[1.7.x] Fixed #22660: Doc'd you can't have unmigrated apps depend on migrated

1 files changed, 15 insertions, 0 deletions

diff --git a/docs/topics/migrations.txt b/docs/topics/migrations.txt
index 40ce520a03..a4fc5c9e52 100644
--- a/docs/topics/migrations.txt
+++ b/docs/topics/migrations.txt
@@ -201,6 +201,21 @@ restrict to a single app. Restricting to a single app (either in
 a guarantee; any other apps that need to be used to get dependencies correct
 will be.
 
+.. _unmigrated-dependencies:
+
+Be aware, however, that unmigrated apps cannot depend on migrated apps, by the
+very nature of not having migrations. This means that it is not generally
+possible to have an unmigrated app have a ForeignKey or ManyToManyField to
+a migrated app; some cases may work, but it will eventually fail.
+
+This is particularly apparent if you use swappable models (e.g.
+``AUTH_USER_MODEL``), as every app that uses swappable models will need
+to have migrations if you're unlucky. As time goes on, more and more
+third-party apps will get migrations, but in the meantime you can either
+give them migrations yourself (using :setting:`MIGRATION_MODULES` to
+store those modules outside of the app's own module if you wish), or
+keep the app with your user model unmigrated.
+
 .. _migration-files:
 
 Migration files