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gh-132002: Fix crash of ContextVar on unhashable str subtype #132003

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Merged
merged 2 commits into from
Apr 2, 2025
Merged

gh-132002: Fix crash of ContextVar on unhashable str subtype #132003

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37ae65a
gh-132002: Fix crash of `ContextVar` on unhashable `str` subtype
sobolevn Apr 2, 2025
58f539d
Address review
sobolevn Apr 2, 2025
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9 changes: 9 additions & 0 deletions Lib/test/test_context.py
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Original file line number Diff line number Diff line change
Expand Up @@ -92,6 +92,15 @@ def test_context_new_1(self):
contextvars.Context(a=1)
contextvars.Context(**{})

def test_context_new_unhashable_str_subclass(self):
# gh-132002: it used to crash on unhashable str subtypes.
class weird_str(str):
def __eq__(self, other):
pass

with self.assertRaisesRegex(TypeError, 'unhashable type'):
contextvars.ContextVar(weird_str())

def test_context_typerrors_1(self):
ctx = contextvars.Context()

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2 changes: 2 additions & 0 deletions Misc/NEWS.d/next/Library/2025-04-02-11-31-15.gh-issue-132002.TMsYvE.rst
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Original file line number Diff line number Diff line change
@@ -0,0 +1,2 @@
Fix crash when deallocating :class:`contextvars.ContextVar` with weird
unahashable string names.
13 changes: 6 additions & 7 deletions Python/context.c
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Original file line number Diff line number Diff line change
Expand Up @@ -878,14 +878,7 @@ contextvar_new(PyObject *name, PyObject *def)
return NULL;
}

var->var_hash = contextvar_generate_hash(var, name);
if (var->var_hash == -1) {
Py_DECREF(var);
return NULL;
}

var->var_name = Py_NewRef(name);

var->var_default = Py_XNewRef(def);

#ifndef Py_GIL_DISABLED
Expand All @@ -894,6 +887,12 @@ contextvar_new(PyObject *name, PyObject *def)
var->var_cached_tsver = 0;
#endif

var->var_hash = contextvar_generate_hash(var, name);
if (var->var_hash == -1) {
Py_DECREF(var);
return NULL;
}

if (_PyObject_GC_MAY_BE_TRACKED(name) ||
(def != NULL && _PyObject_GC_MAY_BE_TRACKED(def)))
{
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