#23589: Django 1.7 filter Q m2m bug
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     Reporter:  Grafumbly                     |      Owner:  nobody
         Type:  Bug                           |     Status:  new
    Component:  Database layer (models, ORM)  |    Version:  1.7
     Severity:  Normal                        |   Keywords:
 Triage Stage:  Unreviewed                    |  Has patch:  0
Easy pickings:  0                             |      UI/UX:  0
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 The behavior of Q objects has changed in an undocumented and breaking way
 for m2m relationships in Django 1.7 from the behavior in 1.6.7, returning
 different query results depending on the Django version.

 In the case where you want to select a primary object that has related
 objects of one type, but none of another, you could use a Q like this:
 `q = Q(Q(relatedobject__someparam=True),
 ~Q(relatedobject__someparam=False))`
 `results = PrimaryObject.objects.filter(q)`

 Using this Q in a filter in 1.6.7 would give you all primary objects that
 have relatedobjects with someparam=True and omit any primary objects that
 also had a relatedobject with someparam=False. In 1.7 these objects are
 returned despite the ~Q(relatedobject__someparam=False).

 This gist provides a sample to illustrate the problem:
 https://gist.github.com/scottsexton/375f7869839a98593695

--
Ticket URL: <https://code.djangoproject.com/ticket/23589>
Django <https://code.djangoproject.com/>
The Web framework for perfectionists with deadlines.

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