exec(<string>, closure=<non-None>) failed assertion

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:

cpython/Python/bltinmodule.c

Lines 1175 to 1178 in 2a0256f

    
           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

Unable to reproduce in 3.13 or main branch build with the supplied code:

Reproducing!
Traceback (most recent call last):
  File "<python-input-0>", line 2, in <module>
    exec("", closure=object())
    ~~~~^^^^^^^^^^^^^^^^^^^^^^
TypeError: closure can only be used when source is a code object

Oh! This isn't a segfault. It says "aborted".

@tomasr8

@tomasr8 Should the label be changed to type-bug? It's not a hard crash, just a subtle bug, even though a core dump is produced.

It crashes in debug builds.

gh-130070: Fix `exec(<string>, closure=<non-None>)` unexpected path (#…

pythongh-130070: Fix `exec(<string>, closure=<non-None>)` unexpected …

[3.13] gh-130070: Fix `exec(<string>, closure=<non-None>)` unexpected…

Thank you Bartosz!

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`exec(<string>, closure=<non-None>)` failed assertion #130070

Crash report

What happened?

CPython versions tested on:

Operating systems tested on:

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

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

exec(<string>, closure=<non-None>) failed assertion #130070

Description

Crash report

What happened?

CPython versions tested on:

Operating systems tested on:

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

Linked PRs

Activity

StanFromIreland commented on Feb 13, 2025

johnslavik commented on Feb 13, 2025

johnslavik commented on Feb 13, 2025

encukou commented on Feb 13, 2025

Eclips4 commented on Apr 17, 2025

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`exec(<string>, closure=<non-None>)` failed assertion #130070