#36611: Model validation of constraint involving ForeignObject considers only
first
column
-------------------------------------+-------------------------------------
Reporter: Jacob Walls | Owner: (none)
Type: Bug | Status: new
Component: Database layer | Version: 5.2
(models, ORM) |
Severity: Release blocker | Resolution:
Keywords: | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
Comment (by Simon Charette):
I suspect this will be very hard to to solve without solving #35956 of the
one ticket I can't find to add generic composite field support as it's
preventing us from performing lookups of the form
{{{#!python
ContactCheck.objects.filter(customer__lt=(1000, "c"))
}}}
in the first place.
Here's an attempt at using `Tuple` which results in the same problem as
`Tuple.output_field` is currently ''faked'' as `models.Field` due to the
lack of `CompositeField` existence
{{{#!diff
diff --git a/django/db/models/base.py b/django/db/models/base.py
index 36b16c1132..d7af0ebd1a 100644
--- a/django/db/models/base.py
+++ b/django/db/models/base.py
@@ -39,6 +39,7 @@
lazy_related_operation,
resolve_relation,
)
+from django.db.models.fields.tuple_lookups import Tuple
from django.db.models.functions import Coalesce
from django.db.models.manager import Manager
from django.db.models.options import Options
@@ -1380,11 +1381,27 @@ def _get_field_expression_map(self, meta,
exclude=None):
isinstance(field.remote_field, ForeignObjectRel)
and field not in meta.local_concrete_fields
):
- value = tuple(
- getattr(self, from_field) for from_field in
field.from_fields
- )
- if len(value) == 1:
- value = value[0]
+ composed_fields = field.local_related_fields
+ if len(composed_fields) == 1:
+ value = getattr(self, composed_fields[0].attname)
+ else:
+ composed_values = (
+ getattr(self, composed_field.attname)
+ for composed_field in composed_fields
+ )
+ value = Tuple(
+ *(
+ (
+ composed_value
+ if hasattr(composed_value,
"resolve_expression")
+ else Value(composed_value,
composed_field)
+ )
+ for composed_value, composed_field in zip(
+ composed_values, composed_fields
+ )
+ ),
+ output_field=field,
+ )
elif field.concrete:
value = getattr(self, field.attname)
else:
}}}
--
Ticket URL: <https://code.djangoproject.com/ticket/36611#comment:6>
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