Decouple public and internal act implementation #19745
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In the next major release, we intend to drop support for using the `act` testing helper in production. (It already fires a warning.) The rationale is that, in order for `act` to work, you must either mock the testing environment or add extra logic at runtime. Mocking the testing environment isn't ideal because it requires extra set up for the user. Extra logic at runtime is fine only in development mode — we don't want to slow down the production builds. Since most people only run their tests in development mode, dropping support for production should be fine; if there's demand, we can add it back later using a special testing build that is identical to the production build except for the additional testing logic. One blocker for removing production support is that we currently use `act` to test React itself. We must test React in both development and production modes. So, the solution is to fork `act` into separate public and internal implementations: - *public implementation of `act`* – exposed to users, only works in development mode, uses special runtime logic, does not support partial rendering - *internal implementation of `act`* – private, works in both development and productionm modes, only used by the React Core test suite, uses no special runtime logic, supports partial rendering (i.e. `toFlushAndYieldThrough`) The internal implementation should mostly match the public implementation's behavior, but since it's a private API, it doesn't have to match exactly. It works by mocking the test environment: it uses a mock build of Scheduler to flush rendering tasks, and Jest's mock timers to flush Suspense placeholders. --- In this first commit, I've added the internal forks of `act` and migrated our tests to use them. The public `act` implementation is unaffected for now; I will leave refactoring/clean-up for a later step.
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| flushPassiveEffects, | ||
| /* eslint-enable no-unused-vars */ |
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Is this suppression actually necessary?
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I'll check, doesn't seem like it
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Ah it's because it uses destructuring to get the nth item, but the previous items aren't referenced. I'll switch it to regular array indexing instead.
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Adds back the `TestUtils.act` implementation that I had removed in facebook#19745. This version of `act` is implemented in "userspace" (i.e. not the reconciler), so it doesn't add to the production bundle size. I had removed this in facebook#19745 in favor of the `act` exported by the reconciler because I thought we would remove support for `act` in production in the impending major release. (It currently warns.) However, we've since decided to continue supporting `act` in prod for now, so that it doesn't block people from upgrading to v17. We'll drop support in a future major release. So, to avoid bloating the production bundle size, we need to move the public version of `act` back to "userspace", like it was before. This doesn't negate the main goal of facebook#19745, though, which was to decouple the public version(s) of `act` from the internal one that we use to test React itself.
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Adds back the `TestUtils.act` implementation that I had removed in #19745. This version of `act` is implemented in "userspace" (i.e. not the reconciler), so it doesn't add to the production bundle size. I had removed this in #19745 in favor of the `act` exported by the reconciler because I thought we would remove support for `act` in production in the impending major release. (It currently warns.) However, we've since decided to continue supporting `act` in prod for now, so that it doesn't block people from upgrading to v17. We'll drop support in a future major release. So, to avoid bloating the production bundle size, we need to move the public version of `act` back to "userspace", like it was before. This doesn't negate the main goal of #19745, though, which was to decouple the public version(s) of `act` from the internal one that we use to test React itself.
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Adds back the `TestUtils.act` implementation that I had removed in facebook#19745. This version of `act` is implemented in "userspace" (i.e. not the reconciler), so it doesn't add to the production bundle size. I had removed this in facebook#19745 in favor of the `act` exported by the reconciler because I thought we would remove support for `act` in production in the impending major release. (It currently warns.) However, we've since decided to continue supporting `act` in prod for now, so that it doesn't block people from upgrading to v17. We'll drop support in a future major release. So, to avoid bloating the production bundle size, we need to move the public version of `act` back to "userspace", like it was before. This doesn't negate the main goal of facebook#19745, though, which was to decouple the public version(s) of `act` from the internal one that we use to test React itself.
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Summary: This sync includes the following changes: - **[eaaf4cbce](facebook/react@eaaf4cbce )**: 17.0.1 //<Dan Abramov>// - **[6f62abb58](facebook/react@6f62abb58 )**: Remove usage of Array#fill ([#20071](facebook/react#20071)) //<Dan Abramov>// - **[40cfe1f48](facebook/react@40cfe1f48 )**: Update CHANGELOG.md //<Dan Abramov>// - **[f021a983a](facebook/react@f021a983a )**: Bump versions for 17 ([#20062](facebook/react#20062)) //<Dan Abramov>// - **[d1bb4d851](facebook/react@d1bb4d851 )**: Profiler: Include ref callbacks in onCommit duration ([#20060](facebook/react#20060)) //<Brian Vaughn>// - **[c59c3dfe5](facebook/react@c59c3dfe5 )**: useRef: Warn about reading or writing mutable values during render ([#18545](facebook/react#18545)) //<Brian Vaughn>// - **[7b6cac952](facebook/react@7b6cac952 )**: Improved Profiler commit hooks test ([#20053](facebook/react#20053)) //<Brian Vaughn>// - **[dfb6a4033](facebook/react@dfb6a4033 )**: [Fast Refresh] Fix crashes caused by rogue Proxies ([#20030](facebook/react#20030)) ([#20039](facebook/react#20039)) //<Kai Riemann>// - **[37cb732c5](facebook/react@37cb732c5 )**: Use bitwise OR to define flag masks ([#20044](facebook/react#20044)) //<Andrew Clark>// - **[eb3181e77](facebook/react@eb3181e77 )**: Add Visibility flag for hiding/unhiding trees ([#20043](facebook/react#20043)) //<Andrew Clark>// - **[0dd809bdf](facebook/react@0dd809bdf )**: Remove last schedulePassiveEffectCallback call ([#20042](facebook/react#20042)) //<Andrew Clark>// - **[8df7b7911](facebook/react@8df7b7911 )**: Remove Passive flag from "before mutation" phase ([#20038](facebook/react#20038)) //<Andrew Clark>// - **[c57fe4a2c](facebook/react@c57fe4a2c )**: ReactIs.isValidElementType Unit Test extended with PureComponent case ([#20033](facebook/react#20033)) //<adasq>// - **[02da938fd](facebook/react@02da938fd )**: Don't double-invoke effects in legacy roots ([#20028](facebook/react#20028)) //<Brian Vaughn>// - **[d95c4938d](facebook/react@d95c4938d )**: [EventSystem] Revise onBeforeBlur propagation mechanics ([#20020](facebook/react#20020)) //<Dominic Gannaway>// - **[f46a80ae1](facebook/react@f46a80ae1 )**: Update outdated links and fix two broken links ([#19985](facebook/react#19985)) //<Saikat Guha>// - **[0a4c7c565](facebook/react@0a4c7c565 )**: [Flight] Don't warn for key, but error for ref ([#19986](facebook/react#19986)) //<Sebastian Markbåge>// - **[993ca533b](facebook/react@993ca533b )**: Enable eager listeners statically ([#19983](facebook/react#19983)) //<Dan Abramov>// - **[40c52de96](facebook/react@40c52de96 )**: [Flight] Add Runtime Errors for Non-serializable Values ([#19980](facebook/react#19980)) //<Sebastian Markbåge>// - **[1992d9730](facebook/react@1992d9730 )**: Revert "Temporarily disable Profiler commit hooks flag ([#19900](facebook/react#19900))" ([#19960](facebook/react#19960)) //<Brian Vaughn>// - **[44d39c4d7](facebook/react@44d39c4d7 )**: Removed skip-error-boundaries modifications from old fork ([#19961](facebook/react#19961)) //<Brian Vaughn>// - **[cc77be957](facebook/react@cc77be957 )**: Remove unnecessary error overriding in ([#19949](facebook/react#19949)) //<Paul Doyle>// - **[97625272a](facebook/react@97625272a )**: Debug tracing tests for CPU bound suspense ([#19943](facebook/react#19943)) //<Brian Vaughn>// - **[43363e279](facebook/react@43363e279 )**: Fix codestyle for typeof comparison ([#19928](facebook/react#19928)) //<Eugene Maslovich>// - **[5427b4657](facebook/react@5427b4657 )**: Temporarily disable Profiler commit hooks flag ([#19900](facebook/react#19900)) //<Brian Vaughn>// - **[1faf9e3dd](facebook/react@1faf9e3dd )**: Suspense for CPU-bound trees ([#19936](facebook/react#19936)) //<Andrew Clark>// - **[7f08e908b](facebook/react@7f08e908b )**: Fix missing context to componentDidMount() when double-invoking lifecycles ([#19935](facebook/react#19935)) //<Brian Vaughn>// - **[9198a5cec](facebook/react@9198a5cec )**: Refactor layout effect methods ([#19895](facebook/react#19895)) //<Brian Vaughn>// - **[ba82eea38](facebook/react@ba82eea38 )**: Remove disableSchedulerTimeoutInWorkLoop flag ([#19902](facebook/react#19902)) //<Andrew Clark>// - **[c63741fb3](facebook/react@c63741fb3 )**: offscreen double invoke effects ([#19523](facebook/react#19523)) //<Luna Ruan>// - **[c6917346f](facebook/react@c6917346f )**: Fixed broken Profiler test ([#19894](facebook/react#19894)) //<Brian Vaughn>// - **[87c023b1c](facebook/react@87c023b1c )**: Profiler onRender only called when we do work ([#19885](facebook/react#19885)) //<Brian Vaughn>// - **[81aaee56a](facebook/react@81aaee56a )**: Don't call onCommit et al if there are no effects ([#19863](facebook/react#19863)) //<Andrew Clark>// - **[7355bf575](facebook/react@7355bf575 )**: Consolidate commit phase hook functions ([#19864](facebook/react#19864)) //<Andrew Clark>// - **[bc6b7b6b1](facebook/react@bc6b7b6b1 )**: Don't trigger lazy in DEV during element creation ([#19871](facebook/react#19871)) //<Dan Abramov>// - **[a774502e0](facebook/react@a774502e0 )**: Use single quotes in getComponentName return ([#19873](facebook/react#19873)) //<Gustavo Saiani>// - **[8b2d3783e](facebook/react@8b2d3783e )**: Use Passive flag to schedule onPostCommit ([#19862](facebook/react#19862)) //<Andrew Clark>// - **[50d9451f3](facebook/react@50d9451f3 )**: Improve DevTools editing interface ([#19774](facebook/react#19774)) //<Brian Vaughn>// - **[6fddca27e](facebook/react@6fddca27e )**: Remove passive intervention flag ([#19849](facebook/react#19849)) //<Dan Abramov>// - **[36df9185c](facebook/react@36df9185c )**: chore(docs): Removed outdated comment about fb.me link ([#19830](facebook/react#19830)) //<Adnaan Bheda>// - **[16fb2b6f9](facebook/react@16fb2b6f9 )**: Moved resetChildLanes into complete work ([#19836](facebook/react#19836)) //<Brian Vaughn>// - **[cc581065d](facebook/react@cc581065d )**: [email protected] //<Dan Abramov>// - **[0044805c8](facebook/react@0044805c8 )**: Update CHANGELOG.md //<Dan Abramov>// - **[0f70d4dd6](facebook/react@0f70d4dd6 )**: Consider components in jsx as missing dependencies in typescript-eslint/[email protected] ([#19815](facebook/react#19815)) //<Sebastian Silbermann>// - **[84558c61b](facebook/react@84558c61b )**: Don't visit passive effects during layout phase ([#19809](facebook/react#19809)) //<Andrew Clark>// - **[ad8a0a8cd](facebook/react@ad8a0a8cd )**: [email protected] //<Dan Abramov>// - **[77544a0d6](facebook/react@77544a0d6 )**: Update CHANGELOG.md //<Dan Abramov>// - **[ed4fdfc73](facebook/react@ed4fdfc73 )**: test(eslint-plugin-react-hooks): Run with TS parsers >= 2.x ([#19792](facebook/react#19792)) //<Sebastian Silbermann>// - **[cd75f93c0](facebook/react@cd75f93c0 )**: eslint-plugin-react-hooks: fix compatibility with typescript-eslint/[email protected]+ ([#19751](facebook/react#19751)) //<Matthias Schiffer>// - **[781212aab](facebook/react@781212aab )**: Remove double space in test name ([#19762](facebook/react#19762)) //<Gustavo Saiani>// - **[e7b255341](facebook/react@e7b255341 )**: Internal `act`: Flush timers at end of scope ([#19788](facebook/react#19788)) //<Andrew Clark>// - **[d17086c7c](facebook/react@d17086c7c )**: Decouple public, internal act implementation ([#19745](facebook/react#19745)) //<Andrew Clark>// - **[d38ec17b1](facebook/react@d38ec17b1 )**: [Flight] Set dispatcher for duration of performWork() ([#19776](facebook/react#19776)) //<Joseph Savona>// - **[4f3f7eeb7](facebook/react@4f3f7eeb7 )**: Bugfix: Effect clean up when deleting suspended tree ([#19752](facebook/react#19752)) //<Andrew Clark>// - **[7baf9d412](facebook/react@7baf9d412 )**: Combine Flags and SubtreeFlags types ([#19775](facebook/react#19775)) //<Andrew Clark>// - **[166544360](facebook/react@166544360 )**: Rename effect fields ([#19755](facebook/react#19755)) //<Andrew Clark>// - **[708fa77a7](facebook/react@708fa77a7 )**: Decrease expiration time of input updates ([#19772](facebook/react#19772)) //<Andrew Clark>// - **[36df483af](facebook/react@36df483af )**: Add feature flag to disable scheduler timeout in work loop ([#19771](facebook/react#19771)) //<Ricky>// - **[bcc0aa463](facebook/react@bcc0aa463 )**: Revert "Revert "Remove onScroll bubbling flag ([#19535](facebook/react#19535))" ([#19655](facebook/react#19655))" ([#19761](facebook/react#19761)) //<Dan Abramov>// - **[99cae887f](facebook/react@99cae887f )**: Add failing test for passive effect cleanup functions and memoized components ([#19750](facebook/react#19750)) //<Brian Vaughn>// - **[2cfd73c4d](facebook/react@2cfd73c4d )**: Fix typo in comment (Noticable→Noticeable) ([#19737](facebook/react#19737)) //<Ikko Ashimine>// - **[53e622ca7](facebook/react@53e622ca7 )**: Fix instances of function declaration after return ([#19733](facebook/react#19733)) //<Bhumij Gupta>// - **[b7d18c4da](facebook/react@b7d18c4da )**: Support Babel's envName option in React Refresh plugin ([#19009](facebook/react#19009)) //<Kevin Weber>// - **[1f38dcff6](facebook/react@1f38dcff6 )**: Remove withSuspenseConfig ([#19724](facebook/react#19724)) //<Andrew Clark>// - **[1396e4a8f](facebook/react@1396e4a8f )**: Fixes eslint warning when node type is ChainExpression ([#19680](facebook/react#19680)) //<Pascal Fong Kye>// - **[a8500be89](facebook/react@a8500be89 )**: Add `startTransition` as a known stable method ([#19720](facebook/react#19720)) //<Andrew Clark>// - **[380dc95de](facebook/react@380dc95de )**: Revert "Append text string to <Text> error message ([#19581](facebook/react#19581))" ([#19723](facebook/react#19723)) //<Timothy Yung>// - **[ddd1faa19](facebook/react@ddd1faa19 )**: Remove config argument from useTransition ([#19719](facebook/react#19719)) //<Andrew Clark>// - **[92fcd46cc](facebook/react@92fcd46cc )**: Replace SuspenseConfig object with an integer ([#19706](facebook/react#19706)) //<Andrew Clark>// - **[b754caaaf](facebook/react@b754caaaf )**: Enable eager listeners in open source ([#19716](facebook/react#19716)) //<Dan Abramov>// - **[c1ac05215](facebook/react@c1ac05215 )**: [Flight] Support more element types and Hooks for Server and Hybrid Components ([#19711](facebook/react#19711)) //<Dan Abramov>// - **[1eaafc9ad](facebook/react@1eaafc9ad )**: Clean up timeoutMs-related implementation details ([#19704](facebook/react#19704)) //<Andrew Clark>// - **[8da0da093](facebook/react@8da0da093 )**: Disable timeoutMs argument ([#19703](facebook/react#19703)) //<Andrew Clark>// - **[60ba723bf](facebook/react@60ba723bf )**: Add SuspenseList to devTools ([#19684](facebook/react#19684)) //<Ben Pernick>// - **[5564f2c95](facebook/react@5564f2c95 )**: Add React.startTransition ([#19696](facebook/react#19696)) //<Ricky>// - **[c4e0768d7](facebook/react@c4e0768d7 )**: Remove unused argument from `finishConcurrentRender` ([#19689](facebook/react#19689)) //<inottn>// - **[848bb2426](facebook/react@848bb2426 )**: Attach Listeners Eagerly to Roots and Portal Containers ([#19659](facebook/react#19659)) //<Dan Abramov>// - **[d2e914ab4](facebook/react@d2e914ab4 )**: Remove remaining references to effect list ([#19673](facebook/react#19673)) //<Andrew Clark>// - **[d6e433899](facebook/react@d6e433899 )**: Use Global Render Timeout for CPU Suspense ([#19643](facebook/react#19643)) //<Sebastian Markbåge>// - **[64ddef44c](facebook/react@64ddef44c )**: Revert "Remove onScroll bubbling flag ([#19535](facebook/react#19535))" ([#19655](facebook/react#19655)) //<Dan Abramov>// - **[dd651df05](facebook/react@dd651df05 )**: Keep onTouchStart, onTouchMove, and onWheel passive ([#19654](facebook/react#19654)) //<Dan Abramov>// - **[b8fa09e9e](facebook/react@b8fa09e9e )**: provide profiling bundle for react-reconciler ([#19559](facebook/react#19559)) //<Julien Gilli>// - **[23595ff59](facebook/react@23595ff59 )**: Add missing param to safelyCallDestroy() ([#19638](facebook/react#19638)) //<Brian Vaughn>// - **[ee409ea3b](facebook/react@ee409ea3b )**: change destroy to safelyCallDestroy ([#19605](facebook/react#19605)) //<Luna Ruan>// - **[bcca5a6ca](facebook/react@bcca5a6ca )**: Always skip unmounted/unmounting error boundaries ([#19627](facebook/react#19627)) //<Brian Vaughn>// - **[1a41a196b](facebook/react@1a41a196b )**: Append text string to <Text> error message ([#19581](facebook/react#19581)) //<Timothy Yung>// - **[e4afb2fdd](facebook/react@e4afb2fdd )**: [email protected] //<Dan Abramov>// - **[ced05c46c](facebook/react@ced05c46c )**: Update CHANGELOG.md //<Dan Abramov>// - **[702fad4b1](facebook/react@702fad4b1 )**: refactor fb.me redirect link to reactjs.org/link ([#19598](facebook/react#19598)) //<CY Lim>// - **[49cd77d24](facebook/react@49cd77d24 )**: fix: leak strict mode with UMD builds ([#19614](facebook/react#19614)) //<Toru Kobayashi>// - **[ffb749c95](facebook/react@ffb749c95 )**: Improve error boundary handling for unmounted subtrees ([#19542](facebook/react#19542)) //<Brian Vaughn>// - **[9b35dd2fc](facebook/react@9b35dd2fc )**: Permanently removed component stacks from scheduling profiler data ([#19615](facebook/react#19615)) //<Brian Vaughn>// - **[3f8115cdd](facebook/react@3f8115cdd )**: Remove `didTimeout` check from work loop //<Andrew Clark>// - **[9abc2785c](facebook/react@9abc2785c )**: Remove wasteful checks from `shouldYield` //<Andrew Clark>// - **[1d5e10f70](facebook/react@1d5e10f70 )**: [eslint-plugin-react-hooks] Report constant constructions ([#19590](facebook/react#19590)) //<Jordan Eldredge>// - **[dab0854c5](facebook/react@dab0854c5 )**: Move commit passive unmount/mount to CommitWork ([#19599](facebook/react#19599)) //<Sebastian Markbåge>// - **[ccb6c3945](facebook/react@ccb6c3945 )**: Remove unused argument ([#19600](facebook/react#19600)) //<inottn>// - **[629125555](facebook/react@629125555 )**: [Scheduler] Re-throw unhandled errors ([#19595](facebook/react#19595)) //<Andrew Clark>// - **[b8ed6a1aa](facebook/react@b8ed6a1aa )**: [Scheduler] Call postTask directly ([#19551](facebook/react#19551)) //<Andrew Clark>// - **[ce37bfad5](facebook/react@ce37bfad5 )**: Remove resolutions from test renderer package.json ([#19577](facebook/react#19577)) //<Dan Abramov>// - **[2704bb537](facebook/react@2704bb537 )**: Add ReactVersion to SchedulingProfiler render scheduled marks ([#19553](facebook/react#19553)) //<Kartik Choudhary>// - **[0c52e24cb](facebook/react@0c52e24cb )**: Support inner component _debugOwner in memo ([#19556](facebook/react#19556)) //<Brian Vaughn>// - **[0cd9a6de5](facebook/react@0cd9a6de5 )**: Parallelize Jest in CI ([#19552](facebook/react#19552)) //<Andrew Clark>// - **[a63893ff3](facebook/react@a63893ff3 )**: Warn about undefined return value for memo and forwardRef ([#19550](facebook/react#19550)) //<Brian Vaughn>// - **[32ff42868](facebook/react@32ff42868 )**: Add feature flag for setting update lane priority ([#19401](facebook/react#19401)) //<Ricky>// - **[5bdd4c8c6](facebook/react@5bdd4c8c6 )**: Remove unused argument from call to jest method ([#19546](facebook/react#19546)) //<Gustavo Saiani>// - **[a5fed98a9](facebook/react@a5fed98a9 )**: Register more node types that are used later as JSXIdentifiers ([#19514](facebook/react#19514)) //<Mateusz Burzyński>// - **[f77c7b9d7](facebook/react@f77c7b9d7 )**: Re-add discrete flushing timeStamp heuristic (behind flag) ([#19540](facebook/react#19540)) //<Dominic Gannaway>// Changelog: [general] [feature] Upgrade to React 17 Reviewed By: cpojer Differential Revision: D24491201 fbshipit-source-id: c947da9dcccbd614e9dc58f3339b63e24829aca7
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In the next major release, we intend to drop support for using the `act` testing helper in production. (It already fires a warning.) The rationale is that, in order for `act` to work, you must either mock the testing environment or add extra logic at runtime. Mocking the testing environment isn't ideal because it requires extra set up for the user. Extra logic at runtime is fine only in development mode — we don't want to slow down the production builds. Since most people only run their tests in development mode, dropping support for production should be fine; if there's demand, we can add it back later using a special testing build that is identical to the production build except for the additional testing logic. One blocker for removing production support is that we currently use `act` to test React itself. We must test React in both development and production modes. So, the solution is to fork `act` into separate public and internal implementations: - *public implementation of `act`* – exposed to users, only works in development mode, uses special runtime logic, does not support partial rendering - *internal implementation of `act`* – private, works in both development and productionm modes, only used by the React Core test suite, uses no special runtime logic, supports partial rendering (i.e. `toFlushAndYieldThrough`) The internal implementation should mostly match the public implementation's behavior, but since it's a private API, it doesn't have to match exactly. It works by mocking the test environment: it uses a mock build of Scheduler to flush rendering tasks, and Jest's mock timers to flush Suspense placeholders. --- In this first commit, I've added the internal forks of `act` and migrated our tests to use them. The public `act` implementation is unaffected for now; I will leave refactoring/clean-up for a later step.
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Adds back the `TestUtils.act` implementation that I had removed in facebook#19745. This version of `act` is implemented in "userspace" (i.e. not the reconciler), so it doesn't add to the production bundle size. I had removed this in facebook#19745 in favor of the `act` exported by the reconciler because I thought we would remove support for `act` in production in the impending major release. (It currently warns.) However, we've since decided to continue supporting `act` in prod for now, so that it doesn't block people from upgrading to v17. We'll drop support in a future major release. So, to avoid bloating the production bundle size, we need to move the public version of `act` back to "userspace", like it was before. This doesn't negate the main goal of facebook#19745, though, which was to decouple the public version(s) of `act` from the internal one that we use to test React itself.
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In the next major release, we intend to drop support for using the
acttesting helper in production. (It already fires a warning.) The rationale is that, to implementact, we must either mock the testing environment or add extra logic at runtime. Mocking the testing environment isn't ideal because it requires extra set up for the user. Extra logic at runtime is fine only in development mode — we don't want to slow down the production builds.Since most people only run their tests in development mode, dropping support for production should be fine; if there's demand, we can add it back later using a special testing build that is identical to the production build except for the additional testing logic.
One blocker for removing production support is that we currently use
actto test React itself. We must test React in both development and production modes.So, the solution is to fork
actinto separate public and internal implementations:act– exposed to users, only works in development mode, uses special runtime logic, does not support partial renderingact– private, works in both development and production modes, only used by the React Core test suite, uses no special runtime logic, supports partial rendering (i.e.toFlushAndYieldThrough)The internal implementation should mostly match the public implementation's behavior, but since it's a private API, it doesn't have to match exactly. It works by mocking the test environment: it uses a mock build of Scheduler to flush rendering tasks, and Jest's mock timers to flush Suspense placeholders.
In this first PR, I've added the internal forks of
actand migrated our tests to use them. The publicactimplementation is unaffected for now; I will leave refactoring/clean-up for a later step.There is an internal version of
actfor each of React DOM, React Test Renderer, and React Noop, since we use all three to test React itself. These are intentionally non-DRY. Not so much for performance reasons (these are only used for our internal tests), just that it's too early to pick an abstraction.