Unify PYTHONPATH setup for subprocesses

[KRRT7]

Summary

• Extract duplicated PYTHONPATH-prepending boilerplate into make_env_with_project_root() in shell_utils.py
• Replace inline PYTHONPATH setup across 6 call sites with the new helper
• Add missing PYTHONPATH to the CrossHair subprocess.run call and the is_valid_concolic_test subprocess

[claude]

PR Review Summary

Prek Checks

✅ All checks passed — ruff check and ruff format both clean. No fixes needed.

Mypy

✅ No new mypy errors introduced by this PR. All 157 errors in the changed files are pre-existing (e.g., get_cross_platform_subprocess_run_args return type mismatch, self.args being Namespace | None).

Code Review

✅ No critical issues found. This is a clean refactoring that extracts the repeated PYTHONPATH setup pattern (5 call sites across 5 files) into a single make_env_with_project_root() helper in shell_utils.py.

Changes verified:

• make_env_with_project_root correctly prepends project_root to PYTHONPATH (matching the prior inline logic)
• All 5 call sites correctly replaced with the new helper
• Unused os imports properly removed from tracer.py and concolic_testing.py
• No behavioral changes, no new dependencies, no API breakage

Test Coverage

File	Main	PR	Delta
codeflash/benchmarking/trace_benchmarks.py	50%	46%	-4%
codeflash/code_utils/concolic_utils.py	88%	88%	0%
codeflash/code_utils/shell_utils.py	59%	61%	+2%
codeflash/optimization/function_optimizer.py	18%	18%	0%
codeflash/tracer.py	—	—	—
codeflash/verification/concolic_testing.py	30%	32%	+2%
Overall	78.54%	78.58%	+0.04%

• trace_benchmarks.py -4% is from statement count change (30→26 stmts) altering the ratio, not from uncovered new code.
• shell_utils.py +2% reflects the new make_env_with_project_root being exercised via tests that call is_valid_concolic_test.
• ✅ No coverage regression overall.
• tracer.py excluded from report by coverage (not imported during tests).

Note: 8 pre-existing test failures in tests/test_tracer.py (same on main and PR branch).

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Last updated: 2026-02-13