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[0.88] Bump Hermes to 260318099.0.4 #1430

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[0.88] Bump Hermes to 260318099.0.4#1430
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Type Pick RequestPick requests to include commits inside a React Native release

Description

@fabriziocucci
fabriziocucci
opened on Sep 26, 2026

Target Branch

0.88

Link to commit or PR to be picked

Hermes release 260318099.0.4, to be cut from 260318099.0.0-stable and pinned into 0.88-stable.

Description

0.88 pins 260318099.0.3 today. One fix and one re-land have landed on the Hermes stable branch beyond the hermes-v260318099.0.3 tag and neither reaches the release until a new tag is cut and RN is bumped to it.

The fix

892dc627d Avoid reserve() in ConsecutiveStringStorage (D121660203, grafts D121478636)

Lazy compilation appends to the string storage every time a newly compiled function adds strings. ConsecutiveStringStorage::appendStorage called reserve() before copying and on libc++ reserve() sizes to exactly the requested capacity rather than growing geometrically, so repeated appends were quadratic. Adds a lazy-string-growth micro-benchmark.

The re-land, which needs a decision before pinning

ace586d90 Back out "Back out D116775223 (VariableScope rescan pick)" (D120733339)

This is not a fix. It is a back-out of a back-out, so its effect is to put a previously reverted change back into the release. The chain:

  • D116775223 landed the original VariableScope rescan pick
  • D118959426 backed it out for a SIGSEGV in AR effects on Messenger Android
  • D120733339 re-lands it

Its stated justification is that the crash could not be reproduced and that another fix may have already covered it. That other fix could not be located on 260318099.0.0-stable or on static_h, so the claim is unverified from the branches alone.

It is also a byte-exact restoration rather than a reworked version. All five touched files (IR.h, IR.cpp, IRBuilder.cpp, Utils.cpp, VariableTest.cpp) match their content at the original pick and differ from hermes-v260318099.0.3.

This was foreseen. #1413 recorded that static_h still carried the change and that it was the source the next stable sync would pull from, so its return was expected rather than accidental.

Also in the cut, no behaviour change

Commit Diff
e3371863e D120562343 Doc comment on IEventLoopControl::scheduleTask
d412d3bd8 D121160587 JSIDynamicTest.cpp, test only
0ad1d016d D121664017 Version bump to .0.4 (facebook/hermes#2197)

The version bump is listed because it is load-bearing rather than incidental. RN Build Static Hermes has no version input: getMainVersion() reads npm/hermes-compiler/package.json verbatim, so the file has to name .0.4 before the workflow can cut it. It read 260318099.0.3 until #2197 landed, which meant a dispatch would have re-cut an already-published version. The stable ref is protected and rejects direct pushes, so the bump had to go through a PR.

Steps

  1. Cut hermes-v260318099.0.4 with release-type=release and update-latest-v1=true. The latest-v1 tag points at .0.3 today and 26xxxx is the newest line, so it should move.
  2. Verify the tag actually contains 892dc627d and ace586d90 before pinning. hermes-v260318099.0.2 was tagged eight hours before a crash fix was backed out and shipped the bad version anyway, so tag contents get checked rather than assumed.
  3. Bump packages/react-native/sdks/hermes-engine/version.properties and packages/react-native/package.json on 0.88-stable. Both read 260318099.0.3 today. Do not hand-commit packages/rn-tester/Podfile.lock; the publish workflow regenerates it.

Prior record

#1413 covers the .0.3 cut and the JSI implementation batch that went into it.

Activity

  1. fabriziocucci
    added
    Type Pick RequestPick requests to include commits inside a React Native release
    on Sep 26, 2026
  2. github-project-automation
    added this to React Native 0.88 Releaseson Sep 26, 2026
  3. github-project-automation
    moved this to Inbox in React Native 0.88 Releaseson Sep 26, 2026

  4. github-actions commented on Sep 26, 2026

    @github-actions
    github-actionsBot
    on Sep 26, 2026 – with GitHub Actions

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  5. fabriziocucci
    added a commit that references this issue on Sep 27, 2026

    Bump Hermes to 260318099.0.4

    993be7d

  6. fabriziocucci commented on Sep 27, 2026

    @fabriziocucci
    fabriziocucci
    on Sep 27, 2026
    CollaboratorAuthor

    Done.

    hermes-v260318099.0.4 was cut from 260318099.0.0-stable (run 36312658384) and is on npm with latest-v1 moved onto it. The tag was verified to contain both fixes before pinning:

    Commit
    892dc627d ConsecutiveStringStorage fix, in the tag
    ace586d90 VariableScope re-land, in the tag

    Pinned into 0.88-stable as 993be7d6c69, bumping both version.properties and package.json from 260318099.0.3 to 260318099.0.4. Podfile.lock was left alone since publish-npm.yml regenerates it.

    Follow-up: facebook/hermes#2211 bumps the Hermes branch to 260318099.0.5 so the next cut does not re-cut .0.4. That step was missed after .0.3 and is what blocked this release.

  7. fabriziocucci
    closed this as completedon Sep 27, 2026
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