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 19236 M2M fields should type-check rather than just trying for a split() method Stephen Burrows Stephen Burrows "Original thread: https://groups.google.com/forum/?fromgroups=#!topic/django-developers/ZY9uisJynSI When setting up a relationship between two models, the ""relation"" argument to add_lazy_relation [1] can be either a Model subclass or a string. But the check for whether it's a string is simply ""try calling relation.split(""."")"". If the argument is a Model subclass with a split() method, this fails horribly and unexpectedly. [1] https://github.com/django/django/blob/master/django/db/models/fields/related.py#L25" Bug closed Database layer (models, ORM) 1.5-alpha-1 Normal fixed Accepted 1 0 0 0 1 0