fix: handle for-loop variable shadowing correctly

[emmanuel-ferdman]

Type of Changes

	Type
✓	🐛 Bug fix

Description

Pylint incorrectly reported undefined-variable (E0602) for code like:

item = (1, 2, 3)
for item in item:  # E0602: Undefined variable 'item'
  print(item)

The problem is that in get_next_to_consume(), the for-loop detection logic always set found_nodes = None even when detecting for X in X: patterns, which eventually triggers the fallback undefined-variable error. The solution updates the logic to distinguish between two cases:

• Variable reuse: item = 1; for item in item: - In this case, keep original definition.
• Undefined reference: for iteree in iteree: - In this case, trigger error.

Closes #10562

[Pierre-Sassoulas]

Thank you for opening this PR :)

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 95.90%. Comparing base (5b39db3) to head (fd8fc82).
⚠️ Report is 64 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #10569   +/-   ##
=======================================
  Coverage   95.90%   95.90%           
=======================================
  Files         176      176           
  Lines       19453    19456    +3     
=======================================
+ Hits        18656    18659    +3     
  Misses        797      797           

Files with missing lines	Coverage Δ
pylint/checkers/variables.py	97.41% <100.00%> (+<0.01%)	⬆️

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[Pierre-Sassoulas]

Great ! Let's rename doc/whatsnew/fragments/10562.bugfix.rst to doc/whatsnew/fragments/10562.bugfix and merge this :)

[github-actions]

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

This comment was generated for commit fd8fc82