#28394: BaseExpression.output_field is resolved incorrectly if source
expressions
have directly set output_field
-------------------------------------+-------------------------------------
Reporter: Sergey | Owner: nobody
Fedoseev |
Type: Bug | Status: new
Component: Database | Version: 1.11
layer (models, ORM) |
Severity: Normal | Keywords:
Triage Stage: | Has patch: 0
Unreviewed |
Needs documentation: 0 | Needs tests: 0
Patch needs improvement: 0 | Easy pickings: 0
UI/UX: 0 |
-------------------------------------+-------------------------------------
{{{
In [1]: from django.db import models
In [2]: from django.db.models.expressions import Func
In [3]: class FuncA(Func):
...: output_field = models.CharField()
...:
In [4]: class FuncB(Func):
...: pass
...:
In [5]: expr = FuncB(FuncA(models.IntegerField()))
In [6]: expr.output_field
---------------------------------------------------------------------------
FieldError Traceback (most recent call
last)
<ipython-input-6-ac0033dafa8f> in <module>()
----> 1 expr.output_field
/home/sergey/dev/django/django/utils/functional.py in __get__(self,
instance, cls)
34 if instance is None:
35 return self
---> 36 res = instance.__dict__[self.name] = self.func(instance)
37 return res
38
/home/sergey/dev/django/django/db/models/expressions.py in
output_field(self)
225 """Return the output type of this expressions."""
226 if self._output_field_or_none is None:
--> 227 raise FieldError("Cannot resolve expression type,
unknown output_field")
228 return self._output_field_or_none
229
FieldError: Cannot resolve expression type, unknown output_field
}}}
--
Ticket URL: <https://code.djangoproject.com/ticket/28394>
Django <https://code.djangoproject.com/>
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