From 079f3243577be01068543a43d1bfb42bcf84b8b3 Mon Sep 17 00:00:00 2001
From: Sanket Saurav <sanketsaurav@gmail.com>
Date: Sat, 5 May 2018 17:03:20 +0530
Subject: [PATCH] Fixed #28913 -- Fixed error handling when MIGRATIONS_MODULES
 specifies a nonexistent top-level package.

---
 AUTHORS                           |  1 +
 django/db/migrations/writer.py    |  2 +-
 tests/migrations/test_commands.py | 10 ++++++++++
 3 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/AUTHORS b/AUTHORS
index ff7763b2fd..91d572d78b 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -722,6 +722,7 @@ answer newbie questions, and generally made Django that much better:
     Ryno Mathee <rmathee@gmail.com>
     Sam Newman <http://www.magpiebrain.com/>
     Sander Dijkhuis <sander.dijkhuis@gmail.com>
+    Sanket Saurav <sanketsaurav@gmail.com>
     Sarthak Mehrish <sarthakmeh03@gmail.com>
     schwank@gmail.com
     Scot Hacker <shacker@birdhouse.org>
diff --git a/django/db/migrations/writer.py b/django/db/migrations/writer.py
index aa296db8c5..d056e00646 100644
--- a/django/db/migrations/writer.py
+++ b/django/db/migrations/writer.py
@@ -240,7 +240,7 @@ class MigrationWriter:
             missing_dirs.insert(0, existing_dirs.pop(-1))
             try:
                 base_module = import_module(".".join(existing_dirs))
-            except ImportError:
+            except (ImportError, ValueError):
                 continue
             else:
                 try:
diff --git a/tests/migrations/test_commands.py b/tests/migrations/test_commands.py
index 8a77624e34..933c00eada 100644
--- a/tests/migrations/test_commands.py
+++ b/tests/migrations/test_commands.py
@@ -1116,6 +1116,16 @@ class MakeMigrationsTests(MigrationTestBase):
         # Command output indicates the migration is created.
         self.assertIn(" - Create model SillyModel", out.getvalue())
 
+    @override_settings(MIGRATION_MODULES={'migrations': 'some.nonexistent.path'})
+    def test_makemigrations_migrations_modules_nonexistent_toplevel_package(self):
+        msg = (
+            'Could not locate an appropriate location to create migrations '
+            'package some.nonexistent.path. Make sure the toplevel package '
+            'exists and can be imported.'
+        )
+        with self.assertRaisesMessage(ValueError, msg):
+            call_command('makemigrations', 'migrations', empty=True, verbosity=0)
+
     def test_makemigrations_interactive_by_default(self):
         """
         The user is prompted to merge by default if there are conflicts and