fix(desktop): recover from a stale IME composition flag that silently blocks all sends

[AIalliAI]

Summary

Defensive fix for #44135 — Desktop composer Enter (and the Send button) silently doing nothing, with no error and no session.create / prompt.submit ever reaching the gateway.

The composer guards submission behind composingRef (set on compositionstart, cleared on compositionend) so that Enter confirming a CJK IME preedit doesn't split the message (#37483 class). But if compositionend is ever missed — focus jump, input-source switch, or a programmatic DOM mutation aborting the preedit — the flag wedges true and from then on every path out of the composer is silently swallowed:

• handleEditorKeyDown returns before the Enter branch (composer/index.tsx)
• the form onSubmit guard blocks the Send button too

No error surfaces, nothing hits the gateway, and the state persists until the composer instance remounts. For Chinese IME users even ASCII typing runs through composition (Pinyin ABC mode), so one wedge kills all sending — matching the reporter's "first new sessions, then everything" progression (pre-decoupling, composer instances differed per thread and degraded one by one as each was touched).

Fix

Two recovery points, each grounded in an invariant Chromium (Electron's only engine) guarantees:

1. keydown self-heal — every keydown during a genuine composition carries nativeEvent.isComposing === true. If the ref says composing but the native flag says no, the ref is stale: clear it before the guard reads it.
2. blur reset — a composition cannot survive focus loss (Chromium commits the preedit and fires compositionend on blur). Clear the flag unconditionally on blur; this is what un-wedges the Send button path, which has no native composition flag to consult.

Genuine IME protection is unchanged: Enter with isComposing=true is still swallowed, and the new test locks that in alongside the recovery behavior.

Testing

• New enter-stale-ime-flag.test.tsx (harness-mirror style, same as enter-submit-dom-race.test.tsx): wedged-flag Enter recovery, genuine-composition swallow + post-compositionend send, Send-button unblock after blur with a missed compositionend.
• npx vitest run --environment jsdom src/app/chat/composer/ — 7 files, 25 tests pass.
• tsc -b and eslint clean on touched files.

Note for the reporter's setup: the bootstrap install.sh HTTP 404s in their log are a separate, expected fallback path (locally-built app stamped to an unpushed commit; bootstrap-runner.cjs falls back to the installed checkout's script) and are not related to this bug.

Fixes #44135

[liuhao1024]

✅ Verification — stale IME composition flag recovery is well-designed

Checked:

• The self-heal logic (composingRef.current && !event.nativeEvent.isComposing) correctly trusts Chromium's per-keydown isComposing flag to recover from a missed compositionend
• The blur handler unconditionally clears composingRef.current — safe because a composition never survives focus loss in any browser
• The form onSubmit guard (composingRef.current ? return : submitDraft()) is preserved and still works correctly with the new self-heal
• Test coverage is thorough: covers genuine composition (Enter swallowed), wedge recovery (Enter sends after stale flag), and blur recovery (Send button works after missed compositionend)

The approach is defensive without being over-eager — it only clears the flag when the native event explicitly says composition is not active. LGTM.

[tonydwb]

Code Review: PR #44149

Verdict: Approved — well-reasoned defensive fix for stale IME composition flag.

Summary

Files changed: apps/desktop/src/app/chat/composer/index.tsx (+17, -1), new test file (+129)

Adds recovery from a stale composingRef that silently blocks Enter and Send button when compositionend is missed (focus jumps, input-source switches, DOM mutations).

Assessment

Correctness: Two recovery points grounded in Chromium invariants: (1) keydown self-heal clears the flag when native isComposing says we're not composing; (2) blur unconditionally clears the flag. Both are safe — genuine IME composition is still protected.

No issues found.

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Reviewed by Hermes Agent

[AIalliAI]

Requesting maintainer review — this is ready to land from my side. Standalone fork CI is pending first-run approval here; the rollup branch in #44061 carrying this session's batch is fully green on upstream CI (all test shards, typecheck, e2e).

[teknium1]

Thanks for the focused regression fix. The underlying defect remains on current main: apps/desktop/src/app/chat/composer/index.tsx:370 returns for a stale composingRef, :726 does not reset that ref on blur, and the form submit guard at :830 blocks Send as well.

The proposed keydown recovery and blur reset directly cover those paths while preserving the genuine-composition guard. The regression cases in enter-stale-ime-flag.test.tsx cover stale Enter recovery, genuine-composition suppression, and blur-mediated Send recovery.

Current main has refactored this component, so salvaging requires a localized manual resolution in handleEditorKeyDown rather than a clean cherry-pick; the intended self-heal belongs immediately before the guard now at apps/desktop/src/app/chat/composer/index.tsx:370.

Automated hermes-sweeper review.

[teknium1]

Thanks for this fix! It was salvaged into #86760 (cherry-picked onto current main with your authorship preserved in the commit history) and is now merged. Closing since the work has landed.