Fixed #22783: Make sure swappable models come first in creation

2 files changed, 58 insertions, 2 deletions

diff --git a/django/db/migrations/autodetector.py b/django/db/migrations/autodetector.py
index 3b9caee8fc..acdfa2a668 100644
--- a/django/db/migrations/autodetector.py
+++ b/django/db/migrations/autodetector.py
@@ -5,6 +5,7 @@ import datetime
 
 from django.utils import six
 from django.db import models
+from django.conf import settings
 from django.db.migrations import operations
 from django.db.migrations.migration import Migration
 from django.db.migrations.questioner import MigrationQuestioner
@@ -345,6 +346,27 @@ class MigrationAutodetector(object):
         operation._auto_deps = dependencies or []
         self.generated_operations.setdefault(app_label, []).append(operation)
 
+    def swappable_first_key(self, item):
+        """
+        Sorting key function that places potential swappable models first in
+        lists of created models (only real way to solve #22783)
+        """
+        try:
+            model = self.new_apps.get_model(item[0], item[1])
+            base_names = [base.__name__ for base in model.__bases__]
+            string_version = "%s.%s" % (item[0], item[1])
+            if (
+                model._meta.swappable or
+                "AbstractUser" in base_names or
+                "AbstractBaseUser" in base_names or
+                settings.AUTH_USER_MODEL.lower() == string_version.lower()
+            ):
+                return ("___" + item[0], "___" + item[1])
+        except LookupError:
+            pass
+        return item
+
+
     def generate_renamed_models(self):
         """
         Finds any renamed models, and generates the operations for them,
@@ -388,7 +410,7 @@ class MigrationAutodetector(object):
         that might be deferred (e.g. unique_together, index_together)
         """
         added_models = set(self.new_model_keys) - set(self.old_model_keys)
-        for app_label, model_name in sorted(added_models):
+        for app_label, model_name in sorted(added_models, key=self.swappable_first_key):
             model_state = self.to_state.models[app_label, model_name]
             # Gather related fields
             related_fields = {}
diff --git a/tests/migrations/test_autodetector.py b/tests/migrations/test_autodetector.py
index b1233dc41f..b09402bd82 100644
--- a/tests/migrations/test_autodetector.py
+++ b/tests/migrations/test_autodetector.py
@@ -5,6 +5,7 @@ from django.db.migrations.questioner import MigrationQuestioner
 from django.db.migrations.state import ProjectState, ModelState
 from django.db.migrations.graph import MigrationGraph
 from django.db import models
+from django.contrib.auth.models import AbstractBaseUser
 
 
 class DeconstructableObject(object):
@@ -67,7 +68,9 @@ class AutodetectorTests(TestCase):
     book_unique_3 = ModelState("otherapp", "Book", [("id", models.AutoField(primary_key=True)), ("newfield", models.IntegerField()), ("author", models.ForeignKey("testapp.Author")), ("title", models.CharField(max_length=200))], {"unique_together": [("title", "newfield")]})
     attribution = ModelState("otherapp", "Attribution", [("id", models.AutoField(primary_key=True)), ("author", models.ForeignKey("testapp.Author")), ("book", models.ForeignKey("otherapp.Book"))])
     edition = ModelState("thirdapp", "Edition", [("id", models.AutoField(primary_key=True)), ("book", models.ForeignKey("otherapp.Book"))])
-    custom_user = ModelState("thirdapp", "CustomUser", [("id", models.AutoField(primary_key=True)), ("username", models.CharField(max_length=255))])
+    custom_user = ModelState("thirdapp", "CustomUser", [("id", models.AutoField(primary_key=True)), ("username", models.CharField(max_length=255))], bases=(AbstractBaseUser, ))
+    custom_user_no_inherit = ModelState("thirdapp", "CustomUser", [("id", models.AutoField(primary_key=True)), ("username", models.CharField(max_length=255))])
+    aardvark = ModelState("thirdapp", "Aardvark", [("id", models.AutoField(primary_key=True))])
     knight = ModelState("eggs", "Knight", [("id", models.AutoField(primary_key=True))])
     rabbit = ModelState("eggs", "Rabbit", [("id", models.AutoField(primary_key=True)), ("knight", models.ForeignKey("eggs.Knight")), ("parent", models.ForeignKey("eggs.Rabbit"))], {"unique_together": [("parent", "knight")]})
 
@@ -913,3 +916,34 @@ class AutodetectorTests(TestCase):
         self.assertOperationAttributes(changes, 'testapp', 0, 1, name="author", order_with_respect_to="book")
         # Make sure the _order field is not in the CreateModel fields
         self.assertNotIn("_order", [name for name, field in changes['testapp'][0].operations[0].fields])
+
+    def test_swappable_first_inheritance(self):
+        """
+        Tests that swappable models get their CreateModel first.
+        """
+        # Make state
+        before = self.make_project_state([])
+        after = self.make_project_state([self.custom_user, self.aardvark])
+        autodetector = MigrationAutodetector(before, after)
+        changes = autodetector._detect_changes()
+        # Right number of migrations?
+        self.assertNumberMigrations(changes, 'thirdapp', 1)
+        self.assertOperationTypes(changes, 'thirdapp', 0, ["CreateModel", "CreateModel"])
+        self.assertOperationAttributes(changes, 'thirdapp', 0, 0, name="CustomUser")
+        self.assertOperationAttributes(changes, 'thirdapp', 0, 1, name="Aardvark")
+
+    @override_settings(AUTH_USER_MODEL="thirdapp.CustomUser")
+    def test_swappable_first_setting(self):
+        """
+        Tests that swappable models get their CreateModel first.
+        """
+        # Make state
+        before = self.make_project_state([])
+        after = self.make_project_state([self.custom_user_no_inherit, self.aardvark])
+        autodetector = MigrationAutodetector(before, after)
+        changes = autodetector._detect_changes()
+        # Right number of migrations?
+        self.assertNumberMigrations(changes, 'thirdapp', 1)
+        self.assertOperationTypes(changes, 'thirdapp', 0, ["CreateModel", "CreateModel"])
+        self.assertOperationAttributes(changes, 'thirdapp', 0, 0, name="CustomUser")
+        self.assertOperationAttributes(changes, 'thirdapp', 0, 1, name="Aardvark")