trails/openspec/changes/gpx-parser-robustness/tasks.md
Ullrich Schäfer 4536470eb9
feat(gpx): post-parse timestamp repair
Task group 3 of gpx-parser-robustness. Timestamps were passed through raw;
a partially-broken time channel from a flaky recorder silently shrank
moving time and skewed start-time derivation.

New pure `timestamp-repair.ts` applied per segment after parsing:
- validity = Date.parse yields a finite epoch;
- a segment with no valid timestamps is left untouched (untimed track);
- >50% invalid → drop all the segment's timestamps (noise, not signal);
- otherwise → linearly interpolate invalid runs between valid neighbours
  (by point index), leading/trailing runs clamp to the nearest valid
  timestamp; only repaired points are rewritten as ISO 8601, valid points
  keep their original string.

Monotonicity intentionally not enforced (movingTime already skips
non-positive intervals; reordering would be fabrication). No GpxData shape
change. Wired into parseTracks output in parse.ts.

Verified: gpx typecheck + lint clean, 81/81 tests pass, journal + planner
typecheck unchanged.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-07-14 00:10:57 +02:00

2.5 KiB

1. Parser lenience

  • 1.1 Add a finite-number coordinate gate in packages/gpx/src/parse.ts: skip trkpt/rtept with missing or non-finite lat/lon; treat non-finite <ele> as undefined
  • 1.2 Drop segments with fewer than 2 surviving points
  • 1.3 Unit tests: missing-lat point skipped, garbage lat skipped with finite stats, garbage ele → undefined with finite gain/loss, single-point segment dropped, well-formed files byte-identical output to before

2. Route (<rte>) support

  • 2.1 Parse <rte>/rtept as track segments (appended after <trk> segments), reusing the same point parsing and lenience
  • 2.2 Unit tests: route-only file yields one segment and passes validateGpx; mixed trk+rte ordering; rtept with ele/time preserved

3. Timestamp repair

  • 3.1 Create packages/gpx/src/timestamp-repair.ts: per-segment pass — >50% invalid → drop all; else linear interpolation between valid neighbors with leading/trailing clamp; output ISO 8601 strings
  • 3.2 Wire the repair pass into parseTracks output in parse.ts
  • 3.3 Unit tests (timestamp-repair.test.ts): sparse invalid interpolated, >50% invalid dropped (and movingTime returns null), leading/trailing clamp, all-valid untouched, no-timestamps untouched

4. Metadata fallback

  • 4.1 Fall back to first <trk>/<rte> <name>/<desc> when <metadata> lacks them; merge distinct <cmt> into description with blank-line separator, dedup identical
  • 4.2 Unit tests: track-name fallback, metadata precedence, cmt merge, identical cmt deduped

5. Fixture corpus

  • 5.1 Create packages/gpx/fixtures/ with purpose-named files: route-only.gpx, missing-coords.gpx, garbage-ele.gpx, timestamps-partial.gpx, timestamps-mostly-invalid.gpx, multi-track.gpx, unicode-name.gpx, namespaced-extensions.gpx (Garmin/OsmAnd-style extensions)
  • 5.2 Add trimmed real-world exports for supported integrations (Komoot, Wahoo) with any personal data scrubbed
  • 5.3 Extend parse-node.test.ts to load every fixture from disk and assert expected repaired output (a fixture table test so new files are picked up automatically or fail loudly)

6. Verification

  • 6.1 Typecheck + run full gpx package suite; confirm GpxData shape unchanged and journal/planner compile without changes
  • 6.2 Manual check: import a route-only GPX and a partially-broken GPX through the journal import flow; confirm both save with sane stats
  • 6.3 Run pnpm typecheck && pnpm lint && pnpm test and the e2e suites