react / react/react-native

Stale MutationObserver records abort callbacks for active observers

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Dominant language
C++
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Avg merge
1d 23h
Merged PRs (30d)
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Description

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

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.

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.

Assessment

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

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