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Update squashmigration docs to also mention circ dep errs (refs #23337)

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Andrew Godwin 2014-08-21 19:17:25 -07:00
parent 56252e7f46
commit 459cfb523d
1 changed files with 10 additions and 5 deletions
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docs/topics/migrations.txt Normal file → Executable file
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@ -483,11 +483,16 @@ work::
you can delete them.
Note that model interdependencies in Django can get very complex, and squashing
may occasionally result in an optimized migration that doesn't work or is
impossible to run. When this occurs, you can re-try with ``--no-optimize``, but
please `file a bug report <https://code.djangoproject.com/newticket>`_ either
way detailing the models and their relationships so we can improve the
optimizer to handle your case.
may result in migrations that do not run; either mis-optimized (in which case
you can try again with ``--no-optimize``, though you should also report an issue),
or with a ``CircularDependencyError``, in which case you can manually resolve it.
To manually resolve a ``CircularDependencyError``, break out one of
the ForeignKeys in the circular dependency loop into a separate
migration, and move the dependency on the other app with it. If you're unsure,
see how makemigrations deals with the problem when asked to create brand
new migrations from your models. In a future release of Django, squashmigrations
will be updated to attempt to resolve these errors itself.
Once you've squashed your migration, you should then commit it alongside the
migrations it replaces and distribute this change to all running instances