## Summary
swaps `react-test-renderer` for `react-noop-rendererer` in
ReactCacheOld-test
## How did you test this change?
`yarn test-www ReactCacheOld`
## Summary
Concurrent rendering has been the default since React 18 release.
ReactTestRenderer requires passing `{unstable_isConcurrent: true}` to
match this behavior, which means by default tests written with RTR use a
different rendering method than the code they test.
Eventually, RTR should only use ConcurrentRoot. As a first step, let's
add a version of the concurrent option that isn't marked unstable. Next
we will follow up with removing the unstable option when it is safe to
merge.
## How did you test this change?
`yarn test
packages/react-test-renderer/src/__tests__/ReactTestRendererAsync-test.js`
Many of our Suspense-related tests were written before the `act` API was
introduced, and use the lower level `waitFor` helpers instead. So they
are less resilient to changes in implementation details than they could
be.
This converts some of our test suite to use `act` in more places. I
found these while working on a PR to expand our fallback throttling
mechanism to include all renders that result from a promise resolving,
even if there are no more fallbacks in the tree.
I think this covers all the remaining tests that are affected.
Updates that are marked as part of a transition are allowed to block a
render from committing. Generally, other updates cannot — however,
there's one exception that's leftover from a previous iteration of our
Suspense architecture. If an update is not the result of a known urgent
event type — known as "Default" updates — then we allow it to suspend
briefly, as long as the delay is short enough that the user won't
notice. We refer to this delay as a "Just Noticable Difference" (JND)
delay. To illustrate, if the user has already waited 400ms for an update
to be reflected on the screen, the theory is that they won't notice if
you wait an additional 100ms. So React can suspend for a bit longer in
case more data comes in. The longer the user has already waited, the
longer the JND.
While we still believe this theory is sound from a UX perspective, we no
longer think the implementation complexity is worth it. The main thing
that's changed is how we handle Default updates. We used to render
Default updates concurrently (i.e. they were time sliced, and were
scheduled with postTask), but now they are blocking. Soon, they will
also be scheduled with rAF, too, which means by the end of the next rAF,
they will have either finished rendering or the main thread will be
blocked until they do. There are various motivations for this but part
of the rationale is that anything that can be made non-blocking should
be marked as a Transition, anyway, so it's not worth adding
implementation complexity to Default.
This commit removes the JND delay for Default updates. They will now
commit immediately once the render phase is complete, even if a
component suspends.
Today if something suspends, React will continue rendering the siblings
of that component.
Our original rationale for prerendering the siblings of a suspended
component was to initiate any lazy fetches that they might contain. This
was when we were more bullish about lazy fetching being a good idea some
of the time (when combined with prefetching), as opposed to our latest
thinking, which is that it's almost always a bad idea.
Another rationale for the original behavior was that the render was I/O
bound, anyway, so we might as do some extra work in the meantime. But
this was before we had the concept of instant loading states: when
navigating to a new screen, it's better to show a loading state as soon
as you can (often a skeleton UI), rather than delay the transition.
(There are still cases where we block the render, when a suitable
loading state is not available; it's just not _all_ cases where
something suspends.) So the biggest issue with our existing
implementation is that the prerendering of the siblings happens within
the same render pass as the one that suspended — _before_ the loading
state appears.
What we should do instead is immediately unwind the stack as soon as
something suspends, to unblock the loading state.
If we want to preserve the ability to prerender the siblings, what we
could do is schedule special render pass immediately after the fallback
is displayed. This is likely what we'll do in the future. However, in
the new implementation of `use`, there's another reason we don't
prerender siblings: so we can preserve the state of the stack when
something suspends, and resume where we left of when the promise
resolves without replaying the parents. The only way to do this
currently is to suspend the entire work loop. Fiber does not currently
support rendering multiple siblings in "parallel". Once you move onto
the next sibling, the stack of the previous sibling is discarded and
cannot be restored. We do plan to implement this feature, but it will
require a not-insignificant refactor.
Given that lazy data fetching is already bad for performance, the best
trade off for now seems to be to disable prerendering of siblings. This
gives us the best performance characteristics when you're following best
practices (i.e. hoist data fetches to Server Components or route
loaders), at the expense of making an already bad pattern a bit worse.
Later, when we implement resumable context stacks, we can reenable
sibling prerendering. Though even then the use case will mostly be to
prerender the CPU-bound work, not lazy fetches.
(This only affects our own internal repo; it's not a public API.)
I think most of us agree this is a less confusing name. It's possible
someone will confuse it with `console.log`. If that becomes a problem we
can warn in dev or something.
This converts some of our test suite to use the `waitFor` test pattern,
instead of the `expect(Scheduler).toFlushAndYield` pattern. Most of
these changes are automated with jscodeshift, with some slight manual
cleanup in certain cases.
See #26285 for full context.
I'm in the process of codemodding our test suite to the waitFor pattern.
See #26285 for full context.
This module required a lot of manual changes so I'm doing it as its own
PR. The reason is that most of the tests involved simulating an async
import by wrapping them in `Promise.resolve()`, which means they would
immediately resolve the next time the microtask queue was flushed. I
rewrote the tests to resolve the simulated import explicitly.
While converting these tests, I also realized that the `waitFor` helpers
weren't properly waiting for the entire microtask queue to recursively
finish — if a microtask schedules another microtask, the subsequent one
wouldn't fire until after `waitFor` had resolved. To fix this, I used
the same strategy as `act` — wait for a real task to finish before
proceeding, such as a message event.
This converts some of our test suite to use the `waitFor` test pattern,
instead of the `expect(Scheduler).toFlushAndYield` pattern. Most of
these changes are automated with jscodeshift, with some slight manual
cleanup in certain cases.
See #26285 for full context.
These suppressions are no longer required.
Generated using:
```sh
flow/tool update-suppressions .
```
followed by adding back 1 or 2 suppressions that were only triggered in
some configurations.
This setting is an incremental path to the next Flow version enforcing
type annotations on most functions (except some inline callbacks).
Used
```
node_modules/.bin/flow codemod annotate-functions-and-classes --write .
```
to add a majority of the types with some hand cleanup when for large
inferred objects that should just be `Fiber` or weird constructs
including `any`.
Suppressed the remaining issues.
Builds on #25918
* Facebook -> Meta in copyright
rg --files | xargs sed -i 's#Copyright (c) Facebook, Inc. and its affiliates.#Copyright (c) Meta Platforms, Inc. and affiliates.#g'
* Manual tweaks
- method unbinding is no longer supported in Flow for soundness, this added a bunch of suppressions
- Flow now prevents objects to be supertypes of interfaces/classes
ghstack-source-id: d7749cbad8
Pull Request resolved: https://github.com/facebook/react/pull/25412
This update range includes:
- `types_first` ([blog](https://flow.org/en/docs/lang/types-first/), all exports need annotated types) is default. I disabled this for now to make that change incremental.
- Generics that escape the scope they are defined in are an error. I fixed some with explicit type annotations and some are suppressed that I didn't easily figure out.
* Add .browser and .node explicit entry points
This can be useful when the automatic selection doesn't work properly.
* Remove react/index
I'm not sure why I added this in the first place. Perhaps due to how our
builds work somehow.
* Remove build-info.json from files field
* Hoist error codes import to module scope
When this code was written, the error codes map (`codes.json`) was
created on-the-fly, so we had to lazily require from inside the visitor.
Because `codes.json` is now checked into source, we can import it a
single time in module scope.
* Minify error constructors in production
We use a script to minify our error messages in production. Each message
is assigned an error code, defined in `scripts/error-codes/codes.json`.
Then our build script replaces the messages with a link to our
error decoder page, e.g. https://reactjs.org/docs/error-decoder.html/?invariant=92
This enables us to write helpful error messages without increasing the
bundle size.
Right now, the script only works for `invariant` calls. It does not work
if you throw an Error object. This is an old Facebookism that we don't
really need, other than the fact that our error minification script
relies on it.
So, I've updated the script to minify error constructors, too:
Input:
Error(`A ${adj} message that contains ${noun}`);
Output:
Error(formatProdErrorMessage(ERR_CODE, adj, noun));
It only works for constructors that are literally named Error, though we
could add support for other names, too.
As a next step, I will add a lint rule to enforce that errors written
this way must have a corresponding error code.
* Minify "no fallback UI specified" error in prod
This error message wasn't being minified because it doesn't use
invariant. The reason it didn't use invariant is because this particular
error is created without begin thrown — it doesn't need to be thrown
because it's located inside the error handling part of the runtime.
Now that the error minification script supports Error constructors, we
can minify it by assigning it a production error code in
`scripts/error-codes/codes.json`.
To support the use of Error constructors more generally, I will add a
lint rule that enforces each message has a corresponding error code.
* Lint rule to detect unminified errors
Adds a lint rule that detects when an Error constructor is used without
a corresponding production error code.
We already have this for `invariant`, but not for regular errors, i.e.
`throw new Error(msg)`. There's also nothing that enforces the use of
`invariant` besides convention.
There are some packages where we don't care to minify errors. These are
packages that run in environments where bundle size is not a concern,
like react-pg. I added an override in the ESLint config to ignore these.
* Temporarily add invariant codemod script
I'm adding this codemod to the repo temporarily, but I'll revert it
in the same PR. That way we don't have to check it in but it's still
accessible (via the PR) if we need it later.
* [Automated] Codemod invariant -> Error
This commit contains only automated changes:
npx jscodeshift -t scripts/codemod-invariant.js packages --ignore-pattern="node_modules/**/*"
yarn linc --fix
yarn prettier
I will do any manual touch ups in separate commits so they're easier
to review.
* Remove temporary codemod script
This reverts the codemod script and ESLint config I added temporarily
in order to perform the invariant codemod.
* Manual touch ups
A few manual changes I made after the codemod ran.
* Enable error code transform per package
Currently we're not consistent about which packages should have their
errors minified in production and which ones should.
This adds a field to the bundle configuration to control whether to
apply the transform. We should decide what the criteria is going
forward. I think it's probably a good idea to minify any package that
gets sent over the network. So yes to modules that run in the browser,
and no to modules that run on the server and during development only.
We added this unstable feature a few years ago, as a way to opt out of
context updates, but it didn't prove useful in practice.
We have other proposals for how to address the same problem, like
context selectors.
Since it was prefixed with `unstable_`, we should be able to remove it
without consequence. The hook API already warned if you used it.
Even if someone is using it somewhere, it's meant to be an optimization
only, so if they are using the API properly, it should not have any
semantic impact.
* Rename ReactCache -> ReactCacheOld
We still use it in some tests so I'm going to leave it for now. I'll start making the new one in parallel in the react package.
* Add react/unstable-cache entry point
* Add react-data entry point
* Initial implementation of cache and data/fetch
* Address review
* Disable console log during the second rerender
* Use the disabled log to avoid double yielding values in scheduler mock
* Reenable debugRenderPhaseSideEffectsForStrictMode in tests that can
* Enable prefer-const rule
Stylistically I don't like this but Closure Compiler takes advantage of
this information.
* Auto-fix lints
* Manually fix the remaining callsites
* Formalize the Wakeable and Thenable types
We use two subsets of Promises throughout React APIs. This introduces
the smallest subset - Wakeable. It's the thing that you can throw to
suspend. It's something that can ping.
I also use a shared type for Thenable in the cases where we expect a value
so we can be a bit more rigid with our us of them.
* Make Chunks into Wakeables instead of using native Promises
This value is just going from here to React so we can keep it a lighter
abstraction throughout.
* Renamed thenable to wakeable in variable names
* import * as React from "react";
This is the correct way to import React from an ES module since the ES
module will not have a default export. Only named exports.
* import * as ReactDOM from "react-dom"
* Update Flow to 0.84
* Fix violations
* Use inexact object syntax in files from fbsource
* Fix warning extraction to use a modern parser
* Codemod inexact objects to new syntax
* Tighten types that can be exact
* Revert unintentional formatting changes from codemod
* Replace all warning/lowPriWarning with console calls
* Replace console.warn/error with a custom wrapper at build time
* Fail the build for console.error/warn() where we can't read the stack
* prep for codemod
* prep warnings
* rename lint rules
* codemod for ifs
* shim www functions
* Handle more cases in the transform
* Thanks De Morgan
* Run the codemod
* Delete the transform
* Fix up confusing conditions manually
* Fix up www shims to match expected API
* Also check for low-pri warning in the lint rule
* Rewrite ReactFiberScheduler
Adds a new implementation of ReactFiberScheduler behind a feature flag.
We will maintain both implementations in parallel until the new one
is proven stable enough to replace the old one.
The main difference between the implementations is that the new one is
integrated with the Scheduler package's priority levels.
* Conditionally add fields to FiberRoot
Some fields only used by the old scheduler, and some by the new.
* Add separate build that enables new scheduler
* Re-enable skipped test
If synchronous updates are scheduled by a passive effect, that work
should be flushed synchronously, even if flushPassiveEffects is
called inside batchedUpdates.
* Passive effects have same priority as render
* Revert ability to cancel the current callback
React doesn't need this anyway because it never schedules callbacks if
it's already rendering.
* Revert change to FiberDebugPerf
Turns out this isn't neccessary.
* Fix ReactFiberScheduler dead code elimination
Should initialize to nothing, then assign the exports conditionally,
instead of initializing to the old exports and then reassigning to the
new ones.
* Don't yield before commit during sync error retry
* Call Scheduler.flushAll unconditionally in tests
Instead of wrapping in enableNewScheduler flag.
* Swap expect(ReactNoop) for expect(Scheduler)
In the previous commits, I upgraded our custom Jest matchers for the
noop and test renderers to use Scheduler under the hood.
Now that all these matchers are using Scheduler, we can drop
support for passing ReactNoop and test roots and always pass
Scheduler directly.
* Externalize Scheduler in noop and test bundles
I also noticed we don't need to regenerator runtime in noop anymore.
* Replace test renderer's fake Scheduler implementation with mock build
The test 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.
* Fix Profiler tests in prod
* Add Scheduler.unstable_next
* Use Scheduler to prioritize updates
Changes the implementation of syncUpdates, deferredUpdates, and
interactiveUpdates to use runWithPriority, so
This is the minimum integration between Scheduler and React needed to
unblock use of the Scheduler.next API.
* Add Scheduler.unstable_next
* Use Scheduler to prioritize updates
Changes the implementation of syncUpdates, deferredUpdates, and
interactiveUpdates to use runWithPriority, so
This is the minimum integration between Scheduler and React needed to
unblock use of the Scheduler.next API.
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.
* [react-cache] Remove `cache` as argument to `read`
Updated is API is `Resource.read(key)` instead of
`Resource.read(cache, key)`.
The cache is read from context using `readContext`.
This also removes cache invalidation entirely (other than the default
LRU mechanism), as well as the ability to have multiple caches. We'll
add it back once `Context.write` lands and we can implement it the
right way.
Since there's now only a single cache (the global one), we don't
actually need to use context yet, but I've added a dummy context
anyway so the user gets an error if they attempt to read outside the
render phase.
* nits
* Add test for thenables that resolve multiple times
