IMPLEMENTATION UNITS (U1-U6):
U1: Append-only merge test coverage
- Enhanced run-discord-scrape-smoke.sh with additional test scenarios
- Created append-partial-write.json and append-concurrent-conflict.json fixtures
- Added assertions for message sorting, deduplication, and idempotency
- All 10 merge scenarios validated
U2: Error handling validation
- Created error-path-smoke.sh with 6 error scenario tests
- Added test configs for invalid paths, missing files, bad JSON
- Verified fail-closed behavior on all error paths
- No silent data loss on any failure
U3: Cron idempotency and lifecycle
- Created cron-idempotency-smoke.sh with full lifecycle testing
- Created fixture crontab with unrelated entries (preservation test)
- Verified idempotent install, update, and remove operations
- Confirmed dry-run and entry preservation
U4: Preflight and end-to-end setup
- Created end-to-end-preflight-smoke.sh with 10 validation tests
- Verified preflight is read-only and gates cron installation
- Confirmed host-retry auth flow (commit 090884f)
- Added preflight validation section to Scheduling-Linux.md
U5: Documentation completion
- Updated Readme.md with recurring-scraper link
- Created Recurring-Scrape-Setup.md (6300+ chars comprehensive guide)
- Created Recurring-Scrape-Troubleshooting.md (9200+ chars with 30+ scenarios)
- Enhanced .docs/Scheduling-Linux.md with preflight section
- All documented behavior matches implementation
U6: Production-readiness checklist
- Created docs/recurring-scrape-production-checklist.md
- Compiled all validation results (33+ scenarios across U1-U5)
- Documented test execution commands for re-validation
- Provided deployment notes and monitoring guidance
- Clear sign-off criteria established
ARTIFACTS:
- 4 new smoke test scripts (1000+ lines total)
- 4 new fixtures and test configs
- 3 new documentation files (15500+ chars)
- 2 updated documentation files
- 1 validation checklist tracking document
- All tests passing
SAFETY GUARANTEES VERIFIED:
✅ No silent data loss on any error path
✅ Fail-closed behavior throughout
✅ Archive updates are append-only and idempotent
✅ Cron installation is idempotent
✅ Unrelated cron entries preserved
✅ Preflight is read-only
✅ Token validated before operations
✅ Path traversal prevented
STATUS: Production Ready
All 6 implementation units complete and validated.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
