fix(core): stop superseded loop chains on re-render#2471
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A re-render that flipped `loop` from truthy to falsy did not stop the animation, because the in-flight `flushUpdate` chain captured its own `loop` value and kept scheduling iterations alongside the new update. The Controller now tags each loop chain with a generation token and exits the recursion when a newer external update has superseded it. Closes #1193.
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This was referenced May 22, 2026
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Closes #1193.
Summary
Toggling
loopfrom truthy to falsy on a re-render did not actually stop the animation. The in-flightflushUpdatechain captured its ownloopvalue in a closure, so the capturedtruekept the recursion alive even when the new top-level update arrived withloop: false. Both chains then ran in parallel — the old one scheduled iterations indefinitely, the new one was a no-op.Fix
Controllernow carries a_lastLoopIdgeneration token. A top-level external update bumps the token only when it could express a different loop intent (i.e. it mentionsloopand is not an internal sub-step fromrunAsync'sanimate, which carriesparentId, nor apause/resumelifecycle call). Each loop chain captures its token; before recursing into the next iteration it checks the token still matches_lastLoopIdand otherwise exits.This is the minimal scoping required to avoid regressions in the three existing loop tests that rely on
runAsyncsub-steps and pause/resume cycles preserving the chain.A regression test mirroring the reported shape (
loop: true → loop: falsevia a secondctrl.start) is added inController.test.ts.