Fix a crash when nonlocal is defined at module level

[mbyrnepr2]

Type of Changes

	Type
✓	🐛 Bug fix
	✨ New feature
	🔨 Refactoring
	📜 Docs

Description

Defining nonlocal at the module level is a SyntaxError.

Closes #8735

[jacobtylerwalls]

Thanks for picking this up! When I apply the crash fix, but without applying the new checker, I get this from linting the bug report:

a.py:1:0: E0117: nonlocal name X found without binding (nonlocal-without-binding)

Is that enough, without needing a new checker?

[mbyrnepr2]

Yeah we could also do that @jacobtylerwalls. My rationale is that the new checker correspond to a different Python output when running the code. But I understand if we want to keep things lean and just stick to the fix without the new checker.

[jacobtylerwalls]

Just checked, and when doing this:

class A:
     nonlocal X

python still gives a SyntaxError, like so:

SyntaxError: no binding for nonlocal 'X' found

So I think we can just let the original message do the work.

[mbyrnepr2]

The rationale for the new checker was to distinguish the module-level definition from the function/class definition. Python gives different messages for these 2 distinct situations and I tried to reflect that here.

That said, we don’t necessarily need to mirror the Python messages if Pylint output is accurate enough.

[jacobtylerwalls]

Ah, I didn't realize you were targeting the different wording in the two SyntaxErrors. (But yes, I think that's too subtle to justify adding a new check.)

[github-actions]

🤖 According to the primer, this change has no effect on the checked open source code. 🤖🎉

This comment was generated for commit 82c31e5

[codecov]

Codecov Report

Merging #8737 (82c31e5) into main (59194eb) will not change coverage.
The diff coverage is 100.00%.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #8737   +/-   ##
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  Coverage   95.82%   95.82%           
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  Files         173      173           
  Lines       18381    18381           
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  Hits        17613    17613           
  Misses        768      768           

Impacted Files	Coverage Δ
pylint/checkers/variables.py	97.24% <100.00%> (ø)