fix(compat): Use ForeignObjectRel.hidden field from django 5.1

.github/workflows/test.yml

@@ -46,11 +46,13 @@ jobs:
     strategy:
       matrix:
         python: ["3.9", "3.10", "3.11", "3.12"]
-        django: ["4.2", "5.0"]
+        django: ["4.2", "5.0", "5.1"]
         database: ["sqlite", "postgres", "mysql"]
         exclude:
           - python: 3.9
             django: 5.0
+          - python: 3.9
+            django: 5.1
     env:
       GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
       DJANGO: ${{ matrix.django }}

modeltranslation/_compat.py

@@ -0,0 +1,31 @@
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+
+import django
+
+if TYPE_CHECKING:
+    from django.db.models.fields.reverse_related import ForeignObjectRel
+
+
+def is_hidden(field: ForeignObjectRel) -> bool:
+    return field.hidden
+
+
+def clear_ForeignObjectRel_caches(field: ForeignObjectRel):
+    """
+    Django 5.1 Introduced caching for `accessor_name` props.
+
+    We need to clear this cache when creating Translated field.
+
+    https://github.com/django/django/commit/5e80390add100e0c7a1ac8e51739f94c5d706ea3#diff-e65b05ecbbe594164125af53550a43ef8a174f80811608012bc8e9e4ed575749
+    """
+    caches = ("accessor_name",)
+    for name in caches:
+        field.__dict__.pop(name, None)
+
+
+if django.VERSION <= (5, 1):
+
+    def is_hidden(field: ForeignObjectRel) -> bool:
+        return field.is_hidden()

modeltranslation/fields.py

@@ -23,6 +23,7 @@
 from modeltranslation.widgets import ClearableWidgetWrapper
 
 from ._typing import Self
+from ._compat import is_hidden, clear_ForeignObjectRel_caches
 
 SUPPORTED_FIELDS = (
     fields.CharField,
@@ -173,6 +174,9 @@ def __init__(
         # (will show up e.g. in the admin).
         self.verbose_name = build_localized_verbose_name(translated_field.verbose_name, language)
 
+        if self.remote_field:
+            clear_ForeignObjectRel_caches(self.remote_field)
+
         # M2M support - <rewrite related_name> <patch intermediary model>
         if isinstance(self.translated_field, fields.related.ManyToManyField) and hasattr(
             self.remote_field, "through"
@@ -187,7 +191,7 @@ def __init__(
                 or self.remote_field.model == self.model
             ):
                 self.remote_field.related_name = "%s_rel_+" % self.name
-            elif self.remote_field.is_hidden():
+            elif is_hidden(self.remote_field):
                 # Even if the backwards relation is disabled, django internally uses it, need to use a language scoped related_name
                 self.remote_field.related_name = "_%s_%s_+" % (
                     self.model.__name__.lower(),
@@ -218,7 +222,7 @@ def __init__(
             if hasattr(self.remote_field.model._meta, "_related_objects_cache"):
                 del self.remote_field.model._meta._related_objects_cache
 
-        elif self.remote_field and not self.remote_field.is_hidden():
+        elif self.remote_field and not is_hidden(self.remote_field):
             current = self.remote_field.get_accessor_name()
             # Since fields cannot share the same rel object:
             self.remote_field = copy.copy(self.remote_field)
@@ -481,17 +485,3 @@ def __set__(self, instance, value):
         loc_field_name = build_localized_fieldname(self.field_name, get_language())
         loc_attname = instance._meta.get_field(loc_field_name).get_attname()
         setattr(instance, loc_attname, value)
-
-
-class LanguageCacheSingleObjectDescriptor:
-    """
-    A Mixin for RelatedObjectDescriptors which use current language in cache lookups.
-    """
-
-    accessor = None  # needs to be set on instance
-
-    def get_cache_name(self) -> str:
-        """
-        Used in django > 2.x
-        """
-        return build_localized_fieldname(self.accessor, get_language())  # type: ignore[arg-type]

modeltranslation/tests/tests.py

@@ -2680,6 +2680,8 @@ class OneToOneFieldModelAdmin(admin.TranslationAdmin):
         fields = ["test_de", "test_en"]
         for field in fields:
             widget = ma.get_form(request).base_fields.get(field).widget
+            # Django 5.1 Adds this attr, ignore it
+            widget.attrs.pop("data-context", None)
             assert {} == widget.attrs
             assert "class" in widget.widget.attrs.keys()
             assert "mt" in widget.widget.attrs["class"]

modeltranslation/translator.py

@@ -21,7 +21,6 @@
 from modeltranslation import settings as mt_settings
 from modeltranslation.fields import (
     NONE,
-    LanguageCacheSingleObjectDescriptor,
     TranslatedManyToManyDescriptor,
     TranslatedRelationIdDescriptor,
     TranslationFieldDescriptor,
@@ -35,11 +34,16 @@
     rewrite_lookup_key,
 )
 from modeltranslation.thread_context import auto_populate_mode
-from modeltranslation.utils import build_localized_fieldname, parse_field
+from modeltranslation.utils import (
+    build_localized_fieldname,
+    parse_field,
+    get_language,
+)
 
 # Re-export the decorator for convenience
 from modeltranslation.decorators import register
 
+from ._compat import is_hidden
 from ._typing import _ListOrTuple
 
 __all__ = [
@@ -458,16 +462,21 @@ def patch_related_object_descriptor_caching(ro_descriptor):
     language-aware caching.
     """
 
-    class NewSingleObjectDescriptor(LanguageCacheSingleObjectDescriptor, ro_descriptor.__class__):
-        pass
+    class NewRelated(ro_descriptor.related.__class__):
+        def get_cache_name(self) -> str:
+            """
+            Used in django > 2.x
+            """
+            return self.cache_name
 
-    ro_descriptor.related.get_cache_name = partial(
-        NewSingleObjectDescriptor.get_cache_name,
-        ro_descriptor,
-    )
+        @property
+        def cache_name(self):
+            """
+            Used in django >= 5.1
+            """
+            return build_localized_fieldname(self.get_accessor_name(), get_language())
 
-    ro_descriptor.accessor = ro_descriptor.related.get_accessor_name()
-    ro_descriptor.__class__ = NewSingleObjectDescriptor
+    ro_descriptor.related.__class__ = NewRelated
 
 
 class Translator:
@@ -599,7 +608,7 @@ def _register_single_model(self, model: type[Model], opts: TranslationOptions) -
                 setattr(model, field.get_attname(), desc)
 
                 # Set related field names on other model
-                if not field.remote_field.is_hidden():
+                if not is_hidden(field.remote_field):
                     other_opts = self._get_options_for_model(field.remote_field.model)
                     other_opts.related = True
                     other_opts.related_fields.append(field.related_query_name())

modeltranslation/utils.py

@@ -4,7 +4,6 @@
 from contextlib import contextmanager
 from typing import Any, TypeVar
 from collections.abc import Generator, Iterable, Iterator
-
 from django.db import models
 from django.utils.encoding import force_str
 from django.utils.functional import lazy