Eager bailout optimization should always compare to latest reducer #15124
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This name is a bit more descriptive.
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I tried fixing it like this, and it also passed tests: 6670512. Is my fix wrong? If yes, can we add a new case that this naïve fix would fail? |
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@gaearon That's essentially the same fix except in yours doesn't account for the render phase updates path. So I think it would break if an earlier state in the same component gets a render phase update, and then a subsequent inline reducer closes over that. I'll see if I can write a test case where that would fail. |
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Added additional test that fails if reducer is not updated in the render phase updates branch. |
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…acebook#15124) * Eager bailout optimization should always compare to latest reducer * queue.eagerReducer -> queue.lastRenderedReducer This name is a bit more descriptive. * Add test case that uses preceding render phase update
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Based on a bug report by @pomber
https://mobile.twitter.com/pomber/status/1106667842844401670
The issue was that the queue contains a reference to the last rendered reducer, but we weren't updating it in all cases, so sometimes it was stale, triggering the bailout incorrectly.
The original bug report (https://codesandbox.io/s/yj605043yv) had an additional bug in it that made it a bit more confusing, which is it did not specify an initial state. I did not include that part in my test case because it wasn't relevant to the actual underlying bug.