{"record":{"id":"7ae3ff76647bb937","repo":"langchain-ai/langgraph","slug":"extension-name-must-be-non-empty","errorCode":null,"errorMessage":"extension name must be non-empty.","messagePattern":"extension name must be non-empty\\.","errorType":"exception","errorClass":"ValueError","httpStatus":null,"severity":"error","filePath":"libs/sdk-py/langgraph_sdk/_async/stream.py","lineNumber":1113,"sourceCode":"            self._thread._unregister_subscription(sub.id)\n\n\nclass _ExtensionsProjection:\n    \"\"\"Mapping from extension name to custom event payload stream.\n\n    Repeated access for the same `name` returns the cached projection so that\n    callers receive the same subscription handle across multiple references to\n    `thread.extensions[\"foo\"]` within one session.\n    \"\"\"\n\n    def __init__(self, thread: AsyncThreadStream, namespace: list[str]) -> None:\n        self._thread = thread\n        self._namespace = namespace\n        self._cache: dict[str, _ExtensionProjection] = {}\n\n    def __getitem__(self, name: str) -> _ExtensionProjection:\n        if not name:\n            raise ValueError(\"extension name must be non-empty.\")\n        if name not in self._cache:\n            self._cache[name] = _ExtensionProjection(\n                self._thread, name=name, namespace=self._namespace\n            )\n        return self._cache[name]\n\n\nclass _ExtensionProjection:\n    def __init__(\n        self,\n        thread: AsyncThreadStream,\n        *,\n        name: str,\n        namespace: list[str],\n    ) -> None:\n        self._thread = thread\n        self._name = name\n        self._namespace = namespace","sourceCodeStart":1095,"sourceCodeEnd":1131,"githubUrl":"https://github.com/langchain-ai/langgraph/blob/38031739e551638e373fb553453256c23feeb41f/libs/sdk-py/langgraph_sdk/_async/stream.py#L1095-L1131","documentation":"Error \"extension name must be non-empty.\" thrown in langchain-ai/langgraph.","triggerScenarios":"Thrown at libs/sdk-py/langgraph_sdk/_async/stream.py:1113 when the library encounters an invalid state.","commonSituations":"See trigger scenarios.","solutions":[],"exampleFix":null,"handlingStrategy":null,"validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":[],"tags":[],"backgroundTag":null,"analyzedSha":"38031739e551638e373fb553453256c23feeb41f","analyzedAt":"2026-08-26T18:02:49.312Z","schemaVersion":2},"datasetVersion":"2026-08-26T21:11:00.512Z"}