     for dep in operation._auto_deps:
+                        is_swappable_dep = False
                         if dep[0] == "__setting__":
-                            operation_dependencies.add((dep[0], dep[1]))
-                        elif dep[0] != app_label:
+                            # We need to temporarily resolve the swappable dependency to prevent
+                            # circular references. While keeping the dependency checks on the
+                            # resolved model we still add the swappable dependencies.
+                            # See #23322
+                            resolved_app_label, resolved_object_name = getattr(settings, dep[1]).split('.')
+                            original_dep = dep
+                            dep = (resolved_app_label, resolved_object_name.lower(), dep[2], dep[3])
+                            is_swappable_dep = True
+                        if dep[0] != app_label and dep[0] != "__setting__":
                             # External app dependency. See if it's not yet
                             # satisfied.
                             for other_operation in self.generated_operations.get(dep[0], []):
@@ -249,7 +257,9 @@ class MigrationAutodetector(object):
                             if not deps_satisfied:
                                 break
                             else:
-                                if self.migrations.get(dep[0], None):
+                                if is_swappable_dep:
+                                    operation_dependencies.add((original_dep[0], original_dep[1]))
+                                elif dep[0] in self.migrations:
                                     operation_dependencies.add((dep[0], self.migrations[dep[0]][-1].name))
                                 else:
                                     # If we can't find the other app, we add a first/last dependency,
diff --git a/tests/migrations/test_autodetector.py b/tests/migrations/test_autodetector.py
index 31551f5368..3cfba95e00 100644
--- a/tests/migrations/test_autodetector.py
+++ b/tests/migrations/test_autodetector.py
@@ -1,4 +1,5 @@
 # -*- coding: utf-8 -*-
+from django.conf import settings
 from django.test import TestCase, override_settings
 from django.db.migrations.autodetector import MigrationAutodetector
 from django.db.migrations.questioner import MigrationQuestioner
@@ -1091,3 +1092,84 @@ class AutodetectorTests(TestCase):
         self.assertOperationTypes(changes, 'a', 0, ["CreateModel", "CreateModel"])
         self.assertOperationTypes(changes, 'a', 1, ["AddField"])
         self.assertOperationTypes(changes, 'b', 0, ["CreateModel", "CreateModel"])
+
+    @override_settings(AUTH_USER_MODEL="a.Tenant")
+    def test_circular_dependency_swappable(self):
+        """
+        Tests that the dependency resolver knows to explicitly resolve
+        swappable models (#23322)
+        """
+        tenant = ModelState("a", "Tenant", [
+            ("id", models.AutoField(primary_key=True)),
+            ("primary_address", models.ForeignKey("b.Address"))],
+            bases=(AbstractBaseUser, )
+        )
+        address = ModelState("b", "Address", [
+            ("id", models.AutoField(primary_key=True)),
+            ("tenant", models.ForeignKey(settings.AUTH_USER_MODEL)),
+        ])
+        # Make state
+        before = self.make_project_state([])
+        after = self.make_project_state([address, tenant])
+        autodetector = MigrationAutodetector(before, after)
+        changes = autodetector._detect_changes()
+        # Right number of migrations?
+        self.assertNumberMigrations(changes, 'a', 2)
+        self.assertNumberMigrations(changes, 'b', 1)
+        self.assertOperationTypes(changes, 'a', 0, ["CreateModel"])
+        self.assertOperationTypes(changes, 'a', 1, ["AddField"])
+        self.assertOperationTypes(changes, 'b', 0, ["CreateModel"])
+        self.assertEqual(changes['a'][0].dependencies, [])
+        self.assertEqual(set(changes['a'][1].dependencies), set([('a', 'auto_1'), ('b', 'auto_1')]))
+        self.assertEqual(changes['b'][0].dependencies, [('__setting__', 'AUTH_USER_MODEL')])
+
+    @override_settings(AUTH_USER_MODEL="b.Tenant")
+    def test_circular_dependency_swappable2(self):
+        """
+        Tests that the dependency resolver knows to explicitly resolve
+        swappable models but with the swappable not being the first migrated
+        model (#23322)
+        """
+        address = ModelState("a", "Address", [
+            ("id", models.AutoField(primary_key=True)),
+            ("tenant", models.ForeignKey(settings.AUTH_USER_MODEL)),
+        ])
+        tenant = ModelState("b", "Tenant", [
+            ("id", models.AutoField(primary_key=True)),
+            ("primary_address", models.ForeignKey("a.Address"))],
+            bases=(AbstractBaseUser, )
+        )
+        # Make state
+        before = self.make_project_state([])
+        after = self.make_project_state([address, tenant])
+        autodetector = MigrationAutodetector(before, after)
+        changes = autodetector._detect_changes()
+        # Right number of migrations?
+        self.assertNumberMigrations(changes, 'a', 2)
+        self.assertNumberMigrations(changes, 'b', 1)
+        self.assertOperationTypes(changes, 'a', 0, ["CreateModel"])
+        self.assertOperationTypes(changes, 'a', 1, ["AddField"])
+        self.assertOperationTypes(changes, 'b', 0, ["CreateModel"])
+        self.assertEqual(changes['a'][0].dependencies, [])
+        self.assertEqual(set(changes['a'][1].dependencies), set([('__setting__', 'AUTH_USER_MODEL'), ('a', 'auto_1')]))
+        self.assertEqual(changes['b'][0].dependencies, [('a', 'auto_1')])
+
+    @override_settings(AUTH_USER_MODEL="a.Person")
+    def test_circular_dependency_swappable_self(self):
+        """
+        Tests that the dependency resolver knows to explicitly resolve
+        swappable models (#23322)
+        """
+        person = ModelState("a", "Person", [
+            ("id", models.AutoField(primary_key=True)),
+            ("parent1", models.ForeignKey(settings.AUTH_USER_MODEL, related_name='children'))
+        ])
+        # Make state
+        before = self.make_project_state([])
+        after = self.make_project_state([person])
+        autodetector = MigrationAutodetector(before, after)
+        changes = autodetector._detect_changes()
+        # Right number of migrations?
+        self.assertNumberMigrations(changes, 'a', 1)
+        self.assertOperationTypes(changes, 'a', 0, ["CreateModel"])
+        self.assertEqual(changes['a'][0].dependencies, [])