[DG-Elom]

Fixes #175

B007 reported a loop control variable as unused when its only readers were a function or lambda defined in the same scope as the loop:

def main():
    def f(x):
        print(i, x)

    for i in [1, 2, 3]:
        f("HI")

The variable now counts as used when a function defined in that scope reads it. Scopes are resolved with the standard library symtable, so shadowing (a parameter or local of the same name), nonlocal, global and class scopes follow CPython: free variables of the nested functions, or, for a loop at module level, the globals they read. symtable is only run when a loop has an unused control variable, once per file; if the source can't be compiled, no exemption is applied.

Tests are in tests/eval_files/b007.py, b007_module_scope.py and b007_py310.py (the issue example, functions defined before/after the loop, shadowing, global/nonlocal, classes, decorators, match). Running B007 over the CPython 3.13 stdlib and a site-packages tree (5,427 files), the only change is 7 fewer reports, each a loop variable read by a closure (e.g. Lib/test/test_range.py, Lib/test/pickletester.py); none are added. README changelog updated.

[Copilot]

🟡 Changes recommended

Unresolved moderate issues affect scope correctness and analysis reliability.

1 open finding

• Global loop variables are incorrectly flagged despite nested reads · New

What changed in this PR

Updates B007 to recognize loop-variable reads from nested functions and lambdas using symtable.

Changes:

• Adds closure-aware and module-scope analysis.
• Adds regression tests for scope, shadowing, and pattern matching.
• Updates the changelog.

Unresolved issues remain around global and intermediate-scope bindings, nonlocal stores, repeated symbol-table scans, and source normalization.

File	Description
tests/​eval_files/​b007.py	Tests closure and shadowing scenarios.
tests/​eval_files/​b007_py310.py	Tests pattern-matching cases.
tests/​eval_files/​b007_module_scope.py	Tests module-level resolution.
README.rst	Documents the B007 change.
bugbear.py	Implements symbol-table-based closure detection.

🧠 Review effort: Lite

---

💡 Add a code-review agent skill or configure MCP servers for context-aware, tailored reviews. Learn more in the docs.

[cooperlees]

Let's fix the found globals effect please ...

[cooperlees]

Fixed the Copilot finding: when the enclosing scope declares the loop variable global, nested functions that read it have no free variable, so _closure_reads now also counts referenced globals when the name is global in the enclosing symtable table.

Details:

• Direct reads (global i + def g(): return i) and deeply-nested reads are exempt.
• Shadowing still flags B007: names bound locally in an intermediate function (free, not global in the reading table) or by a comprehension, and store-only global writes (is_referenced() == False).
• nonlocal in the enclosing scope was already handled via free variables (verified with symtable).
• Added 4 regression cases to tests/eval_files/b007.py.
• Rebased onto current main (fixed README.rst changelog conflict; full suite: 128 passed, 2 skipped).

[cooperlees]

Globals fix verified: enclosing-scope global reads (direct and deeply nested) are now exempt, while intermediate-local shadowing, comprehension shadowing, and store-only writes still flag. Rebased onto main, CI + pre-commit green.