Fix error when no secret file provided for a complex field. (#118)

Author: hramezani

pydantic_settings/sources.py

@@ -83,7 +83,7 @@ def prepare_field_value(self, field_name: str, field: FieldInfo, value: Any, val
         Returns:
             The prepared value.
         """
-        if self.field_is_complex(field) or value_is_complex:
+        if value is not None and (self.field_is_complex(field) or value_is_complex):
             return json.loads(value)
         return value
 

tests/test_settings.py

@@ -1161,14 +1161,16 @@ class Settings(BaseSettings):
 def test_secrets_missing(tmp_path):
     class Settings(BaseSettings):
         foo: str
+        bar: List[str]
 
         model_config = SettingsConfigDict(secrets_dir=tmp_path)
 
     with pytest.raises(ValidationError) as exc_info:
         Settings()
 
     assert exc_info.value.errors(include_url=False) == [
-        {'type': 'missing', 'loc': ('foo',), 'msg': 'Field required', 'input': {}}
+        {'type': 'missing', 'loc': ('foo',), 'msg': 'Field required', 'input': {}},
+        {'input': {}, 'loc': ('bar',), 'msg': 'Field required', 'type': 'missing'},
     ]