{"record":{"id":"29c7b34c6dee2602","repo":"reflex-dev/reflex","slug":"the-var-full-name-needs-state-prefix-argument-is","errorCode":null,"errorMessage":"The _var_full_name_needs_state_prefix argument is not supported for Var.","messagePattern":"The _var_full_name_needs_state_prefix argument is not supported for Var\\.","errorType":"exception","errorClass":"TypeError","httpStatus":null,"severity":"error","filePath":"packages/reflex-base/src/reflex_base/vars/base.py","lineNumber":795,"sourceCode":"            **kwargs: Var fields to update.\n\n        Returns:\n            A new Var with the updated fields overwriting the corresponding fields in this Var.\n\n        Raises:\n            TypeError: If _var_is_local, _var_is_string, or _var_full_name_needs_state_prefix is not None.\n        \"\"\"\n        if kwargs.get(\"_var_is_local\", False) is not False:\n            msg = \"The _var_is_local argument is not supported for Var.\"\n            raise TypeError(msg)\n\n        if kwargs.get(\"_var_is_string\", False) is not False:\n            msg = \"The _var_is_string argument is not supported for Var.\"\n            raise TypeError(msg)\n\n        if kwargs.get(\"_var_full_name_needs_state_prefix\", False) is not False:\n            msg = \"The _var_full_name_needs_state_prefix argument is not supported for Var.\"\n            raise TypeError(msg)\n        value_with_replaced = dataclasses.replace(\n            self,\n            _var_type=_var_type or self._var_type,\n            _var_data=VarData.merge(\n                kwargs.get(\"_var_data\", self._var_data), merge_var_data\n            ),\n            **kwargs,\n        )\n\n        if (js_expr := kwargs.get(\"_js_expr\")) is not None:\n            object.__setattr__(value_with_replaced, \"_js_expr\", js_expr)\n\n        return value_with_replaced\n\n    @overload\n    @classmethod\n    def create(  # pyright: ignore[reportOverlappingOverload]\n        cls,","sourceCodeStart":777,"sourceCodeEnd":813,"githubUrl":"https://github.com/reflex-dev/reflex/blob/45b8ed5ab735f8a56bbb09a42384f030eb0208e7/packages/reflex-base/src/reflex_base/vars/base.py#L777-L813","documentation":"Var._replace rejects the legacy keyword _var_full_name_needs_state_prefix. Whether a Var's full name is prefixed with its owning state is now derived from VarData (the state field), so the old boolean flag raises TypeError. Same family as the _var_is_local/_var_is_string guards.","triggerScenarios":"Calling var._replace(_var_full_name_needs_state_prefix=True); internal-style code from older reflex versions; libraries that manipulated state-prefixing via this private flag.","commonSituations":"Upgrading reflex after the VarData refactor; maintaining a fork or component library using private Var internals; porting old compiler code.","solutions":["Remove the kwarg — attach the owning state through VarData instead (VarData(state=...) via the state's var path)","Use the public helpers that create properly-prefixed vars (State.var_name or Var operations on state attributes)","Upgrade third-party packages pinned to old reflex versions","Grep for _var_full_name_needs_state_prefix and migrate every site"],"exampleFix":"# before\nv = v._replace(_var_full_name_needs_state_prefix=True)\n# after\nv = VarData.merge(v._var_data, VarData(state=State)).apply(v)  # prefixing comes from VarData.state","handlingStrategy":"type-guard","validationCode":"kwargs.pop('_var_full_name_needs_state_prefix', None)\nv = v._replace(**kwargs)","typeGuard":"def is_supported_replace_kwarg(name: str) -> bool:\n    return name not in {'_var_is_local', '_var_is_string', '_var_full_name_needs_state_prefix'}","tryCatchPattern":null,"preventionTips":["Derive state-prefixing from VarData, not flags","Keep a migration checklist of private Var flags when upgrading reflex"],"tags":["reflex","var","deprecated-argument","upgrade"],"backgroundTag":"removed-api-argument","analyzedSha":"45b8ed5ab735f8a56bbb09a42384f030eb0208e7","analyzedAt":"2026-08-28T19:25:27.644Z","schemaVersion":2},"datasetVersion":"2026-08-28T21:17:43.275Z"}