# 09. Dead code and obsolete paths check

meta:
  id: pygienium-09
  feature: pygienium
  priority: P2
  depends_on: [pygienium-06]
  tags: [check]

objective:

- Implement the dead-code / obsolete-paths check: find unreferenced exports, dead files, obsolete compatibility shims, migration paths, and unused config; remove them (engineering rule: no backward-compat layers).

deliverables:

- `src/checks/dead-code.ts`: `CheckDefinition` with scan + fix tasks
- Rubric: unreferenced functions/exports, files with zero importers (cross-checked against the review graph), deprecated/compat shims, migration helpers, unused dependencies
- `/pygienium-dead-code` runs E2E

steps:

- Author `buildScanTask`: agent uses grep/import-graph + recon candidates to list dead code, writes `pygienium/checks/dead-code/findings.md` categorized by type
- Author `buildFixTask`: remove clearly-dead items; list ambiguous ones (dynamic imports, runtime registration) for human review per pi-lens suspected-dead-weight semantics
- Register the check

tests:

- Integration: add an unused exported function + an obsolete compat wrapper; run `--fix`; assert both removed and changes.md lists them; assert a dynamically-imported shim is NOT auto-removed

acceptance_criteria:

- findings.md categorizes dead code by type (export, file, shim, dep)
- `--fix` removes clearly-dead items and preserves dynamic/runtime-registered ones with a review flag

validation:

- Inspect `pygienium/checks/dead-code/{findings.md,changes.md}`

notes:

- Cross-reference the project_report "suspected dead weight" semantics — single-importer/zero-importer files
- Engineering rule mandates removing obsolete paths rather than leaving compat shims