Internal server error: Unknown

[todverse]

Internal Error Stacktrace:

Error Message: Class with name <fields.String(dump_default=<marshmallow.missing>, attribute=None, validate=None, required=False, load_only=False, dump_only=False, load_default=<marshmallow.missing>, allow_none=False, error_messages={'required': 'Missing data for required field.', 'null': 'Field may not be null.', 'validator_failed': 'Invalid value.', 'invalid': 'Not a valid string.', 'invalid_utf8': 'Not a valid utf-8 string.'})> was not found. You may need to import the class.

Traceback (most recent call last):
  File "/opt/hiddify-manager/.venv313/lib/python3.13/site-packages/marshmallow/class_registry.py", line 89, in get_class
    classes = _registry[classname]
  File "/opt/hiddify-manager/.venv313/lib/python3.13/site-packages/apiflask/app.py", line 1366, in _register_schema_and_get_ref
    spec.components.schema(schema_name, schema=schema_obj)
  File "/opt/hiddify-manager/.venv313/lib/python3.13/site-packages/apispec/core.py", line 171, in schema
    ret.update(plugin.schema_helper(component_id, ret, **kwargs) or {})
  File "/opt/hiddify-manager/.venv313/lib/python3.13/site-packages/apispec/ext/marshmallow/__init__.py", line 181, in schema_helper
    schema_instance = resolve_schema_instance(schema)
  File "/opt/hiddify-manager/.venv313/lib/python3.13/site-packages/apispec/ext/marshmallow/common.py", line 29, in resolve_schema_instance
    return marshmallow.class_registry.get_class(schema)()
  File "/opt/hiddify-manager/.venv313/lib/python3.13/site-packages/marshmallow/class_registry.py", line 91, in get_class
    raise RegistryError(
  File "/opt/hiddify-manager/.venv313/lib/python3.13/site-packages/marshmallow/class_registry.py", line 89, in get_class
    classes = _registry[classname]
  File "/opt/hiddify-manager/.venv313/lib/python3.13/site-packages/flask/app.py", line 917, in full_dispatch_request
    rv = self.dispatch_request()
  File "/opt/hiddify-manager/.venv313/lib/python3.13/site-packages/flask/app.py", line 902, in dispatch_request
    return self.ensure_sync(self.view_functions[rule.endpoint])(**view_args)  # type: ignore[no-any-return]
  File "/opt/hiddify-manager/.venv313/lib/python3.13/site-packages/apiflask/app.py", line 1318, in wrapper
    return decorated_func(*args, **kwargs)
  File "/opt/hiddify-manager/.venv313/lib/python3.13/site-packages/apiflask/app.py", line 546, in spec
    response = jsonify(self._get_spec('json'))
  File "/opt/hiddify-manager/.venv313/lib/python3.13/site-packages/apiflask/app.py", line 629, in _get_spec
    spec_object: APISpec = self._generate_spec()
  File "/opt/hiddify-manager/.venv313/lib/python3.13/site-packages/apiflask/app.py", line 1053, in _generate_spec
    self._add_response(
  File "/opt/hiddify-manager/.venv313/lib/python3.13/site-packages/apiflask/app.py", line 1430, in _add_response
    schema = self._register_schema_and_get_ref(spec, registered_schema_classes, schema)
  File "/opt/hiddify-manager/.venv313/lib/python3.13/site-packages/apiflask/app.py", line 1381, in _register_schema_and_get_ref
    spec.components.schema(schema_name, schema=schema_obj)
  File "/opt/hiddify-manager/.venv313/lib/python3.13/site-packages/apispec/core.py", line 171, in schema
    ret.update(plugin.schema_helper(component_id, ret, **kwargs) or {})
  File "/opt/hiddify-manager/.venv313/lib/python3.13/site-packages/apispec/ext/marshmallow/__init__.py", line 181, in schema_helper
    schema_instance = resolve_schema_instance(schema)
  File "/opt/hiddify-manager/.venv313/lib/python3.13/site-packages/apispec/ext/marshmallow/common.py", line 29, in resolve_schema_instance
    return marshmallow.class_registry.get_class(schema)()
  File "/opt/hiddify-manager/.venv313/lib/python3.13/site-packages/marshmallow/class_registry.py", line 91, in get_class
    raise RegistryError(

Details:

Hiddify Version: 12.0.0
Python Version: 3.13.9 (main, Oct 28 2025, 12:10:42) [Clang 20.1.4 ]
OS: Linux-6.8.0-88-generic-x86_64-with-glibc2.39
User Agent: Unknown

[Mkashiii]

In your code, somewhere a marshmallow fields.String() field instance is being used as a response schema directly — e.g.:
python# ❌ Wrong - passing a field instance as a schema
@app.get('/some-route')
@app.output(fields.String()) # or ma.fields.String()
def some_view():
...