Split non_db_attrs across the fields that introduce them

Field.non_db_attrs used to list every non-db kwarg from every subclass
(choices, limit_choices_to, on_delete, related_query_name). Each class
now declares only its own kwargs and extends its parent's tuple, so the
base no longer hardcodes knowledge of subclass parameters.

Author: davegaeddert

plain-postgres/plain/postgres/fields/base.py

@@ -137,16 +137,12 @@ class Field[T](RegisterLookupMixin):
         "unique": "A %(model_name)s with this %(field_label)s already exists.",
     }
 
-    # Attributes that don't affect a column definition.
-    # These attributes are ignored when altering the field.
-    non_db_attrs = (
+    # Kwargs that don't affect the column definition; the schema editor
+    # ignores these when deciding whether an ALTER is needed. Subclasses
+    # that introduce additional non-db kwargs extend this tuple.
+    non_db_attrs: tuple[str, ...] = (
         "required",
-        "choices",
         "error_messages",
-        "limit_choices_to",
-        # Database-level options are not supported, see #21961.
-        "on_delete",
-        "related_query_name",
         "validators",
     )
 
@@ -733,6 +729,8 @@ def value_from_object(self, obj: Model) -> T | None:
 class ChoicesField[T](Field[T]):
     """Base for fields that accept a ``choices=`` parameter."""
 
+    non_db_attrs = (*Field.non_db_attrs, "choices")
+
     default_error_messages = {
         "invalid_choice": "Value %(value)r is not a valid choice.",
     }

plain-postgres/plain/postgres/fields/related.py

@@ -96,6 +96,8 @@ def lazy_related_operation(
 class RelatedField(FieldCacheMixin, Field):
     """Base class that all relational fields inherit from."""
 
+    non_db_attrs = (*Field.non_db_attrs, "limit_choices_to", "related_query_name")
+
     # RelatedField always has a remote_field (never None)
     remote_field: ForeignObjectRel
     # path_infos is implemented as @cached_property in subclasses (ForeignKey, ManyToManyField)
@@ -367,6 +369,8 @@ class ForeignKeyField(RelatedField):
     ForeignKeyField targets the primary key (id) of the remote model.
     """
 
+    non_db_attrs = (*RelatedField.non_db_attrs, "on_delete")
+
     empty_strings_allowed = False
     default_error_messages = {
         "invalid": "%(model)s instance with %(field)s %(value)r does not exist."