[Flight] Allow cyclic references to be serialized when unwrapping lazy elements

[everettbu]

Mirror of facebook/react#35471
Original author: unstubbable

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When renderModelDestructive unwraps a lazy element and subsequently calls renderModelDestructive again with the resolved model, we should preserve the parent connection so that cyclic references can be serialized properly. This can occur in an advanced scenario where the result from the Flight Client is serialized again with the Flight Server, e.g. for slicing a precomputed payload into multiple parts.

Note: The added test only fails when run with --prod. In dev mode, the component info outlining prevents the issue from occurring.

[greptile-apps]

Greptile Overview

Greptile Summary

Fixed cyclic reference serialization when unwrapping lazy elements by preserving the parent connection.

• Changed renderModelDestructive call in REACT_LAZY_TYPE case to pass parent and parentPropertyName instead of emptyRoot and empty string
• This enables the writtenObjects WeakMap to properly track object references through the parent chain for cycle detection
• Added comprehensive test that verifies cyclic objects survive two rounds of Flight serialization/deserialization
• The fix specifically addresses an advanced scenario where Flight Client results are re-serialized with Flight Server (e.g., for payload slicing)

Confidence Score: 5/5

• This PR is safe to merge with no issues found
• The change is minimal, targeted, and logically correct - it preserves the parent chain needed for cycle detection when unwrapping lazy elements. The implementation aligns with how other parts of the codebase handle object tracking via writtenObjects. The test thoroughly validates the fix by testing the exact failure scenario (cyclic references through two serialization rounds).
• No files require special attention

Important Files Changed

File Analysis

Filename	Score	Overview
packages/react-server/src/ReactFlightServer.js	5/5	Correctly preserves parent chain when unwrapping lazy elements to enable cyclic reference serialization
packages/react-server-dom-webpack/src/tests/ReactFlightDOMEdge-test.js	5/5	Comprehensive test verifying cyclic references survive two rounds of serialization/deserialization

[everettbu]

Upstream PR was closed or merged. Code is synced via branch mirror.