id,summary,reporter,owner,description,type,status,component,version,severity,resolution,keywords,cc,stage,has_patch,needs_docs,needs_tests,needs_better_patch,easy,ui_ux 25214,Behavior of _meta.auto_created = True in m2m through model is not expected.,Chaoyi Du,nobody,"I have models like: {{{ class A(models.Model): ... b = models.ManyToManyField( 'B', through='Through', ) ... class B(models.Model): ... class Through(models.Model): a = models.ForeignKey('A') b = models.ForeignKey('B') ... # other fields have default value class Meta: auto_created = False }}} If I make migrations at this point, joint table 'Through' will be created. Then if I set ""Through._meta.auto_created = True"" somewhere, and never update migrations. Everything works well. If I add a new relationship between A instance and B instance, a through object will be created with default value, which looks great. However if I update migrations, the ""Through"" model will be removed in migrations and everything break. I think a through model with auto_created=True should be kept in migrations and when new relationships created, through objects shall be created with claimed default value. ",Bug,closed,Migrations,1.8,Normal,needsinfo,,,Unreviewed,0,0,0,0,0,0