Error E108 does not cover some cases

[Baha Sdtbekov]

I have two models, Question and Choice. And if I write list_display = ["choice"] in QuestionAdmin, I get no errors.
But when I visit /admin/polls/question/, the following trace is returned:

Internal Server Error: /admin/polls/question/
Traceback (most recent call last):
  File "/some/path/django/contrib/admin/utils.py", line 334, in label_for_field
    field = _get_non_gfk_field(model._meta, name)
  File "/some/path/django/contrib/admin/utils.py", line 310, in _get_non_gfk_field
    raise FieldDoesNotExist()
django.core.exceptions.FieldDoesNotExist

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/some/path/django/core/handlers/exception.py", line 55, in inner
    response = get_response(request)
  File "/some/path/django/core/handlers/base.py", line 220, in _get_response
    response = response.render()
  File "/some/path/django/template/response.py", line 111, in render
    self.content = self.rendered_content
  File "/some/path/django/template/response.py", line 89, in rendered_content
    return template.render(context, self._request)
  File "/some/path/django/template/backends/django.py", line 61, in render
    return self.template.render(context)
  File "/some/path/django/template/base.py", line 175, in render
    return self._render(context)
  File "/some/path/django/template/base.py", line 167, in _render
    return self.nodelist.render(context)
  File "/some/path/django/template/base.py", line 1005, in render
    return SafeString("".join([node.render_annotated(context) for node in self]))
  File "/some/path/django/template/base.py", line 1005, in <listcomp>
    return SafeString("".join([node.render_annotated(context) for node in self]))
  File "/some/path/django/template/base.py", line 966, in render_annotated
    return self.render(context)
  File "/some/path/django/template/loader_tags.py", line 157, in render
    return compiled_parent._render(context)
  File "/some/path/django/template/base.py", line 167, in _render
    return self.nodelist.render(context)
  File "/some/path/django/template/base.py", line 1005, in render
    return SafeString("".join([node.render_annotated(context) for node in self]))
  File "/some/path/django/template/base.py", line 1005, in <listcomp>
    return SafeString("".join([node.render_annotated(context) for node in self]))
  File "/some/path/django/template/base.py", line 966, in render_annotated
    return self.render(context)
  File "/some/path/django/template/loader_tags.py", line 157, in render
    return compiled_parent._render(context)
  File "/some/path/django/template/base.py", line 167, in _render
    return self.nodelist.render(context)
  File "/some/path/django/template/base.py", line 1005, in render
    return SafeString("".join([node.render_annotated(context) for node in self]))
  File "/some/path/django/template/base.py", line 1005, in <listcomp>
    return SafeString("".join([node.render_annotated(context) for node in self]))
  File "/some/path/django/template/base.py", line 966, in render_annotated
    return self.render(context)
  File "/some/path/django/template/loader_tags.py", line 63, in render
    result = block.nodelist.render(context)
  File "/some/path/django/template/base.py", line 1005, in render
    return SafeString("".join([node.render_annotated(context) for node in self]))
  File "/some/path/django/template/base.py", line 1005, in <listcomp>
    return SafeString("".join([node.render_annotated(context) for node in self]))
  File "/some/path/django/template/base.py", line 966, in render_annotated
    return self.render(context)
  File "/some/path/django/template/loader_tags.py", line 63, in render
    result = block.nodelist.render(context)
  File "/some/path/django/template/base.py", line 1005, in render
    return SafeString("".join([node.render_annotated(context) for node in self]))
  File "/some/path/django/template/base.py", line 1005, in <listcomp>
    return SafeString("".join([node.render_annotated(context) for node in self]))
  File "/some/path/django/template/base.py", line 966, in render_annotated
    return self.render(context)
  File "/some/path/django/contrib/admin/templatetags/base.py", line 45, in render
    return super().render(context)
  File "/some/path/django/template/library.py", line 258, in render
    _dict = self.func(*resolved_args, **resolved_kwargs)
  File "/some/path/django/contrib/admin/templatetags/admin_list.py", line 326, in result_list
    headers = list(result_headers(cl))
  File "/some/path/django/contrib/admin/templatetags/admin_list.py", line 90, in result_headers
    text, attr = label_for_field(
  File "/some/path/django/contrib/admin/utils.py", line 362, in label_for_field
    raise AttributeError(message)
AttributeError: Unable to lookup 'choice' on Question or QuestionAdmin
[24/Apr/2023 15:43:32] "GET /admin/polls/question/ HTTP/1.1" 500 349913

I suggest that error E108 be updated to cover this case as well

For reproduce see ​github

[Baha Sdtbekov]

I think I will make a bug fix later if required

[David Sanders]

Thanks bakdolot 👍

There's a slight difference between a model instance's attributes and the model class' meta's fields. Meta stores the reverse relationship as choice, where as this would be setup & named according to whatever the related_name is declared as.

[David Sanders]

fyi potential quick fix, this will cause it to start raising E108 errors.

this is just a demo of where to look. One possibility we could abandon using get_field() and refer to _meta.fields instead? 🤔… though that would mean the E109 check below this would no longer work.

django/contrib/admin/checks.py

@@ -9 +9 @@
 from django.db import models
 from django.db.models.constants import LOOKUP_SEP
 from django.db.models.expressions import Combinable
+from django.db.models.fields.reverse_related import ManyToOneRel
 from django.forms.models import BaseModelForm, BaseModelFormSet, _get_foreign_key
 from django.template import engines
 from django.template.backends.django import DjangoTemplates
@@ -897 +898 @@
             return []
         try:
             field = obj.model._meta.get_field(item)
+            if isinstance(field, ManyToOneRel):
+                raise FieldDoesNotExist
         except FieldDoesNotExist:
             try:
                 field = getattr(obj.model, item)

[Natalia Bidart]

This is related to the recent work merged for ticket:34481.

[David Sanders]

@nessita yup I recognised bakdolot's username from that patch :D

[Baha Sdtbekov]

Oh no they recognized me :D

I apologize very much. I noticed this bug only after merge when I decided to check again

By the way, I also noticed two bugs related to this

[Baha Sdtbekov]

I checked most of the fields and found these fields that are not working correctly

class QuestionAdmin(admin.ModelAdmin):
    list_display = ["choice", "choice_set", "somem2m", "SomeM2M_question+", "somem2m_set", "__module__", "__doc__", "objects"]

Also for reproduce see ​github

[Mariusz Felisiak]

Replying to Baha Sdtbekov:

I checked most of the fields and found these fields that are not working correctly

class QuestionAdmin(admin.ModelAdmin):
    list_display = ["choice", "choice_set", "somem2m", "SomeM2M_question+", "somem2m_set", "__module__", "__doc__", "objects"]

Also for reproduce see ​github

System checks are helpers that in this case should highlight potentially reasonable but unsupported options. IMO they don't have to catch all obviously wrong values that you can find in __dir__.

[David Sanders]

Yup agreed with felixx if they're putting __doc__ in there then they probably need to go back and do a Python tutorial :)

As for choice_set & somem2m – I thought that's what you fixed up in the other patch with E109.

[Baha Sdtbekov]

​PR

[GitHub <noreply@…>]

In c61219a7:

Fixed #34513 -- Added system check for relational fields in ModelAdmin.list_display.