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[3.12] gh-128632: fix segfault on nested __classdict__ type param (GH… (#132090)

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(cherry picked from commit 891c61c1fa)

Co-authored-by: Tomasz Pytel <tompytel@gmail.com>
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Tomasz Pytel 2025-04-04 11:48:57 -04:00 • committed by GitHub
parent 05213afaa7
commit 3d3e7b0ada
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3 changed files with 45 additions and 0 deletions
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19
Lib/test/test_syntax.py
View file

@ -2244,6 +2244,25 @@ if x:
self.assertRaises(IndentationError, exec, code)
@support.cpython_only
def test_disallowed_type_param_names(self):
# See gh-128632
self._check_error(f"class A[__classdict__]: pass",
f"reserved name '__classdict__' cannot be used for type parameter")
self._check_error(f"def f[__classdict__](): pass",
f"reserved name '__classdict__' cannot be used for type parameter")
self._check_error(f"type T[__classdict__] = tuple[__classdict__]",
f"reserved name '__classdict__' cannot be used for type parameter")
# These compilations are here to make sure __class__, __classcell__ and __classdictcell__
# don't break in the future like __classdict__ did in this case.
for name in ('__class__', '__classcell__', '__classdictcell__'):
compile(f"""
class A:
class B[{name}]: pass
""", "<testcase>", mode="exec")
@support.cpython_only
def test_nested_named_except_blocks(self):
code = ""

2
Misc/NEWS.d/next/Core_and_Builtins/2025-01-11-20-11-28.gh-issue-128632.ryhnKs.rst Normal file
View file

@ -0,0 +1,2 @@
Disallow ``__classdict__`` as the name of a type parameter. Using this
name would previously crash the interpreter in some circumstances.

24
Python/symtable.c
View file

@ -2191,6 +2191,24 @@ symtable_visit_expr(struct symtable *st, expr_ty e)
VISIT_QUIT(st, 1);
}
static int
symtable_visit_type_param_check_reserved_name(struct symtable *st, type_param_ty tp, identifier name)
{
if (_PyUnicode_Equal(name, &_Py_ID(__classdict__))) {
PyObject *error_msg = PyUnicode_FromFormat("reserved name '%U' cannot be "
"used for type parameter", name);
PyErr_SetObject(PyExc_SyntaxError, error_msg);
Py_DECREF(error_msg);
PyErr_RangedSyntaxLocationObject(st->st_filename,
tp->lineno,
tp->col_offset + 1,
tp->end_lineno,
tp->end_col_offset + 1);
return 0;
}
return 1;
}
static int
symtable_visit_type_param(struct symtable *st, type_param_ty tp)
{
@ -2201,6 +2219,8 @@ symtable_visit_type_param(struct symtable *st, type_param_ty tp)
}
switch(tp->kind) {
case TypeVar_kind:
if (!symtable_visit_type_param_check_reserved_name(st, tp, tp->v.TypeVar.name))
VISIT_QUIT(st, 0);
if (!symtable_add_def(st, tp->v.TypeVar.name, DEF_TYPE_PARAM | DEF_LOCAL, LOCATION(tp)))
VISIT_QUIT(st, 0);
if (tp->v.TypeVar.bound) {
@ -2219,10 +2239,14 @@ symtable_visit_type_param(struct symtable *st, type_param_ty tp)
}
break;
case TypeVarTuple_kind:
if (!symtable_visit_type_param_check_reserved_name(st, tp, tp->v.TypeVarTuple.name))
VISIT_QUIT(st, 0);
if (!symtable_add_def(st, tp->v.TypeVarTuple.name, DEF_TYPE_PARAM | DEF_LOCAL, LOCATION(tp)))
VISIT_QUIT(st, 0);
break;
case ParamSpec_kind:
if (!symtable_visit_type_param_check_reserved_name(st, tp, tp->v.ParamSpec.name))
VISIT_QUIT(st, 0);
if (!symtable_add_def(st, tp->v.ParamSpec.name, DEF_TYPE_PARAM | DEF_LOCAL, LOCATION(tp)))
VISIT_QUIT(st, 0);
break;