Merge pull request #2938 from dekkers/ticket_23071

Fixed #23071 -- Use last migration's name in dependency to other app

django/db/migrations/autodetector.py

@@ -254,13 +254,13 @@ class MigrationAutodetector(object):
                                     # If we can't find the other app, we add a first/last dependency,
                                     # but only if we've already been through once and checked everything
                                     if chop_mode:
-                                        # If the app already exists, we add __latest__, as we don't know which
-                                        # migration contains the target field.
+                                        # If the app already exists, we add a dependency on the last migration,
+                                        # as we don't know which migration contains the target field.
                                         # If it's not yet migrated or has no migrations, we use __first__
-                                        if graph and not graph.root_nodes(dep[0]):
-                                            operation_dependencies.add((dep[0], "__first__"))
+                                        if graph and graph.leaf_nodes(dep[0]):
+                                            operation_dependencies.add(graph.leaf_nodes(dep[0])[0])
                                         else:
-                                            operation_dependencies.add((dep[0], "__latest__"))
+                                            operation_dependencies.add((dep[0], "__first__"))
                                     else:
                                         deps_satisfied = False
                     if deps_satisfied:

django/db/migrations/loader.py

@@ -136,7 +136,7 @@ class MigrationLoader(object):
             return self.disk_migrations[results[0]]
 
     def check_key(self, key, current_app):
-        if (key[1] != "__first__" and key[1] != "__latest__") or key in self.graph:
+        if key[1] != "__first__" or key in self.graph:
             return key
         # Special-case __first__, which means "the first migration" for
         # migrated apps, and is ignored for unmigrated apps. It allows

tests/migrations/test_autodetector.py

@@ -1069,7 +1069,8 @@ class AutodetectorTests(TestCase):
     @override_settings(MIGRATION_MODULES={"migrations": "migrations.test_migrations"})
     def test_last_dependency(self):
         """
-        Tests that a dependency to an app with existing migrations uses __latest__.
+        Tests that a dependency to an app with existing migrations uses the
+        last migration of that app.
         """
         # Load graph
         loader = MigrationLoader(connection)
@@ -1084,4 +1085,4 @@ class AutodetectorTests(TestCase):
         self.assertOperationTypes(changes, 'otherapp', 0, ["CreateModel"])
         self.assertOperationAttributes(changes, 'otherapp', 0, 0, name="Book")
         # Right dependencies?
-        self.assertEqual(changes['otherapp'][0].dependencies, [("migrations", "__latest__")])
+        self.assertEqual(changes['otherapp'][0].dependencies, [("migrations", "0002_second")])

tests/migrations/test_loader.py

@@ -122,26 +122,6 @@ class LoaderTests(TestCase):
             ],
         )
 
-    @modify_settings(INSTALLED_APPS={'append': 'basic'})
-    @override_settings(MIGRATION_MODULES={
-        "migrations": "migrations.test_migrations_latest",
-        "basic": "migrations.test_migrations_latest_basic",
-    })
-    def test_latest(self):
-        """
-        Makes sure that __latest__ works correctly.
-        """
-        # Load and test the plan
-        migration_loader = MigrationLoader(connection)
-        self.assertEqual(
-            migration_loader.graph.forwards_plan(("migrations", "0001_initial")),
-            [
-                ("basic", "0001_initial"),
-                ("basic", "0002_second"),
-                ("migrations", "0001_initial"),
-            ],
-        )
-
     @override_settings(MIGRATION_MODULES={
         "migrations": "migrations.test_migrations_first",
         "migrations2": "migrations2.test_migrations_2_first",

tests/migrations/test_migrations_latest/0001_initial.py

@@ -1,13 +0,0 @@
-# -*- coding: utf-8 -*-
-from __future__ import unicode_literals
-
-from django.db import migrations
-
-
-class Migration(migrations.Migration):
-
-    dependencies = [
-        ("basic", "__latest__"),
-    ]
-
-    operations = []

tests/migrations/test_migrations_latest_basic/0001_initial.py

@@ -1,11 +0,0 @@
-# -*- coding: utf-8 -*-
-from __future__ import unicode_literals
-
-from django.db import migrations
-
-
-class Migration(migrations.Migration):
-
-    dependencies = []
-
-    operations = []

tests/migrations/test_migrations_latest_basic/0002_second.py

@@ -1,13 +0,0 @@
-# -*- coding: utf-8 -*-
-from __future__ import unicode_literals
-
-from django.db import migrations
-
-
-class Migration(migrations.Migration):
-
-    dependencies = [
-        ("basic", "0001_initial"),
-    ]
-
-    operations = []