onTick set `isDispatching = true`, ran the subscriber callbacks, then reset the
flag, flushed `pending`, and rescheduled with no try/finally. A throwing callback
skipped all three, leaving `isDispatching` stuck true forever: every later
subscribe/unsubscribe queued into `pending` and never ran, and no timer was ever
rescheduled. One bad tick permanently killed every `useAnimation` instance sharing
the (process-wide) scheduler — a non-recoverable wedge.
Wrap the dispatch loop in try/finally so the scheduler invariants are always
restored and the error still propagates (restore-then-rethrow, mirroring
scheduler.ts `doCommit`). Also advance each subscriber's `nextDueTime` BEFORE
invoking its callback, so a thrower can't leave it in the past and make the
post-throw schedule() re-arm a 0ms tight re-throw loop.
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Yunfei He
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