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@@ -218,6 +218,26 @@ Apps without migrations must not have relations (``ForeignKey``,
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``ManyToManyField``, etc.) to apps with migrations. Sometimes it may work, but
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it's not supported.
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+Swappable dependencies
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+----------------------
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+
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+.. function:: django.db.migrations.swappable_dependency(value)
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+
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+The ``swappable_dependency()`` function is used in migrations to declare
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+"swappable" dependencies on migrations in the app of the swapped-in model.
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+Currently, the first migration of this app and as a consequence the swapped-in
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+model should be created in the initial migration. The argument ``value`` is a
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+string ``"<app label>.<model>"`` describing an app label and a model name, e.g.
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+``"myapp.MyModel"``.
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+
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+By using ``swappable_dependency()``, you inform the migration framework that
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+the migration relies on a migration which sets up up a swappable model,
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+allowing for the possibility of substituting the model with a different
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+implementation in the future. This is typically used for referencing models
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+that are subject to customization or replacement, such as the custom user
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+model (``settings.AUTH_USER_MODEL``, which defaults to ``"auth.User"``) in
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+Django's authentication system.
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+
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.. _migration-files:
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Migration files
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DevilsAutumn