react / react/react-native

Reentrant structuredClone breaks outer circular references

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Dominant language
C++
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Description

Description

The React Native structuredClone polyfill reuses one module-global memory map under the assumption that cloning does not invoke user code. Enumerable property getters do execute, however, and can call structuredClone recursively. The inner call's finally clears the outer clone's memory, so later circular references are cloned again instead of pointing to the outer result.

Expected behavior

Each reentrant clone should have independent cycle-detection memory, while ordinary non-reentrant calls may retain the existing reusable-map optimization.

React Native Version

0.87.1 and current main

Affected Platforms

JavaScript runtime - 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 React Native structuredClone polyfill and its cycle-detection memory handling. Reproduce a nested clone from an enumerable getter with an outer circular reference, then verify that reentrant calls use independent memory while ordinary cloning retains its behavior.

Written by the indexing model from the issue text.

Assessment

Tech stack
javascript, react-native
Domain
mobile
Issue type
Bug
Difficulty
3/5
Estimated time
1-2 days
Activity status
Active
Clarity
Mostly clear
Newbie friendliness
62/100

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