Concurrent edits to shared notes (e.g., one user checks a shopping list
item while another adds an item) were lost because the sync system used
whole-document Last-Write-Wins. This replaces it with a 3-way line-level
content merge using node-diff3, so changes to different lines are
preserved from both users.
Key changes:
- Add node-diff3 for 3-way line-level content merging
- Remove the timestamp gate in processSyncPush that rejected entire
offline sync pushes when another user had updated the note
- Add content merge to both the sync push path and the PATCH endpoint,
using version snapshots as the merge base
- Send baseVersion from the client so the server can find the correct
common ancestor for 3-way merge
- Protect pending local fields during client pull merge by reading
the sync queue and preserving queued-but-unpushed changes
- Add comprehensive tests for content merge, server sync, and CRDT merge
https://claude.ai/code/session_01FNpVBBjM6vKzfR8y9NM9Ci
Claude