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Fix crash when TypedDict contains incorrect metadata #853

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Merged
ofek merged 2 commits into from
Oct 20, 2025
Merged

Fix crash when TypedDict contains incorrect metadata #853

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cf96331
Fix crash when TypedDict contains incorrect metadata
JelleZijlstra May 26, 2025
7141899
don't break existing test
JelleZijlstra May 26, 2025
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3 changes: 3 additions & 0 deletions msgspec/_core.c
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Original file line number Diff line number Diff line change
Expand Up @@ -8342,6 +8342,9 @@ TypedDictInfo_error_missing(TypedDictInfo *self, PyObject *dict, PathNode *path)
}
}
}
// Should be unreachable, but may happen if the TypedDict info
// is inconsistent.
assert(0);
}

static int
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7 changes: 7 additions & 0 deletions msgspec/_utils.py
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Expand Up @@ -227,6 +227,13 @@ def get_typeddict_info(obj):
hints[k] = v.__args__[0]
else:
hints[k] = v

# This can happen if there is a bug in the TypedDict implementation;
# such a bug was present in Python 3.14.
if not all(k in hints for k in required):
raise RuntimeError(
f"Required set {required} contains keys that are no in hints: {hints.keys()}"
)
return hints, required


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18 changes: 18 additions & 0 deletions tests/test_common.py
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Expand Up @@ -2112,6 +2112,24 @@ class Ex(Base, total=False):
dec.decode(proto.encode({"b": "two"}))
assert "Object missing required field `a`" == str(rec.value)

@pytest.mark.parametrize("use_typing_extensions", [False, True])
def test_broken_typeddict(self, proto, use_typing_extensions):
# Check that we don't crash if a TypedDict has incorrect
# introspection data.
if use_typing_extensions:
tex = pytest.importorskip("typing_extensions")
cls = tex.TypedDict
else:
cls = TypedDict

class Ex(cls, total=False):
c: str
Ex.__annotations__ = {"c": "str"}
Ex.__required_keys__ = {"a", "b"}

with pytest.raises(RuntimeError):
proto.Decoder(Ex)

@pytest.mark.parametrize("use_typing_extensions", [False, True])
def test_required_and_notrequired(self, proto, use_typing_extensions):
if use_typing_extensions:
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