Fix nested model AliasChoices in validation alias (#411)

pydantic_settings/sources.py

@@ -778,8 +778,9 @@ def _field_is_complex(self, field: FieldInfo) -> tuple[bool, bool]:
  # Default value of `case_sensitive` is `None`, because we don't want to break existing behavior.
  # We have to change the method to a non-static method and use
  # `self.case_sensitive` instead in V3.
- @staticmethod
- def next_field(field: FieldInfo | Any | None, key: str, case_sensitive: bool | None = None) -> FieldInfo | None:
+ def next_field(
+ self, field: FieldInfo | Any | None, key: str, case_sensitive: bool | None = None
+ ) -> FieldInfo | None:
  """
  Find the field in a sub model by key(env name)
 
@@ -815,21 +816,20 @@ class Cfg(BaseSettings):
  annotation = field.annotation if isinstance(field, FieldInfo) else field
  if origin_is_union(get_origin(annotation)) or isinstance(annotation, WithArgsTypes):
  for type_ in get_args(annotation):
- type_has_key = EnvSettingsSource.next_field(type_, key, case_sensitive)
+ type_has_key = self.next_field(type_, key, case_sensitive)
  if type_has_key:
  return type_has_key
  elif is_model_class(annotation) or is_pydantic_dataclass(annotation):
  fields = _get_model_fields(annotation)
  # `case_sensitive is None` is here to be compatible with the old behavior.
  # Has to be removed in V3.
  for field_name, f in fields.items():
- if case_sensitive is None or case_sensitive:
- if (field_name == key) or (isinstance(f.validation_alias, str) and f.validation_alias == key):
+ for _, env_name, _ in self._extract_field_info(f, field_name):
+ if case_sensitive is None or case_sensitive:
+ if field_name == key or env_name == key:
+ return f
+ elif field_name.lower() == key.lower() or env_name.lower() == key.lower():
  return f
- elif (field_name.lower() == key.lower()) or (
- isinstance(f.validation_alias, str) and f.validation_alias.lower() == key.lower()
- ):
- return f
  return None
 
  def explode_env_vars(self, field_name: str, field: FieldInfo, env_vars: Mapping[str, str | None]) -> dict[str, Any]:

tests/test_settings.py

@@ -5090,3 +5090,18 @@ class Settings(BaseSettings):
  monkeypatch.setattr(os, 'environ', value={'nested__fooAlias': '["one", "two"]'})
  s = Settings()
  assert s.model_dump() == {'nested': {'foo': ['one', 'two']}}
+
+
+def test_nested_model_field_with_alias_choices(env):
+ class NestedSettings(BaseModel):
+ foo: List[str] = Field(alias=AliasChoices('fooalias', 'foo-alias'))
+
+ class Settings(BaseSettings):
+ model_config = SettingsConfigDict(env_nested_delimiter='__')
+
+ nested: NestedSettings
+
+ env.set('nested__fooalias', '["one", "two"]')
+
+ s = Settings()
+ assert s.model_dump() == {'nested': {'foo': ['one', 'two']}}