Four related issues made uploading 271+ activities unreliable:
1. merge_all/write_combined_feed were inside the extraction try/except —
any merge race returned 422 even though the file was on disk, causing
the mobile app to permanently mark the upload as failed. Fixed by
moving them to a separate best-effort try/except after the extraction
block. Switch to merge_one (single-activity symlink) instead of
merge_all (full rebuild) so each upload is O(1) FS ops, not O(N).
2. The dev watcher fired merge_all for every activity .json write AND the
upload endpoint also ran merge_all — O(N²) symlink operations during
bulk uploads. Watcher now skips activities/*.json changes (upload
endpoint handles those directly).
3. Vite/Chokidar followed the public/data symlink and opened a handle per
activity file; constant merge rebuilds exhausted file descriptors and
crashed the Astro dev server. Fixed with watch.ignored on public/data.
4. _write_year_shards and write_combined_feed used f.unlink() without
missing_ok=True — concurrent callers racing the same file threw
FileNotFoundError which propagated as a false extraction failure.
Davide Scaini
be772bd3df