#29893: Unexpected behavior of DetailView on a model defining __len__()
returning
False
-------------------------------+--------------------------------------
Reporter: Max | Owner: Max
Type: Bug | Status: assigned
Component: Generic views | Version: 2.1
Severity: Normal | Resolution:
Keywords: | Triage Stage: Unreviewed
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 Simon Charette):
I guess adding an `is None` would do for this case but I wouldn't be
surprised if a lot of other cases still break. For example, there's
probably a few model forms or admin APIs that do something along `if
self.instance` and would need to be adjusted as well.
Given defining `__len__()` on a model instance is an edge case and your
issue can be worked around by defining a `def __bool__(self): return True`
I'm tempted to close this issue as _wont fix_ but I'll let other
contributors chime in. I feel like the burden of making sure all APIs
dealing with optional model instances truthiness appropriately is not
worth the small benefit here.
--
Ticket URL: <https://code.djangoproject.com/ticket/29893#comment:2>
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