[1.8.x] Revert "Fixed #24075 -- Prevented running post_migrate signals when unapplying initial migrations of contenttypes and auth"

This reverts commit 737d24923ac69bb8b89af1bb2f3f4c4c744349e8.

Backport of 2832a9b028c267997b2fd3dd0989670d57cdd08f from master

6 files changed, 9 insertions, 62 deletions

diff --git a/django/contrib/auth/management/__init__.py b/django/contrib/auth/management/__init__.py
index 9739005875..44d8563c14 100644
--- a/django/contrib/auth/management/__init__.py
+++ b/django/contrib/auth/management/__init__.py
@@ -11,7 +11,6 @@ from django.contrib.auth import get_permission_codename
 from django.core import exceptions
 from django.core.management.base import CommandError
 from django.db import DEFAULT_DB_ALIAS, router
-from django.db.migrations.loader import is_latest_migration_applied
 from django.utils.encoding import DEFAULT_LOCALE_ENCODING
 from django.utils import six
 
@@ -59,10 +58,6 @@ def _check_permission_clashing(custom, builtin, ctype):
 
 
 def create_permissions(app_config, verbosity=2, interactive=True, using=DEFAULT_DB_ALIAS, **kwargs):
-    # TODO: Remove when migration plan / state is passed (#24100).
-    if not is_latest_migration_applied('auth'):
-        return
-
     if not app_config.models_module:
         return
 
diff --git a/django/contrib/auth/tests/test_management.py b/django/contrib/auth/tests/test_management.py
index 36b81a8ceb..3d2aaceee9 100644
--- a/django/contrib/auth/tests/test_management.py
+++ b/django/contrib/auth/tests/test_management.py
@@ -17,7 +17,7 @@ from django.core import checks
 from django.core import exceptions
 from django.core.management import call_command
 from django.core.management.base import CommandError
-from django.test import TestCase, override_settings, override_system_checks, skipUnlessDBFeature
+from django.test import TestCase, override_settings, override_system_checks
 from django.utils import six
 from django.utils.encoding import force_str
 
@@ -570,21 +570,3 @@ class PermissionTestCase(TestCase):
         six.assertRaisesRegex(self, exceptions.ValidationError,
             "The verbose_name of auth.permission is longer than 244 characters",
             create_permissions, auth_app_config, verbosity=0)
-
-
-class MigrateTests(TestCase):
-
-    @skipUnlessDBFeature('can_rollback_ddl')
-    def test_unmigrating_first_migration_post_migrate_signal(self):
-        """
-        #24075 - When unmigrating an app before its first migration,
-        post_migrate signal handler must be aware of the missing tables.
-        """
-        try:
-            with override_settings(
-                INSTALLED_APPS=["django.contrib.auth", "django.contrib.contenttypes"],
-                MIGRATION_MODULES={'auth': 'django.contrib.auth.migrations'},
-            ):
-                call_command("migrate", "auth", "zero", stdout=six.StringIO())
-        finally:
-            call_command("migrate", stdout=six.StringIO())
diff --git a/django/contrib/contenttypes/management.py b/django/contrib/contenttypes/management.py
index 7dad8f1fe1..6364c752d2 100644
--- a/django/contrib/contenttypes/management.py
+++ b/django/contrib/contenttypes/management.py
@@ -1,6 +1,5 @@
 from django.apps import apps
 from django.db import DEFAULT_DB_ALIAS, router
-from django.db.migrations.loader import is_latest_migration_applied
 from django.utils import six
 from django.utils.six.moves import input
 
@@ -10,10 +9,6 @@ def update_contenttypes(app_config, verbosity=2, interactive=True, using=DEFAULT
     Creates content types for models in the given app, removing any model
     entries that no longer have a matching model class.
     """
-    # TODO: Remove when migration plan / state is passed (#24100).
-    if not is_latest_migration_applied('contenttypes'):
-        return
-
     if not app_config.models_module:
         return
 
diff --git a/django/contrib/contenttypes/tests/tests.py b/django/contrib/contenttypes/tests/tests.py
index ba0c339007..5ce9b395f1 100644
--- a/django/contrib/contenttypes/tests/tests.py
+++ b/django/contrib/contenttypes/tests/tests.py
@@ -5,9 +5,8 @@ import warnings
 from django.contrib.contenttypes.models import ContentType
 from django.contrib.contenttypes.views import shortcut
 from django.contrib.sites.shortcuts import get_current_site
-from django.core.management import call_command
-from django.http import HttpRequest, Http404
-from django.test import TestCase, override_settings, skipUnlessDBFeature
+from django.http import Http404, HttpRequest
+from django.test import TestCase, override_settings
 from django.utils import six
 
 from .models import ConcreteModel, ProxyModel, FooWithoutUrl, FooWithUrl, FooWithBrokenAbsoluteUrl
@@ -244,21 +243,6 @@ class ContentTypesTests(TestCase):
         ct_fetched = ContentType.objects.get_for_id(ct.pk)
         self.assertIsNone(ct_fetched.model_class())
 
-    @skipUnlessDBFeature('can_rollback_ddl')
-    def test_unmigrating_first_migration_post_migrate_signal(self):
-        """
-        #24075 - When unmigrating an app before its first migration,
-        post_migrate signal handler must be aware of the missing tables.
-        """
-        try:
-            with override_settings(
-                INSTALLED_APPS=["django.contrib.contenttypes"],
-                MIGRATION_MODULES={'contenttypes': 'django.contrib.contenttypes.migrations'},
-            ):
-                call_command("migrate", "contenttypes", "zero", stdout=six.StringIO())
-        finally:
-            call_command("migrate", stdout=six.StringIO())
-
     def test_name_deprecation(self):
         """
         ContentType.name has been removed. Test that a warning is emitted when
diff --git a/django/db/migrations/loader.py b/django/db/migrations/loader.py
index d7ee805bb1..ce6849f280 100644
--- a/django/db/migrations/loader.py
+++ b/django/db/migrations/loader.py
@@ -5,11 +5,10 @@ import os
 import sys
 
 from django.apps import apps
-from django.db import connection
-from django.db.migrations.recorder import MigrationRecorder
+from django.conf import settings
 from django.db.migrations.graph import MigrationGraph, NodeNotFoundError
+from django.db.migrations.recorder import MigrationRecorder
 from django.utils import six
-from django.conf import settings
 
 
 MIGRATIONS_MODULE_NAME = 'migrations'
@@ -340,14 +339,3 @@ class AmbiguityError(Exception):
     Raised when more than one migration matches a name prefix
     """
     pass
-
-
-def is_latest_migration_applied(app_label):
-    # TODO: Remove when migration plan / state is passed (#24100).
-    loader = MigrationLoader(connection)
-    loader.load_disk()
-    leaf_nodes = loader.graph.leaf_nodes(app=app_label)
-    return (
-        leaf_nodes and leaf_nodes[0] in loader.applied_migrations or
-        app_label in loader.unmigrated_apps
-    )
diff --git a/docs/releases/1.7.5.txt b/docs/releases/1.7.5.txt
index ba81a64b9a..2039c9dc4e 100644
--- a/docs/releases/1.7.5.txt
+++ b/docs/releases/1.7.5.txt
@@ -9,4 +9,7 @@ Django 1.7.5 fixes several bugs in 1.7.4.
 Bugfixes
 ========
 
-* ...
+* Reverted a fix that prevented a migration crash when unapplying
+  ``contrib.contenttypes``’s or ``contrib.auth``’s first migration
+  (:ticket:`24075`) due to severe impact on the test performance
+  (:ticket:`24251`) and problems in multi-database setups (:ticket:`24298`).