Fixed #25855 -- Enhanced the migration warning for runserver.

Added unapplied migration count and the list of unmigrated apps.

django/core/management/commands/runserver.py

@@ -172,9 +172,17 @@ class Command(BaseCommand):
 
         plan = executor.migration_plan(executor.loader.graph.leaf_nodes())
         if plan:
-            self.stdout.write(self.style.NOTICE(
-                "\nYou have unapplied migrations; your app may not work properly until they are applied."
-            ))
+            apps_waiting_migration = sorted(set(migration.app_label for migration, backwards in plan))
+            self.stdout.write(
+                self.style.NOTICE(
+                    "\nYou have %(unpplied_migration_count)s unapplied migration(s). "
+                    "Your project may not work properly until you apply the "
+                    "migrations for app(s): %(apps_waiting_migration)s." % {
+                        "unpplied_migration_count": len(plan),
+                        "apps_waiting_migration": ", ".join(apps_waiting_migration),
+                    }
+                )
+            )
             self.stdout.write(self.style.NOTICE("Run 'python manage.py migrate' to apply them.\n"))
 
 # Kept for backward compatibility

tests/admin_scripts/another_app_waiting_migration/migrations/0001_initial.py

@@ -0,0 +1,21 @@
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    initial = True
+
+    dependencies = [
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='Foo',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('name', models.CharField(max_length=255)),
+            ],
+        ),
+    ]

tests/admin_scripts/another_app_waiting_migration/models.py

@@ -0,0 +1,10 @@
+from __future__ import unicode_literals
+
+from django.db import models
+
+
+class Foo(models.Model):
+    name = models.CharField(max_length=255)
+
+    class Meta:
+        app_label = 'another_app_waiting_migration'

tests/admin_scripts/app_waiting_migration/migrations/0001_initial.py

@@ -0,0 +1,21 @@
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    initial = True
+
+    dependencies = [
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='Bar',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('name', models.CharField(max_length=255)),
+            ],
+        ),
+    ]

tests/admin_scripts/app_waiting_migration/models.py

@@ -0,0 +1,10 @@
+from __future__ import unicode_literals
+
+from django.db import models
+
+
+class Bar(models.Model):
+    name = models.CharField(max_length=255)
+
+    class Meta:
+        app_label = 'app_waiting_migration'

tests/admin_scripts/tests.py

@@ -26,7 +26,7 @@ from django.db import ConnectionHandler
 from django.db.migrations.exceptions import MigrationSchemaMissing
 from django.db.migrations.recorder import MigrationRecorder
 from django.test import (
-    LiveServerTestCase, SimpleTestCase, mock, override_settings,
+    LiveServerTestCase, SimpleTestCase, TestCase, mock, override_settings,
 )
 from django.test.runner import DiscoverRunner
 from django.utils._os import npath, upath
@@ -1383,6 +1383,36 @@ class ManageRunserver(AdminScriptTestCase):
         self.assertIn("Not checking migrations", self.output.getvalue())
 
 
+class ManageRunserverMigrationWarning(TestCase):
+
+    def setUp(self):
+        from django.core.management.commands.runserver import Command
+        self.stdout = StringIO()
+        self.runserver_command = Command(stdout=self.stdout)
+
+    @override_settings(INSTALLED_APPS=["admin_scripts.app_waiting_migration"])
+    def test_migration_warning_one_app(self):
+        self.runserver_command.check_migrations()
+        output = self.stdout.getvalue()
+        self.assertIn('You have 1 unapplied migration(s)', output)
+        self.assertIn('apply the migrations for app(s): app_waiting_migration.', output)
+
+    @override_settings(
+        INSTALLED_APPS=[
+            "admin_scripts.app_waiting_migration",
+            "admin_scripts.another_app_waiting_migration",
+        ],
+    )
+    def test_migration_warning_multiple_apps(self):
+        self.runserver_command.check_migrations()
+        output = self.stdout.getvalue()
+        self.assertIn('You have 2 unapplied migration(s)', output)
+        self.assertIn(
+            'apply the migrations for app(s): another_app_waiting_migration, '
+            'app_waiting_migration.', output
+        )
+
+
 class ManageRunserverEmptyAllowedHosts(AdminScriptTestCase):
     def setUp(self):
         self.write_settings('settings.py', sdict={