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Stale MutationObserver records abort callbacks for active observers

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#58,236 1 comment 0 reactions 0 assignees View on GitHub

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Assessment

Difficulty
3/5
Estimated time
1-2 days
Newbie friendliness
65/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Active
Tech stack
cpp, react-native
Domain
mobile

Research direction

Start by locating the MutationObserver manager and reading its notification pass, then compare it with the equivalent ResizeObserver handling described in the issue. Confirm that a missing registration is ignored and that later active observers in the same native batch still receive their callbacks.

Written by the indexing model from the issue text.

Description

Needs: Author Feedback Needs: Repro
Description

The MutationObserver manager explicitly tolerates stale native records when an observer is disconnected between commit and mount. However, encountering one missing registration returns from the entire notification pass, dropping every later record and callback in the same native batch, including records for still-active observers.

Expected behavior

A stale record for a disconnected observer should be ignored while notification continues for all active observers in the batch, matching the equivalent ResizeObserver handling.

React Native Version

0.87.1 and current main

Affected Platforms

New Architecture - All

Dominant language
C++
Stars
127k
Forks
25.3k
PR merge metrics
No merged PRs in 30d

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

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