⚡ Bolt: avoid eager list materialization in AST traversals

[tachyon-beep]

💡 What: Updated recursive AST traversals in _assignment_callee and _collect_return_paths to accept Iterable[ast.AST] and pass ast.iter_child_nodes() directly instead of eagerly materializing it into lists using list().

🎯 Why: Calling list(ast.iter_child_nodes()) allocates a new list in memory at every level of recursive AST descent. Since Python ASTs can be quite deep and numerous across a large project, passing the underlying generator directly prevents unnecessary memory allocations and garbage collector pressure.

📊 Impact: Reduces intermediate object allocations for AST branches during recursive tree walks. Faster, lower-memory taint analysis.

🔬 Measurement: Verifiable via memory profiling on large ASTs or running standard pytest benchmarks (performance parity check). Tests run fully cleanly after this adjustment.

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PR created automatically by Jules for task 1881551180393145932 started by @tachyon-beep

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[Copilot]

Pull request overview

This PR reduces memory allocations during recursive Python AST traversals in the taint scanner by avoiding repeated list(ast.iter_child_nodes(...)) materialization and instead passing the child-node iterator through the recursion.

Changes:

• Updated _assignment_callee and _collect_return_paths to accept Iterable[ast.AST] and recurse using ast.iter_child_nodes(node) directly.
• Added a Bolt note documenting the “avoid eager AST child list materialization” performance guideline.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
src/wardline/scanner/taint/variable_level.py	Switches recursive AST traversal helpers to take Iterable and passes ast.iter_child_nodes() directly to reduce per-level allocations.
.jules/bolt.md	Documents the AST traversal performance guideline that motivates the change.

Suppressed comments (1)

src/wardline/scanner/taint/variable_level.py:2512

• The new _assignment_callee(...) call is inlined onto one long line, while nearby calls in this module use multi-line formatting. Reformatting this call improves readability and avoids potential line-length/lint issues without reintroducing eager list materialization.

        # ⚡ Bolt: pass generator directly instead of list(ast.iter_child_nodes()) to avoid memory allocations
        nested = _assignment_callee(ast.iter_child_nodes(node), name, worst, function_taint, taint_map, var_taints)

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