#16211: using negated F()-expression in update query
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Reporter: wdoekes | Owner: nobody
Type: New feature | Status: new
Component: Database layer | Version: master
(models, ORM) | Resolution:
Severity: Normal | Triage Stage: Ready for
Keywords: | checkin
Has patch: 1 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
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Comment (by akaariai):
I made some changes to the patch, mostly cosmetic changes to tests and
docs.
However, there was one real problem shown by Python 3 tests - now that F()
objects override `__eq__` they are no longer hashable. This means they are
not usable in sets or as keys in dicts. This can be a problem for users.
If they are currently using F() expressions in sets, they can no longer do
so. In addition this change required some refactoring in
sql/expressions.py which used F() expressions in dicts.
This patch is giving me an uneasy feeling because of the `__eq__` method.
Otherwise I think this should be ready for checkin. We do not have the
option to define other comparison methods except `__eq__`, users will try
to use == anyways if other comparisons are implemented.
Tracked in https://github.com/django/django/pull/405
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Ticket URL: <https://code.djangoproject.com/ticket/16211#comment:20>
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