Make time-slicing opt-in #21072
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Make time-slicing opt-in #21072
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| }); | ||
| if (gate(flags => flags.enableSyncDefaultUpdates)) { | ||
| React.unstable_startTransition(() => { | ||
| // TODO: Batched updates need to be inside startTransition? |
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What's going on here? Seems like a bug
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We're not taking the executionContext into account when scheduling the sync updates, so the updates inside of batchedUpdates are each flushed synchronously
This would fix it in ensureRootIsScheduled, but I don't know enough about batchedUpdates or executionContext to know if this is the desired behavior/fix:
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Let's follow up with this, I want to merge so that I don't get another merge conflict since this is so big.
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Nvm, I think this is fine. batchedUpdates doesn't change the priority, so it makes sense you need to wrap these with startTransition when the sync-by-default flag is on.
I had misinterpreted the TODO as saying that without startTransition, the updates wouldn't be batched.
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packages/react-reconciler/src/__tests__/SchedulingProfiler-test.internal.js
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This reverts commit 933880b.
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Summary: This sync includes the following changes: - **[f7cdc8936](facebook/react@f7cdc8936 )**: Also turn off enableSyncDefaultUpdates in RN test renderer ([#21293](facebook/react#21293)) //<Ricky>// - **[4c9eb2af1](facebook/react@4c9eb2af1 )**: Add dynamic flags to React Native ([#21291](facebook/react#21291)) //<Ricky>// - **[9eddfbf5a](facebook/react@9eddfbf5a )**: [Fizz] Two More Fixes ([#21288](facebook/react#21288)) //<Sebastian Markbåge>// - **[11b07597e](facebook/react@11b07597e )**: Fix classes ([#21283](facebook/react#21283)) //<Sebastian Markbåge>// - **[96d00b9bb](facebook/react@96d00b9bb )**: [Fizz] Random Fixes ([#21277](facebook/react#21277)) //<Sebastian Markbåge>// - **[81ef53953](facebook/react@81ef53953 )**: Always insert a dummy node with an ID into fallbacks ([#21272](facebook/react#21272)) //<Sebastian Markbåge>// - **[a4a940d7a](facebook/react@a4a940d7a )**: [Fizz] Add unsupported Portal/Scope components ([#21261](facebook/react#21261)) //<Sebastian Markbåge>// - **[f4d7a0f1e](facebook/react@f4d7a0f1e )**: Implement useOpaqueIdentifier ([#21260](facebook/react#21260)) //<Sebastian Markbåge>// - **[dde875dfb](facebook/react@dde875dfb )**: [Fizz] Implement Hooks ([#21257](facebook/react#21257)) //<Sebastian Markbåge>// - **[a597c2f5d](facebook/react@a597c2f5d )**: [Fizz] Fix reentrancy bug ([#21270](facebook/react#21270)) //<Sebastian Markbåge>// - **[15e779d92](facebook/react@15e779d92 )**: Reconciler should inject its own version into DevTools hook ([#21268](facebook/react#21268)) //<Brian Vaughn>// - **[4f76a28c9](facebook/react@4f76a28c9 )**: [Fizz] Implement New Context ([#21255](facebook/react#21255)) //<Sebastian Markbåge>// - **[82ef450e0](facebook/react@82ef450e0 )**: remove obsolete SharedArrayBuffer ESLint config ([#21259](facebook/react#21259)) //<Henry Q. Dineen>// - **[dbadfa2c3](facebook/react@dbadfa2c3 )**: [Fizz] Classes Follow Up ([#21253](facebook/react#21253)) //<Sebastian Markbåge>// - **[686b635b7](facebook/react@686b635b7 )**: Prevent reading canonical property of null ([#21242](facebook/react#21242)) //<Joshua Gross>// - **[bb88ce95a](facebook/react@bb88ce95a )**: Bugfix: Don't rely on `finishedLanes` for passive effects ([#21233](facebook/react#21233)) //<Andrew Clark>// - **[343710c92](facebook/react@343710c92 )**: [Fizz] Fragments and Iterable support ([#21228](facebook/react#21228)) //<Sebastian Markbåge>// - **[933880b45](facebook/react@933880b45 )**: Make time-slicing opt-in ([#21072](facebook/react#21072)) //<Ricky>// - **[b0407b55f](facebook/react@b0407b55f )**: Support more empty types ([#21225](facebook/react#21225)) //<Sebastian Markbåge>// - **[39713716a](facebook/react@39713716a )**: Merge isObject branches ([#21226](facebook/react#21226)) //<Sebastian Markbåge>// - **[8a4a59c72](facebook/react@8a4a59c72 )**: Remove textarea special case from child fiber ([#21222](facebook/react#21222)) //<Sebastian Markbåge>// - **[dc108b0f5](facebook/react@dc108b0f5 )**: Track which fibers scheduled the current render work ([#15658](facebook/react#15658)) //<Brian Vaughn>// - **[6ea749170](facebook/react@6ea749170 )**: Fix typo in comment ([#21214](facebook/react#21214)) //<inokawa>// - **[b38ac13f9](facebook/react@b38ac13f9 )**: DevTools: Add post-commit hook ([#21183](facebook/react#21183)) //<Brian Vaughn>// - **[b943aeba8](facebook/react@b943aeba8 )**: Fix: Passive effect updates are never sync ([#21215](facebook/react#21215)) //<Andrew Clark>// - **[d389c54d1](facebook/react@d389c54d1 )**: Offscreen: Use JS stack to track hidden/unhidden subtree state ([#21211](facebook/react#21211)) //<Brian Vaughn>// - **[c486dc1a4](facebook/react@c486dc1a4 )**: Remove unnecessary processUpdateQueue ([#21199](facebook/react#21199)) //<Sebastian Markbåge>// - **[cf45a623a](facebook/react@cf45a623a )**: [Fizz] Implement Classes ([#21200](facebook/react#21200)) //<Sebastian Markbåge>// - **[75c616554](facebook/react@75c616554 )**: Include actual type of `Profiler#id` on type mismatch ([#20306](facebook/react#20306)) //<Sebastian Silbermann>// - **[1214b302e](facebook/react@1214b302e )**: test: Fix "couldn't locate all inline snapshots" ([#21205](facebook/react#21205)) //<Sebastian Silbermann>// - **[1a02d2792](facebook/react@1a02d2792 )**: style: delete unused isHost check ([#21203](facebook/react#21203)) //<wangao>// - **[782f689ca](facebook/react@782f689ca )**: Don't double invoke getDerivedStateFromProps for module pattern ([#21193](facebook/react#21193)) //<Sebastian Markbåge>// - **[e90c76a65](facebook/react@e90c76a65 )**: Revert "Offscreen: Use JS stack to track hidden/unhidden subtree state" ([#21194](facebook/react#21194)) //<Brian Vaughn>// - **[1f8583de8](facebook/react@1f8583de8 )**: Offscreen: Use JS stack to track hidden/unhidden subtree state ([#21192](facebook/react#21192)) //<Brian Vaughn>// - **[ad6e6ec7b](facebook/react@ad6e6ec7b )**: [Fizz] Prepare Recursive Loop for More Types ([#21186](facebook/react#21186)) //<Sebastian Markbåge>// - **[172e89b4b](facebook/react@172e89b4b )**: Reland Remove redundant initial of isArray ([#21188](facebook/react#21188)) //<Sebastian Markbåge>// - **[7c1ba2b57](facebook/react@7c1ba2b57 )**: Proposed new Suspense layout effect semantics ([#21079](facebook/react#21079)) //<Brian Vaughn>// - **[316aa3686](facebook/react@316aa3686 )**: [Scheduler] Fix de-opt caused by out-of-bounds access ([#21147](facebook/react#21147)) //<Andrey Marchenko>// - **[b4f119cdf](facebook/react@b4f119cdf )**: Revert "Remove redundant initial of isArray ([#21163](facebook/react#21163))" //<Sebastian Markbage>// - **[c03197063](facebook/react@c03197063 )**: Revert "apply prettier ([#21165](facebook/react#21165))" //<Sebastian Markbage>// - **[94fd1214d](facebook/react@94fd1214d )**: apply prettier ([#21165](facebook/react#21165)) //<Behnam Mohammadi>// - **[b130a0f5c](facebook/react@b130a0f5c )**: Remove redundant initial of isArray ([#21163](facebook/react#21163)) //<Behnam Mohammadi>// - **[2c9fef32d](facebook/react@2c9fef32d )**: Remove redundant initial of hasOwnProperty ([#21134](facebook/react#21134)) //<Behnam Mohammadi>// - **[1cf9978d8](facebook/react@1cf9978d8 )**: Don't pass internals to callbacks ([#21161](facebook/react#21161)) //<Sebastian Markbåge>// - **[b9e4c10e9](facebook/react@b9e4c10e9 )**: [Fizz] Implement all the DOM attributes and special cases ([#21153](facebook/react#21153)) //<Sebastian Markbåge>// - **[f8ef4ff57](facebook/react@f8ef4ff57 )**: Flush discrete passive effects before paint ([#21150](facebook/react#21150)) //<Andrew Clark>// - **[b48b38af6](facebook/react@b48b38af6 )**: Support nesting of startTransition and flushSync (alt) ([#21149](facebook/react#21149)) //<Sebastian Markbåge>// Changelog: [General][Changed] - React Native sync for revisions c9aab1c...f7cdc89 jest_e2e[run_all_tests] Reviewed By: rickhanlonii Differential Revision: D27740113 fbshipit-source-id: 6e27204d78e3e16ed205170006cb97c0d6bfa957
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Instead of `performSyncWorkOnRoot`. The conceptual model is that the only difference between sync default updates (in React 18) and concurrent default updates (in a future major release) is time slicing. All other behavior should be the same (i.e. the stuff in `finishConcurrentRender`). Given this, I think it makes more sense to model the implementation this way, too. This exposed a quirk in the previous implementation where non-sync work was sometimes mistaken for sync work and flushed too early. In the new implementation, `performSyncWorkOnRoot` is only used for truly synchronous renders (i.e. `SyncLane`), which should make these mistakes less common. Fixes most of the tests marked with TODOs from facebook#21072.
acdlite
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Instead of `performSyncWorkOnRoot`. The conceptual model is that the only difference between sync default updates (in React 18) and concurrent default updates (in a future major release) is time slicing. All other behavior should be the same (i.e. the stuff in `finishConcurrentRender`). Given this, I think it makes more sense to model the implementation this way, too. This exposed a quirk in the previous implementation where non-sync work was sometimes mistaken for sync work and flushed too early. In the new implementation, `performSyncWorkOnRoot` is only used for truly synchronous renders (i.e. `SyncLane`), which should make these mistakes less common. Fixes most of the tests marked with TODOs from #21072.
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* Add enableSyncDefaultUpdates feature flag * Add enableSyncDefaultUpdates implementation * Fix tests * Switch feature flag to true by default * Finish concurrent render whenever for non-sync lanes * Also return DefaultLane with eventLane * Gate interruption test * Add continuout native event test * Fix tests from rebasing main * Hardcode lanes, remove added export * Sync forks
koto
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Instead of `performSyncWorkOnRoot`. The conceptual model is that the only difference between sync default updates (in React 18) and concurrent default updates (in a future major release) is time slicing. All other behavior should be the same (i.e. the stuff in `finishConcurrentRender`). Given this, I think it makes more sense to model the implementation this way, too. This exposed a quirk in the previous implementation where non-sync work was sometimes mistaken for sync work and flushed too early. In the new implementation, `performSyncWorkOnRoot` is only used for truly synchronous renders (i.e. `SyncLane`), which should make these mistakes less common. Fixes most of the tests marked with TODOs from facebook#21072.
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Overview
This PR adds a new flag to synchronously flush updates in a task by default.
This has the practical effect of making time-slicing optional in the next major version.
Motivation
As we've iterated on concurrent features like
SuspenseandstartTransition, we've seen the benefits of Time-slicing not only in those APIs, but also for time-slicing updates by default as shown in the talk above. Time slicing allows React to yield to other work while rendering and allow higher priority tasks such as user interactions, network events, or other renders to be processed. Based on this research, time-slicing by default is the future of React.However, time-slicing can cause issues with existing code that was not written with yielding in mind. For example, by yielding to other work, we allow for the possibility that external sources of information read during render are updated. This can cause tearing - where part of the UI displays an old value and another part shows a new value. This isn't a React specific bug - it's the logical consequence of concurrency.
We've introduced warnings and dev-behavior to StrictMode to help users catch these types of issues, however there is still a large part of the community that is not ready for the new behavior by default. If we were to keep time-slicing on by default for all updates, then most users would need to convert their entire app to support concurrency all at once before upgrading to the next major version of React.
Changes
This PR updates the default behavior of React in the next major version to flush updates synchronously in a task, similar to how the current behavior works. This means users will not use time-slicing by default when upgrading to the concurrent root, and their app will continue to synchronously render (almost) the same as before.
To opt-in to time-slicing, users can incrementally adopt concurrent features such are
Suspense(which will concurrently re-try rendering with time-slicing) orstartTransition(which will render updates concurrently with time-slicing). This strategy allows users to begin to use concurrent features in subtrees of their app, while working to adoptStrictModeglobally and prepare for the future of React with time-slicing by default.