{"record":{"id":"878a463d24914834","repo":"reflex-dev/reflex","slug":"no-default-value-or-factory-provided-878a46","errorCode":null,"errorMessage":"No default value or factory provided.","messagePattern":"No default value or factory provided\\.","errorType":"exception","errorClass":"ValueError","httpStatus":null,"severity":"error","filePath":"packages/reflex-base/src/reflex_base/vars/base.py","lineNumber":3572,"sourceCode":"            for key, value in source_field.__dict__.items():\n                if key not in self.__dict__ and key not in _RESERVED_FIELD_ATTRS:\n                    self.__dict__[key] = value\n\n    def default_value(self) -> FIELD_TYPE | None:\n        \"\"\"Get the default value for the field.\n\n        Returns:\n            The default value for the field.\n\n        Raises:\n            ValueError: If no default value or factory is provided.\n        \"\"\"\n        if self.default is not MISSING:\n            return self.default\n        if self.default_factory is not None:\n            return self.default_factory()\n        msg = \"No default value or factory provided.\"\n        raise ValueError(msg)\n\n    def __repr__(self) -> str:\n        \"\"\"Represent the field in a readable format.\n\n        Returns:\n            The string representation of the field.\n        \"\"\"\n        annotated_type_str = (\n            f\", annotated_type={self.annotated_type!r}\"\n            if self.annotated_type is not MISSING\n            else \"\"\n        )\n        if self.default is not MISSING:\n            return f\"Field(default={self.default!r}, is_var={self.is_var}{annotated_type_str})\"\n        return f\"Field(default_factory={self.default_factory!r}, is_var={self.is_var}{annotated_type_str})\"\n\n    if TYPE_CHECKING:\n","sourceCodeStart":3554,"sourceCodeEnd":3590,"githubUrl":"https://github.com/reflex-dev/reflex/blob/45b8ed5ab735f8a56bbb09a42384f030eb0208e7/packages/reflex-base/src/reflex_base/vars/base.py#L3554-L3590","documentation":"Raised by Field.get_default() when neither a default value nor a default_factory was provided — there is nothing to return.","triggerScenarios":"Calling .get_default() on a Field created with rx.Field() (or dataclasses.field equivalent) with no default/default_factory, typically during state initialization or serialization.","commonSituations":"Custom state fields introspected generically; a Field built only with constraints (gt=, ge=...) and no default, then asked for its default.","solutions":["Provide default=... or default_factory=... when creating the Field","Skip calling get_default() when both default and default_factory are unset (check field.default is MISSING and default_factory is None first)"],"exampleFix":"# before\nfield = rx.Field(ge=0)\nvalue = field.get_default()\n# after\nfield = rx.Field(default=0, ge=0)\nvalue = field.get_default()","handlingStrategy":"validation","validationCode":"if field.default is MISSING and field.default_factory is None:\n    raise ValueError('field has no default')\nvalue = field.get_default()","typeGuard":null,"tryCatchPattern":"try:\n    value = field.get_default()\nexcept ValueError:\n    value = None  # or skip this field","preventionTips":["Always give Fields a default or default_factory","Check field.default/field.default_factory before calling get_default"],"tags":["reflex","field","default-value"],"backgroundTag":"missing-default-value","analyzedSha":"45b8ed5ab735f8a56bbb09a42384f030eb0208e7","analyzedAt":"2026-08-28T19:25:27.644Z","schemaVersion":2},"datasetVersion":"2026-08-28T21:17:43.275Z"}