We have behaviour divergence for act() between prod and dev (specifically, act() + concurrent mode does not flush fallbacks in prod. This doesn't affect anyone in OSS yet)
We also don't have a good story for writing tests in prod (and what from what I gather, nobody really writes tests in prod mode).
We could have wiped out act() in prod builds, except that _we_ ourselves use act() for our tests when we run them in prod mode.
This PR is a compromise to all of this. We will log a warning if you try to use act() in prod mode, and we silence it in our test suites.
Concurrent/Batched mode tests should always be run with a mocked scheduler (v17 or not). This PR adds a warning for the same. I'll put up a separate PR to the docs with a page detailing how to mock the scheduler.
Not returning the value of flushPassiveEffects() in flushWork() meant that with async act, we wouldn't flush all work with cascading effects. This PR fixes that oversight, and adds some tests to catch this in the future.
Given this snippet:
```jsx
TestRenderer.act(() => {
TestUtils.act(() => {
TestRenderer.create(<Effecty />);
});
});
```
We want to make sure that all work is only flushed on exiting the outermost act().
Now, naively doing this based on actingScopeDepth would work with a mocked scheduler, where flushAll() would flush all work across renderers.
This doesn't work without mocking the scheduler though; and where flushing work only works per renderer. So we disable this behaviour for a non-mocked scenario. This seems like an ok tradeoff.
* [fail] reset IsThisRendererActing correctly
I missed this in https://github.com/facebook/react/pull/16039. I'd pointed at the wrong previous state, corrupting it in further use. This PR fixes that, and adds a test to make sure it doesn't happen again.
* warn for unacted effects only in strict mode
* allow nested `act()`s from different renderers
There are usecases where multiple renderers need to oprate inside an act() scope
- ReactDOM.render being used inside another component tree. The parent component will be rendered using ReactTestRenderer.create for a snapshot test or something.
- a ReactDOM instance interacting with a ReactTestRenderer instance (like for the new devtools)
This PR changes the way the acting sigils operate to allow for this. It keeps 2 booleans, one attached to React, one attached to the renderer. act() changes these values, and the workloop reads them to decide what warning to trigger.
I also renamed shouldWarnUnactedUpdates to warnsIfNotActing
* s/ReactIsActing/IsSomeRendererActing and s/ReactRendererIsActing/IsThisRendererActing
* use toWarnDev for dom fixture tests
forks toWarnDev from root into fixture/dom, updates tes tests to use it
* disable act() warnings for react-art()
- For 'secondary' renderers like react-act, we don't want to fire missing act() warnings; the wrapping renderer will fire warnings anyway, and when it flushes, it flushes effects *across* renderers.
- I could have used isPrimaryRenderer as the flag, but this is marked as false for react-test-renderer, and we *do* want the warning to fire for it. Hence a new flag.
* add missing dependency `art` to fixtures/dom
* reset scope depth on synchronous errors
we weren't resetting the acting scope depth on sync errors thrown in the callback. this fixes that.
* typos
* add a test to make sure sync error propagate
* warn when using the wrong renderer's act around another renderer's updates
like it says. it uses a real object as the sigil (instead of just a boolean). specifically, it uses a renderer's flushPassiveEffects as the sigil. We also run tests for this separate from our main suite (which doesn't allow loading multiple renderers in a suite), but makes sure to run this in CI as well.
* unneeded (and wrong) comment
* run the dom fixture on CI
* update the sigil only in __DEV__
* remove the obnoxious comment
* use an explicit export for the sigil
* Rename ReactFiberScheduler to ReactFiberWorkLoop
The scheduling part is mostly extracted out to the scheduler package.
What's remaining is mostly around the loop around each section of work.
I name it something with Work in it because it's very related to the
BeginWork, CompleteWork and UnwindWork sections.
* Extract throwException from UnwindWork
Our throwing works more like algebraic effects in that it's a separate
phase where we find a handler and we later unwind.
* s/flushPassiveEffects/unstable_flushWithoutYielding
a first crack at flushing the scheduler manually from inside act(). uses unstable_flushWithoutYielding(). The tests that changed, mostly replaced toFlushAndYield(...) with toHaveYielded(). For some tests that tested the state of the tree before flushing effects (but still after updates), I replaced act() with bacthedUpdates().
* ugh lint
* pass build, flushPassiveEffects returns nothing now
* pass test-fire
* flush all work (not just effects), add a compatibility mode
of note, unstable_flushWithoutYielding now returns a boolean much like flushPassiveEffects
* umd build for scheduler/unstable_mock, pass the fixture with it
* add a comment to Shcduler.umd.js for why we're exporting unstable_flushWithoutYielding
* run testsutilsact tests in both sync/concurrent modes
* augh lint
* use a feature flag for the missing mock scheduler warning
I also tried writing a test for it, but couldn't get the scheduler to unmock. included the failing test.
* Update ReactTestUtilsAct-test.js
- pass the mock scheduler warning test,
- rewrite some tests to use Scheduler.yieldValue
- structure concurrent/legacy suites neatly
* pass failing tests in batchedmode-test
* fix pretty/lint/import errors
* pass test-build
* nit: pull .create(null) out of the act() call
* Add Batched Mode
React has an unfortunate quirk where updates are sometimes synchronous
-- where React starts rendering immediately within the call stack of
`setState` — and sometimes batched, where updates are flushed at the
end of the current event. Any update that originates within the call
stack of the React event system is batched. This encompasses most
updates, since most updates originate from an event handler like
`onClick` or `onChange`. It also includes updates triggered by lifecycle
methods or effects. But there are also updates that originate outside
React's event system, like timer events, network events, and microtasks
(promise resolution handlers). These are not batched, which results in
both worse performance (multiple render passes instead of single one)
and confusing semantics.
Ideally all updates would be batched by default. Unfortunately, it's
easy for components to accidentally rely on this behavior, so changing
it could break existing apps in subtle ways.
One way to move to a batched-by-default model is to opt into Concurrent
Mode (still experimental). But Concurrent Mode introduces additional
semantic changes that apps may not be ready to adopt.
This commit introduces an additional mode called Batched Mode. Batched
Mode enables a batched-by-default model that defers all updates to the
next React event. Once it begins rendering, React will not yield to
the browser until the entire render is finished.
Batched Mode is superset of Strict Mode. It fires all the same warnings.
It also drops the forked Suspense behavior used by Legacy Mode, in favor
of the proper semantics used by Concurrent Mode.
I have not added any public APIs that expose the new mode yet. I'll do
that in subsequent commits.
* Suspense in Batched Mode
Should have same semantics as Concurrent Mode.
* Use RootTag field to configure type of root
There are three types of roots: Legacy, Batched, and Concurrent.
* flushSync should not flush batched work
Treat Sync and Batched expiration times separately. Only Sync updates
are pushed to our internal queue of synchronous callbacks.
Renamed `flushImmediateQueue` to `flushSyncCallbackQueue` for clarity.
This took a while, but I'm happy I went through it. Some key moments - recursively flushing effects, flushing microtasks on each async turn, and my team's uncompromising philosophy on code reuse. Really happy with this. I still want to expand test coverage, and I have some more small related todos, but this is good to land. On to the next one.
Soundtrack to landing this - https://open.spotify.com/track/0MF8I8OUo8kytiOo8aSHYq?si=gSWqUheKQbiQDXzptCXHTg
* hacked up act(async () => {...})
* move stuff around
* merge changes
* abstract .act warnings and stuff. all renderers. pass all tests.
* move testutils.act back into testutils
* move into scheduler, rename some bits
* smaller bundle
* a comment for why we don't do typeof === 'function'
* fix test
* pass tests - fire, prod
* lose actContainerElement
* tighter
* write a test for TestRenderer
it's an odd one, because not only does sync act not flush effects correctly, but the async one does (wut). verified it's fine with the dom version.
* lint
* rewrote to move flushing logic closer to the renderer
the scheduler's `flushPassiveEffects` didn't work as expected for the test renderer, so I decided to go back to the hack (rendering a dumb container) This also makes reactdom not as heavy (by a few bytes, but still).
* move it around so the delta isn't too bad
* cleanups
fix promise chaining
propagate errors correctly
test for thenable the 'right' way
more tests!
tidier!
ponies!
* Stray comment
* recursively flush effects
* fixed tests
* lint, move noop.act into react-reconciler
* microtasks when checking if called, s/called/calledLog, cleanup
* pass fb lint
we could have globally changed our eslint config to assume Promise is available, but that means we expect a promise polyfill on the page, and we don't yet. this code is triggered only in jest anyway, and we're fairly certain Promise will be available there. hence, the once-off disable for the check
* shorter timers, fix a test, test for Promise
* use global.Promise for existence check
* flush microtasks
* a version that works in browsers (that support postMessage)
I also added a sanity fixture inside fixtures/dom/ mostly for me.
* hoist flushEffectsAndMicroTasks
* pull out tick logic from ReactFiberScheduler
* fix await act (...sync) hanging
- fix a hang when awaiting sync logic
- a better async/await test for test renderer
* feedback changes
- use node's setImmediate if available
- a warning if MessageChannel isn't available
- rename some functions
* pass lint/flow checks (without requiring a Promise polyfill/exclusion)
* prettier
the prettiest, even.
* use globalPromise for the missed await warning
* __DEV__ check for didWarnAboutMessageChannel
* thenables and callbacks instead of promises, pass flow/lint
* tinier. better.
- pulled most bits out of FiberScheduler
- actedUpdates uses callbacks now
* pass build validation
* augh prettier
* golfing 7 more chars
* Test that effects are not flushed without also flushing microtasks
* export doesHavePendingPassiveEffects, nits
* createAct()
* dead code
* missed in merge?
* lose the preflushing bits
* ugh prettier
* removed `actedUpdates()`, created shared/actingUpdatesScopeDepth
* rearrange imports so builds work, remove the hack versions of flushPassiveEffects
* represent actingUpdatesScopeDepth as a tuple [number]
* use a shared flag on React.__SECRET...
* remove createAct, setup act for all relevant renderers
* review feedback
shared/enqueueTask
import ReactSharedInternals from 'shared/ReactSharedInternals';
simpler act() internals
ReactSharedInternals.ReactShouldWarnActingUpdates
* move act() implementation into createReactNoop
* warnIfNotCurrentlyActingUpdatesInDev condition check order
* Add command to run tests in persistent mode
* Convert Suspense fuzz tester to use noop renderer
So we can run it in persistent mode, too.
* Don't mutate stateNode in appendAllChildren
We can't mutate the stateNode in appendAllChildren because the children
could be current.
This is a bit weird because now the child that we append is different
from the one on the fiber stateNode. I think this makes conceptual
sense, but I suspect this likely breaks an assumption in Fabric.
With this approach, we no longer need to clone to unhide the children,
so I removed those host config methods.
Fixes bug surfaced by fuzz tester. (The test case that failed was the
one that's already hard coded.)
* In persistent mode, disable test that reads a ref
Refs behave differently in persistent mode. I added a TODO to write
a persistent mode version of this test.
* Run persistent mode tests in CI
* test-persistent should skip files without noop
If a file doesn't reference react-noop-renderer, we shouldn't bother
running it in persistent mode, since the results will be identical to
the normal test run.
* Remove module constructor from placeholder tests
We don't need this now that we have the ability to run any test file in
either mutation or persistent mode.
* Revert "test-persistent should skip files without noop"
Seb objected to adding shelljs as a dep and I'm too lazy to worry about
Windows support so whatever I'll just revert this.
* Delete duplicate file
* Convert ReactSuspensePlaceholder tests to use noop
Instead of the test renderer, since test renderer does not support
running in persistent mode.
* Run Placeholder tests in persistent mode, too
* Fix Flow and lint
* Hidden text instances should have correct host context
Adds a test for a subtle edge case that only occurs in persistent mode.
* createHiddenTextInstance -> cloneHiddenTextInstance
This sidesteps the problem where createHiddenTextInstance needs access
to the host context.
* Import Scheduler directly, not via host config
We currently schedule asynchronous tasks via the host config. (The host
config is a static/build-time dependency injection system that varies
across different renderers — DOM, native, test, and so on.) Instead of
calling platform APIs like `requestIdleCallback` directly, each renderer
implements a method called `scheduleDeferredCallback`.
We've since discovered that when scheduling tasks, it's crucial that
React work is placed in the same queue as other, non-React work on the
main thread. Otherwise, you easily end up in a starvation scenario where
rendering is constantly interrupted by less important tasks. You need a
centralized coordinator that is used both by React and by other
frameworks and application code. This coordinator must also have a
consistent API across all the different host environments, for
convention's sake and so product code is portable — e.g. so the same
component can work in both React Native and React Native Web.
This turned into the Scheduler package. We will have different builds of
Scheduler for each of our target platforms. With this approach, we treat
Scheduler like a built-in platform primitive that exists wherever React
is supported.
Now that we have this consistent interface, the indirection of the host
config no longer makes sense for the purpose of scheduling tasks. In
fact, we explicitly do not want renderers to scheduled task via any
system except the Scheduler package.
So, this PR removes `scheduleDeferredCallback` and its associated
methods from the host config in favor of directly importing Scheduler.
* Missed an extraneous export
* Replace noop's fake Scheduler implementation with mock Scheduler build
The noop renderer has its own mock implementation of the Scheduler
interface, with the ability to partially render work in tests. Now that
this functionality has been lifted into a proper mock Scheduler build,
we can use that instead.
Most of the existing noop tests were unaffected, but I did have to make
some changes. The biggest one involved passive effects: previously, they
were scheduled on a separate queue from the queue that handles
rendering. After this change, both rendering and effects are scheduled
in the Scheduler queue. I think this is a better approach because tests
no longer have to worry about the difference; if you call `flushAll`,
all the work is flushed, both rendering and effects. But for those few
tests that do care to flush the rendering without the effects, that's
still possible using the `yieldValue` API.
Follow-up: Do the same for test renderer.
* Fix import to scheduler/unstable_mock
* Throw in tests if work is done before emptying log
Test renderer already does this. Makes it harder to miss unexpected
behavior by forcing you to assert on every logged value.
* Convert ReactNoop tests to use jest matchers
The matchers warn if work is flushed while the log is empty. This is
the pattern we already follow for test renderer. I've used the same APIs
as test renderer, so it should be easy to switch between the two.
* Remove ReactNoop.flushDeferredPri and flushUnitsOfWork
Some of our older tests worked by counting how many times React checked
whether it should yield to the main thread, instead of something
publicly observable like how many times a component is rendered.
Our newer tests have converged on a style where we push into a log and
make assertions on the log. This pattern is less coupled to the
implementation while still being sufficient to test performance
optimizations, like resuming (whenever we add that back).
This commit removes flushDeferredPri and flushUnitsOfWork and upgrades
the affected tests.
* Remove shouldYieldToRenderer indirection
This wrapper is no longer necessary.
As I prepare to refactor the Fiber scheduler, I've noticed some quirks
in our implementation. This PR addressed one of them.
---
There's no reason for a timed out Scheduler callback to check
`shouldYield`, because the value will always be false until the work
has completed. The `didTimeout` argument provides this information to
the callback so it can avoid the redundant checks.
React's existing check for whether a callback has timed out didn't make
any sense, but happened to work anyway. I don't think the wrongness of
the old implementation is observable via React APIs but it's
incoherent regardless.
* expose unstable_interact for batching actions in tests
* move to TestUtils
* move it all into testutils
* s/interact/act
* warn when calling hook-like setState outside batching mode
* pass tests
* merge-temp
* move jsdom test to callsite
* mark failing tests
* pass most tests (except one)
* augh IE
* pass fuzz tests
* better warning, expose the right batchedUpdates on TestRenderer for www
* move it into hooks, test for dom
* expose a flag on the host config, move stuff around
* rename, pass flow
* pass flow... again
* tweak .act() type
* enable for all jest environments/renderers; pass (most) tests.
* pass all tests
* expose just the warning from the scheduler
* don't return values
* a bunch of changes.
can't return values from .act
don't try to await .act calls
pass tests
* fixes and nits
* "fire events that udpates state"
* nit
* 🙄
* my bad
* hi andrew
(prettier fix)
* Avoid importing Scheduler directly
The reconciler should not depend directly on Scheduler. This adds it to
the host config for the renderer instead.
(Except for `scheduler/tracing` imports, which are used only by the
profiling build. I've left those imports as-is, though I'm open to
directing those through the host config, too.)
* Make throwaway root id longer to appease Brian
Specifying the directory as part of the `repository` field in a `package.json`
allows third party tools to provide better support when working with monorepos.
For example, it allows them to correctly construct a commit diff for a specific
package.
This format was accepted by npm in https://github.com/npm/rfcs/pull/19.
* [Fizz] Add Flow/Jest/Rollup build infra
Add a new package for react-stream which allows for custom server renderer
outputs. I picked the name because it's a reasonable name but also
because the npm name is currently owned by a friend of the project.
The react-dom build has its own inlined server renderer under the
name `react-dom/fizz`.
There is also a noop renderer to be used for testing. At some point
we might add a public one to test-renderer but for now I don't want to have
to think about public API design for the tests.
* Add FormatConfig too
We need to separate the format (DOM, React Native, etc) from the host
running the server (Node, Browser, etc).
* Basic wiring between Node, Noop and DOM configs
The Node DOM API is pipeToNodeStream which accepts a writable stream.
* Merge host and format config in dynamic react-stream entry point
Simpler API this way but also avoids having to fork the wrapper config.
Fixes noop builds.
* Add setImmediate/Buffer globals to lint config
Used by the server renderer
* Properly include fizz.node.js
Also use forwarding to it from fizz.js in builds so that tests covers
this.
* Make react-stream private since we're not ready to publish
or even name it yet
* Rename Renderer -> Streamer
* Prefix react-dom/fizz with react-dom/unstable-fizz
* Add Fizz Browser host config
This lets Fizz render to WHATWG streams. E.g. for rendering in a
Service Worker.
I added react-dom/unstable-fizz.browser as the entry point for this.
Since we now have two configurations of DOM. I had to add another
inlinedHostConfigs configuration called `dom-browser`. The reconciler
treats this configuration the same as `dom`. For stream it checks
against the ReactFizzHostConfigBrowser instead of the Node one.
* Add Fizz Browser Fixture
This is for testing server rendering - on the client.
* Lower version number to detach it from react-reconciler version
Whenever we do this, Rollup needs to materialize this as an object.
This causes it to also add the Babel compatibility property which is
unnecessary bloat. However, since when we use these, we leak the object
this often also deopts any compiler optimizations.
If we really need an object we should export default an object.
Currently there is an exception for DOMTopLevelEventTypes since
listing out the imports is a PITA and it doesn't escape so it should
get properly inlined. We should probably move to a different pattern
to avoid this for consistency though.
* [scheduler] Deadline object -> shouldYield
Instead of using a requestIdleCallback-style deadline object, expose a
method Scheduler.shouldYield that returns true if there's a higher
priority event in the queue.
* Nits
