Unobserve removed Fragment children by OskarEichler · Pull Request #37452 · react/react

OskarEichler · 2026-08-30T07:24:06Z

Summary

Unobserve removed Fragment element children from every registered observer.
Mirror the existing insertion behavior while continuing to skip text children.
Strengthen the dynamic-child regression with the exact removed node assertion.

Breaking changes

None. Fragment refs remain experimental/gated; this completes expected observer cleanup.

Verification

Full ReactDOMFragmentRefs suites: 90 tests passed.
DOM-node Flow, targeted ESLint, Prettier, and git diff --check passed.

Fixes #37451

github-actions · 2026-08-30T07:24:22Z

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) Fragment IntersectionObserver targets used to stay observed after a child was removed so the exit record (isIntersecting: false) could still fire, but that left the observer holding detached nodes. We now unobserve ResizeObserver targets immediately, and delay IntersectionObserver unobserve until after paint so the exit still lands, then drop the strong ref. If the same node is reinserted before that flush, we cancel the pending unobserve so a later cleanup does not detach a child that’s still visible. Closes #37452 Closes #37302 Fixes #37451

) Fragment IntersectionObserver targets used to stay observed after a child was removed so the exit record (isIntersecting: false) could still fire, but that left the observer holding detached nodes. We now unobserve ResizeObserver targets immediately, and delay IntersectionObserver unobserve until after paint so the exit still lands, then drop the strong ref. If the same node is reinserted before that flush, we cancel the pending unobserve so a later cleanup does not detach a child that’s still visible. Closes #37452 Closes #37302 Fixes #37451 DiffTrain build for [065bc84](065bc84)

…ct#37408) Fragment IntersectionObserver targets used to stay observed after a child was removed so the exit record (isIntersecting: false) could still fire, but that left the observer holding detached nodes. We now unobserve ResizeObserver targets immediately, and delay IntersectionObserver unobserve until after paint so the exit still lands, then drop the strong ref. If the same node is reinserted before that flush, we cancel the pending unobserve so a later cleanup does not detach a child that’s still visible. Closes react#37452 Closes react#37302 Fixes react#37451 DiffTrain build for [065bc84](react@065bc84)

Unobserve removed Fragment children

bc41a79

meta-cla Bot added the CLA Signed label Aug 30, 2026

eps1lon mentioned this pull request Aug 31, 2026

[DOM] Unobserve fragment IntersectionObserver targets after exit #37408

Merged

jackpope closed this in #37408 Aug 31, 2026

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Unobserve removed Fragment children - #37452

Unobserve removed Fragment children#37452
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OskarEichler:fix/react-dom-unobserve-removed-fragment-children

OskarEichler commented Aug 30, 2026

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