#36183: Model o2o inheritance with abstract models does not "evaluate" a lazy
relationship
-------------------------------------+-------------------------------------
     Reporter:  BeryCZ               |                    Owner:  (none)
         Type:  Bug                  |                   Status:  closed
    Component:  Database layer       |                  Version:  5.1
  (models, ORM)                      |
     Severity:  Normal               |               Resolution:  invalid
     Keywords:                       |             Triage Stage:
                                     |  Unreviewed
    Has patch:  0                    |      Needs documentation:  0
  Needs tests:  0                    |  Patch needs improvement:  0
Easy pickings:  0                    |                    UI/UX:  0
-------------------------------------+-------------------------------------
Comment (by Simon Charette):

 So I tried adapting `BaseModel.__new__` to confirm this was effectively
 never supported with

 {{{#!diff
 diff --git a/django/db/models/base.py b/django/db/models/base.py
 index 575365e11c..5a33f78a98 100644
 --- a/django/db/models/base.py
 +++ b/django/db/models/base.py
 @@ -243,7 +243,17 @@ def __new__(cls, name, bases, attrs, **kwargs):
              for field in base._meta.local_fields:
                  if isinstance(field, OneToOneField) and
 field.remote_field.parent_link:
                      related = resolve_relation(new_class,
 field.remote_field.model)
 -                    parent_links[make_model_tuple(related)] = field
 +                    related_model_tuple = make_model_tuple(related)
 +                    if abstract and not any(
 +                        make_model_tuple(parent) == related_model_tuple
 +                        for parent in parents
 +                        if hasattr(parent, "_meta")
 +                    ):
 +                        raise TypeError(
 +                            "Abstract models must directly inherit from
 parent "
 +                            "links they refer to."
 +                        )
 +                    parent_links[related_model_tuple] = field

          # Track fields inherited from base models.
          inherited_attributes = set()
 }}}

 And the suited failed on
 
[https://github.com/django/django/blob/47c837a1ff96ef1b10b44477a7a9f72283d12e83/tests/model_inheritance_regress/models.py#L37-L50
 these models] which `git-blame` led me to #20883
 (163a34ce4bc1086b346a52c7271f48d2c207f710) which makes me believe this
 either never fully worked (notice the tests are very minimal) or that the
 latest changes to abstract model inheritance field attribution in #24305
 (85ef98dc6ec565b1add417bd76808664e7318026).

 Given we have models in the suite I think we should at least bisect to
 determine if this was ever properly supported but so minimally tested that
 #24305 silently broke it. If it never truly worked then I'd suggest we add
 this `TypeError` otherwise if it was broken by #24305 we should consider
 it like a long standing regression.
-- 
Ticket URL: <https://code.djangoproject.com/ticket/36183#comment:4>
Django <https://code.djangoproject.com/>
The Web framework for perfectionists with deadlines.

-- 
You received this message because you are subscribed to the Google Groups 
"Django updates" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to [email protected].
To view this discussion visit 
https://groups.google.com/d/msgid/django-updates/01070194fd1ab915-da16373c-3c82-41cd-874b-ff37beefc185-000000%40eu-central-1.amazonses.com.

Reply via email to