johnslavik · GitHub

Crash report

What happened?

Minimal repro:

print("Reproducing!")
exec("", closure=object())

Fails with

Reproducing!
python: Python/ast.c:1047: _PyAST_Validate: Assertion `!PyErr_Occurred()' failed.
Aborted (core dumped)

Note the error occurs not because the passed closure= is incorrect (it should be a tuple of cell objects), but because closure= is not allowed when string is the source.

The reason for that to happen is a missing goto error jump:

if (closure != NULL) {
PyErr_SetString(PyExc_TypeError,
"closure can only be used when source is a code object");
}

causing the rest of the code to execute and reach _PyAST_Validate.

In the PR, I included the missing test case.

CPython versions tested on:

CPython main branch

Operating systems tested on:

Linux

Output from running 'python -VV' on the command line:

Python 3.14.0a5+ (heads/main-dirty:f9a7d41bacb, Feb 13 2025, 04:52:15) [GCC 11.4.0]

Linked PRs

Read the original on github.com ↗