Crash report
What happened?
The following code causes a crash in cpython:
class Generic:
def __call__(*a):
print(a)
def __getattr__(self, name):
return Generic()
name_5 = Generic()
type name_3[*name_2] = 0
name_3[name_5][0]output:
(<__main__.Generic object at 0x7fb99dc5a280>, name_3[<__main__.Generic object at 0x7fb99d792420>], (0,))
(<__main__.Generic object at 0x7fb99dbd7960>, None)
python3: ./Include/cpython/tupleobject.h:24: PyTuple_GET_SIZE: Assertion `PyTuple_Check(op)' failed.
fish: Job 1, '../cpython/install/bin/python3 …' terminated by signal SIGABRT (Abbruch)
I found this example while fuzzing with pysource-codegen.
CPython versions tested on:
3.12, 3.13, 3.14, 3.15
Operating systems tested on:
Linux
Output from running 'python -VV' on the command line:
Python 3.14.0rc2+ (heads/3.14:45a79b4f4b7, Sep 3 2025, 22:05:34) [GCC 12.2.0]
Linked PRs
Crash report
What happened?
The following code causes a crash in cpython:
output:
I found this example while fuzzing with pysource-codegen.
CPython versions tested on:
3.12, 3.13, 3.14, 3.15
Operating systems tested on:
Linux
Output from running 'python -VV' on the command line:
Python 3.14.0rc2+ (heads/3.14:45a79b4f4b7, Sep 3 2025, 22:05:34) [GCC 12.2.0]
Linked PRs
__typing_subst__returns a tuple #138482__typing_subst__returns a tuple (GH-138482) #138784__typing_subst__returns a tuple (GH-138482) #138786