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🐛 Stop stale remote presence catch-up looping forever - #745
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coverage: 97.854% (+0.003%) from 97.851% — fix/issue-732-presence-catch-up-loop into main |
alecgibson
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Oct 8, 2026
Fixes #732 At the moment, `RemoteDocPresence` ignores errors returned by `ot.transformPresence()` when catching up stale presence. Since `presence.v` isn't advanced on error, the loop never ends: 1. A peer sends a stale presence with `t: null` and no `d` 2. An op is submitted to the doc 3. The peer resends the stale presence 4. The receiving client hangs, freezing the tab This change drops the pending presence and emits the error instead, as we already do in `_transformAgainstOp()`. `ot.transformPresence()` also now returns a `ShareDBError` like the rest of `ot`, since that's what the presence `'error'` event is documented to emit. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com>
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🟢 Approval recommended
The fix terminates the failing catch-up path and includes focused regression coverage.
0 open findings
What changed in this PR
Prevents infinite stale-presence catch-up loops by handling transformation failures safely.
Changes:
- Drops untransformable pending presence and stops operation caching.
- Returns
ShareDBErrorinstances from presence transformations. - Adds regression coverage for recovery after malformed presence.
| File | Description |
|---|---|
lib/client/presence/remote-doc-presence.js |
Handles catch-up transformation errors. |
lib/ot.js |
Standardizes transformation errors. |
test/client/presence/doc-presence.js |
Tests error emission and recovery. |
🧠 Review effort: Balanced
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alecgibson
marked this pull request as ready for review
October 8, 2026 13:57
dawidreedsy
approved these changes
Oct 8, 2026
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Fixes #732
At the moment,
RemoteDocPresenceignores errors returned byot.transformPresence()when catching up stale presence. Sincepresence.visn't advanced on error, the loop never ends:t: nulland nodThis change drops the pending presence and emits the error instead, as we already do in
_transformAgainstOp().ot.transformPresence()also now returns aShareDBErrorlike the rest ofot, since that's what the presence'error'event is documented to emit.🤖 Generated with Claude Code
Co-Authored-By: Claude noreply@anthropic.com