{"record":{"id":"e12bb059e8493c28","repo":"pypa/pip","slug":"cannot-restore-specifier-from-state-r","errorCode":null,"errorMessage":"Cannot restore Specifier from {state!r}","messagePattern":"Cannot restore Specifier from (.+?)","errorType":"exception","errorClass":"TypeError","httpStatus":null,"severity":"error","filePath":"src/pip/_vendor/packaging/specifiers.py","lineNumber":502,"sourceCode":"            if len(state) == 2 and isinstance(state[1], dict):\n                # Format (packaging 26.0-26.1): (None, {slot: value}).\n                _, slot_dict = state\n                spec = slot_dict.get(\"_spec\")\n                prereleases = slot_dict.get(\"_prereleases\", \"invalid\")\n                if _validate_spec(spec) and _validate_pre(prereleases):\n                    self._spec = spec\n                    self._prereleases = prereleases\n                    return\n        if isinstance(state, dict):\n            # Old format (packaging <= 25.x, no __slots__): state is a plain dict.\n            spec = state.get(\"_spec\")\n            prereleases = state.get(\"_prereleases\", \"invalid\")\n            if _validate_spec(spec) and _validate_pre(prereleases):\n                self._spec = spec\n                self._prereleases = prereleases\n                return\n\n        raise TypeError(f\"Cannot restore Specifier from {state!r}\")\n\n    @property\n    def operator(self) -> str:\n        \"\"\"The operator of this specifier.\n\n        >>> Specifier(\"==1.2.3\").operator\n        '=='\n        \"\"\"\n        return self._spec[0]\n\n    @property\n    def version(self) -> str:\n        \"\"\"The version of this specifier.\n\n        >>> Specifier(\"==1.2.3\").version\n        '1.2.3'\n        \"\"\"\n        return self._spec[1]","sourceCodeStart":484,"sourceCodeEnd":520,"githubUrl":"https://github.com/pypa/pip/blob/f399c3718970b1b0e2478dac5296eb62679a9b86/src/pip/_vendor/packaging/specifiers.py#L484-L520","documentation":"Raised as TypeError by Specifier.__setstate__ (specifiers.py:502) during unpickling when the saved pickle state does not match any recognized layout. __setstate__ tries three formats in order: the 26.2+ tuple ((operator, version), prereleases), the 26.0-26.1 slot dict (None, {slot: value}), and the <=25.x plain dict; if _validate_spec/_validate_pre reject all three, this is raised. It indicates a pickle produced by an incompatible packaging version or hand-crafted/corrupt state.","triggerScenarios":"pickle.loads() of a Specifier pickled under packaging <=25.x being loaded under 26.2+ where the dict no longer carries the expected keys (or vice versa); copying a Specifier through a multiprocessing queue between processes with different packaging versions; constructing a fake pickle payload with a malformed state tuple.","commonSituations":"Cross-version deployment: a worker process on packaging 24.x writes Specifier pickles to a cache/queue, a consumer on 26.x reads them and the layout has shifted; caching resolved specifiers in a persistent store across a packaging upgrade; environments with vendored vs. system packaging differing.","solutions":["Re-serialize the Specifier by storing str(spec) (which round-trips) instead of pickling the object, and reconstruct via Specifier(str_repr) on load.","Align packaging versions on both sides of the pickle boundary (producer and consumer) so the state layout matches.","Clear/flush any persistent pickle cache (disk cache, memcached, multiprocessing queues) after upgrading packaging.","If you must pickle, catch TypeError in __setstate__ consumers and fall back to re-creating from the string form."],"exampleFix":"# before - pickle the object directly (fragile across versions)\nimport pickle\nblob = pickle.dumps(Specifier('>=1.0.0'))\nspec = pickle.loads(blob)  # TypeError after a packaging upgrade\n\n# after - persist the round-trippable string\nfrom packaging.specifiers import Specifier\nblob = str(Specifier('>=1.0.0')).encode()  # b'>=1.0.0'\nspec = Specifier(blob.decode())","handlingStrategy":"fallback","validationCode":"# Before unpickling, prefer the round-trippable string form.\n# If you have a string, never pickle the object:\nfrom packaging.specifiers import Specifier\ndef load_specifier(s: str) -> 'Specifier':\n    return Specifier(s)","typeGuard":"from packaging.specifiers import Specifier\ndef is_specifier_state(state) -> bool:\n    return (isinstance(state, tuple) and len(state) == 2\n            and isinstance(state[0], tuple) and len(state[0]) == 2\n            and all(isinstance(x, str) for x in state[0])\n            and (state[1] is None or isinstance(state[1], bool)))","tryCatchPattern":"import pickle\ntry:\n    spec = pickle.loads(blob)\nexcept TypeError:\n    spec = Specifier(blob.decode())  # fallback if blob is the string form","preventionTips":["Never pickle Specifier across packaging versions; persist str(spec) instead.","Align packaging versions across all processes that exchange pickles.","Flush pickle caches after any packaging upgrade."],"tags":["packaging","specifiers","pickle","serialization","version-mismatch"],"backgroundTag":null,"analyzedSha":"f399c3718970b1b0e2478dac5296eb62679a9b86","analyzedAt":"2026-08-08T23:01:42.227Z","contentChangedAt":null,"schemaVersion":2},"datasetVersion":"2026-09-23T08:17:48.524Z"}