GAP-43: master_data_routes._save_master bypasses post-write schema validation

[warnes]

Summary

master_data_routes.py:38–51 (_save_master) creates a backup and writes without running validate_master_data_file. The web_app.py version of the same helper does run validation and restores the backup on failure. Malformed writes through the routes module bypass the safety net.

Evidence

master_data_routes.py:38–51 — _save_master backs up and writes without validation.

web_app.py:1166–1191 — _save_master runs validate_master_data_file after writing, restores backup on failure.

Two implementations of the same write-path helper with different safety guarantees.

Impact

Writes routed through master_data_routes._save_master can corrupt Master_CV_Data.json without triggering the automatic backup-restore. This is a data integrity risk.

Acceptance criteria

• A single _save_master implementation that always runs post-write validation with backup-restore on failure
• All write routes use the validated version
• The inconsistency between modules is resolved

Related

• GAP-43 in tasks/gaps.md
• Affected persona stories: US-M1