[1.7.x] Fixed #23699 -- Prevented flush from loading initial data for apps with migrations.

Backport of dd1ea707 from master.

django/core/management/commands/flush.py

@@ -84,9 +84,13 @@ Are you sure you want to do this?
 
             # Reinstall the initial_data fixture.
             if options.get('load_initial_data'):
-                # Reinstall the initial_data fixture.
-                call_command('loaddata', 'initial_data', **options)
-
+                # Reinstall the initial_data fixture for apps without migrations.
+                from django.db.migrations.executor import MigrationExecutor
+                executor = MigrationExecutor(connection)
+                app_options = options.copy()
+                for app_label in executor.loader.unmigrated_apps:
+                    app_options['app_label'] = app_label
+                    call_command('loaddata', 'initial_data', **app_options)
         else:
             self.stdout.write("Flush cancelled.\n")
 

docs/releases/1.7.2.txt

@@ -18,3 +18,6 @@ Bugfixes
 * Warn for duplicate models when a module is reloaded. Previously a
 RuntimeError was raised every time two models clashed in the app registry.
 (:ticket:`23621`).
+
+* Prevented :djadmin:`flush` from loading initial data for migrated apps
+  (:ticket:`23699`).

tests/fixtures_migration/fixtures/initial_data.json

+[
+    {
+        "pk": "10",
+        "model": "fixtures_migration.book",
+        "fields": {
+            "name": "Achieving self-awareness of Python programs"
+        }
+    }
+]

tests/fixtures_migration/migrations/0001_initial.py

+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    operations = [
+        migrations.CreateModel(
+            "Book",
+            [
+                ("name", models.CharField(max_length=100)),
+            ],
+        ),
+    ]

tests/fixtures_migration/models.py

+from django.db import models
+
+
+class Book(models.Model):
+    name = models.CharField(max_length=100)

tests/fixtures_migration/tests.py

+from django.test import TestCase
+from django.core import management
+
+from .models import Book
+
+
+class TestNoInitialDataLoading(TestCase):
+    """
+    Apps with migrations should ignore initial data. This test can be removed
+    in Django 1.9 when migrations become required and initial data is no longer
+    supported.
+    """
+    available_apps = ['django.contrib.auth', 'django.contrib.contenttypes', 'fixtures_migration']
+
+    def test_migrate(self):
+        self.assertQuerysetEqual(Book.objects.all(), [])
+        management.call_command(
+            'migrate',
+            verbosity=0,
+        )
+        self.assertQuerysetEqual(Book.objects.all(), [])
+
+    def test_flush(self):
+        self.assertQuerysetEqual(Book.objects.all(), [])
+        management.call_command(
+            'flush',
+            verbosity=0,
+            interactive=False,
+            load_initial_data=False
+        )
+        self.assertQuerysetEqual(Book.objects.all(), [])