We only need the compiler built for `yarn test` in the root directory.
Rather than always cache both for every step, let's just do it where
it's needed explicitly.
Now that the compiler lint rule is merged into
eslint-plugin-react-hooks, we also need to update our caches so compiler
dependencies are also cached. This should fix the CI walltime regression
we are now seeing.
---
[//]: # (BEGIN SAPLING FOOTER)
Stack created with [Sapling](https://sapling-scm.com). Best reviewed
with [ReviewStack](https://reviewstack.dev/facebook/react/pull/32603).
* #32604
* __->__ #32603
Removes `EnvironmentConfig.enableMinimalTransformsForRetry` in favor of
`run` parameters. This is a minimal difference but lets us explicitly
opt out certain compiler passes based on mode parameters, instead of
environment configurations
Retry flags don't really make sense to have in `EnvironmentConfig`
anyways as the config is user-facing API, while retrying is a compiler
implementation detail.
(per @josephsavona's feedback
https://github.com/facebook/react/pull/32164#issuecomment-2608616479)
> Re the "hacky" framing of this in the PR title: I think this is fine.
I can see having something like a compilation or output mode that we use
when running the pipeline. Rather than changing environment settings
when we re-run, various passes could take effect based on the
combination of the mode + env flags. The modes might be:
>
> * Full: transform, validate, memoize. This is the default today.
> * Transform: Along the lines of the backup mode in this PR. Only
applies transforms that do not require following the rules of React,
like `fire()`.
> * Validate: This could be used for ESLint.
---
[//]: # (BEGIN SAPLING FOOTER)
Stack created with [Sapling](https://sapling-scm.com). Best reviewed
with [ReviewStack](https://reviewstack.dev/facebook/react/pull/32511).
* #32512
* __->__ #32511
This change fixes a coverage hole in rolling out with `gating`. Prior to
this PR, configuring `gating` causes React Compiler to bail out of
optimizing some functions.
This means that it's not entirely safe to cutover from `gating` enabled
for all users (i.e. rolled out 100%) to removing the `gating` config
altogether, as new functions may be opted into compilation when they
stop bailing out due to gating-specific logic.
This is technically slightly slower due to the additional function
indirection. An alternative approach is to recommend running a codemod
to insert `use no memo`s on currently-bailing out functions before
removing the`gating` config.
---
Tested [internally](
https://fburl.com/diff/q982ovua) by enabling on a page that previously
had a few hundred bailouts due to gating + hoisted function declarations
and (1) clicking around locally and (2) running a bunch of e2e tests
Reduce false positive bailouts by using the same
`isReferencedIdentifier` logic that the compiler also uses for
determining context variables and a function's own hoisted declarations.
Details:
Previously, we counted every babel identifier as a reference. This is
problematic because babel counts most string symbols as an identifier.
```js
print(x); // x is an identifier as expected
obj.x // x is.. also an identifier here
{x: 2} // x is also an identifier here
```
This PR adds a check for `isReferencedIdentifier`. Note that only
non-lval
references pass this check. This should be fine as we don't need to
hoist function declarations before writes to the same lvalue (which
should error in strict mode anyways)
```js
print(x); // isReferencedIdentifier(x) -> true
obj.x // isReferencedIdentifier(x) -> false
{x: 2} // isReferencedIdentifier(x) -> false
x = 2 // isReferencedIdentifier(x) -> false
```
---
[//]: # (BEGIN SAPLING FOOTER)
Stack created with [Sapling](https://sapling-scm.com). Best reviewed
with [ReviewStack](https://reviewstack.dev/facebook/react/pull/32596).
* __->__ #32596
* #32595
* #32594
* #32593
* #32522
* #32521
- Add `at`, `indexOf`, and `includes`
- Optimize MixedReadOnly which is currently only used by hook return
values. Hook return values are typed as Frozen, this change propagates
that to return values of aliasing function calls (such as `at`). One
potential issue is that developers may pass
`enableAssumeHooksFollowRulesOfReact:false` and set
`transitiveMixedData`, expecting their transitive mixed data to be
mutable. This is a bit of an edge case and already doesn't have clear
semantics.
---
[//]: # (BEGIN SAPLING FOOTER)
Stack created with [Sapling](https://sapling-scm.com). Best reviewed
with [ReviewStack](https://reviewstack.dev/facebook/react/pull/32594).
* #32596
* #32595
* __->__ #32594
* #32593
* #32522
* #32521
Expand type inference to infer mixedReadOnly types for numeric and
computed property accesses.
```js
function Component({idx})
const data = useFragment(...)
// we want to type `posts` correctly as Array
const posts = data.viewers[idx].posts.slice(0, 5);
// ...
}
```
---
[//]: # (BEGIN SAPLING FOOTER)
Stack created with [Sapling](https://sapling-scm.com). Best reviewed
with [ReviewStack](https://reviewstack.dev/facebook/react/pull/32593).
* #32596
* #32595
* #32594
* __->__ #32593
* #32522
* #32521
## Summary
Right now, `react-compiler-healthcheck` flags `mobx` as a "known
incompatible library". But it's not precisely *MobX* that's
incompatible. It's the observer HOC that comes from `mobx-react` and
`mobx-react-lite`.
I've been working on
[mst-use-observable](https://github.com/coolsoftwaretyler/mst-use-observable),
which makes MobX-State-Tree compatible with the compiler. However,
projects that use `mobx-state-tree` and `mst-use-observable` will still
depend on `mobx` as a dependency.
And there [have been efforts in the past to write a hook for
observability](https://github.com/mobxjs/mobx/discussions/2566). So it's
possible that MobX could become compatible, so long as authors access it
with a hook, rather than the HOC.
I would like to propose updating the health check to be a little more
precise and flag the HOC dependencies, rather than MobX itself.
Thanks in advance for your consideration!
## How did you test this change?
`npx react-compiler-healthcheck` shouldn't flag on `mobx` in
dependencies, but will for `mobx-react-lite` and `mobx-react`.
Test suites, formatting, linting, all passed.
---------
Co-authored-by: lauren <poteto@users.noreply.github.com>
fix: update CONTRIBUTING.md link path
Updated the relative path to CONTRIBUTING.md from `../CONTRIBUTING.md`
to `./../../CONTRIBUTING.md` to ensure the correct file is referenced.
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## Summary
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## How did you test this change?
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This change merges the `react-compiler` rule from
`eslint-plugin-react-compiler` into the `eslint-plugin-react-hooks`
plugin. In order to do the move in a way that keeps commit history with
the moved files, but also no remove them from their origin until a
future cleanup change can be done, I did the `git mv` first, and then
recreated the files that were moved in their original places, as a
separate commit. Unfortunately GH shows the moved files as new instead
of the ones that are truly new. But in the IDE and `git blame`, commit
history is intact with the moved files.
Since this change adds new dependencies, and one of those dependencies
has a higher `engines` declaration for `node` than what the plugin
currently has, this is technically a breaking change and will have to go
out as part of a major release.
### Related Changes
- https://github.com/facebook/react/pull/32458
---------
Co-authored-by: Lauren Tan <poteto@users.noreply.github.com>
This adds a page to the DOM fixture to test Fragment Refs. The first
test case is for `addEventListener`/`removeEventListener`.
Setting `enableFragmentRefs` to `__EXPERIMENTAL__` and building is
required to run the fixture.
<img width="872" alt="Screenshot 2025-03-05 at 12 58 57 PM"
src="https://github.com/user-attachments/assets/fee498b7-fd96-4178-9e82-c46d4cb55c9b"
/>
I'm not sure what exactly is causing the flakiness in the playground e2e
tests but I suspect it's some kind of timing issue.
Let's try waiting for Monaco to be fully initialized before running
tests.
---
[//]: # (BEGIN SAPLING FOOTER)
Stack created with [Sapling](https://sapling-scm.com). Best reviewed
with [ReviewStack](https://reviewstack.dev/facebook/react/pull/32584).
* __->__ #32584
* #32583
Extracting portions of #32416 for easier review. This PR dedupes
@babel/types to resolve to 7.26.3, for compatibility in the root
workspace where eslint-plugin-react-hooks resides.
I also needed to update @babel/preset-typescript in snap.
The compiler changes in HIR and ReactiveScopes were needed due to types
changing. Notably, Babel [added support for optional chaining
assignment](https://github.com/babel/babel/pull/15751) (currently [Stage
1](https://github.com/tc39/proposal-optional-chaining-assignment)), so
in the latest versions of @babel/types, AssignmentExpression.left can
now also be of t.OptionalMemberExpression.
Given that this is in Stage 1, the compiler probably shouldn't support
this syntax, so this PR updates HIR to bailout with a TODO if there is a
non LVal on the lhs of an Assignment Expression.
There was also a small superficial SourceLocation change needed in
`InferReactiveScopeVariables` as Babel 8 changes were [accidentally
released in
7](https://github.com/babel/babel/issues/10746#issuecomment-2699146670).
It doesn't affect our analysis so it seems fine to just update with the
new properties.
---
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* #32582
* __->__ #32581
Co-authored-by: michael faith <michaelfaith@users.noreply.github.com>
Co-authored-by: michael faith <michaelfaith@users.noreply.github.com>
Follow up to #32540.
We do allow gestures to be cancelled early (we call skipTransition) if
the gesture stops before it has even started.
This happens in the fixture when we auto-scroll.
*This API is experimental and subject to change or removal.*
This PR is an alternative to
https://github.com/facebook/react/pull/32421 based on feedback:
https://github.com/facebook/react/pull/32421#pullrequestreview-2625382015
. The difference here is that we traverse from the Fragment's fiber at
operation time instead of keeping a set of children on the
`FragmentInstance`. We still need to handle newly added or removed child
nodes to apply event listeners and observers, so we treat those updates
as effects.
**Fragment Refs**
This PR extends React's Fragment component to accept a `ref` prop. The
Fragment's ref will attach to a custom host instance, which will provide
an Element-like API for working with the Fragment's host parent and host
children.
Here I've implemented `addEventListener`, `removeEventListener`, and
`focus` to get started but we'll be iterating on this by adding
additional APIs in future PRs. This sets up the mechanism to attach refs
and perform operations on children. The FragmentInstance is implemented
in `react-dom` here but is planned for Fabric as well.
The API works by targeting the first level of host children and proxying
Element-like APIs to allow developers to manage groups of elements or
elements that cannot be easily accessed such as from a third-party
library or deep in a tree of Functional Component wrappers.
```javascript
import {Fragment, useRef} from 'react';
const fragmentRef = useRef(null);
<Fragment ref={fragmentRef}>
<div id="A" />
<Wrapper>
<div id="B">
<div id="C" />
</div>
</Wrapper>
<div id="D" />
</Fragment>
```
In this case, calling `fragmentRef.current.addEventListener()` would
apply an event listener to `A`, `B`, and `D`. `C` is skipped because it
is nested under the first level of Host Component. If another Host
Component was appended as a sibling to `A`, `B`, or `D`, the event
listener would be applied to that element as well and any other APIs
would also affect the newly added child.
This is an implementation of the basic feature as a starting point for
feedback and further iteration.
This fixes a critical issue with moveBefore. I was told that the
disconnected -> connected case was going to be relaxed and not be an
error but apparently that is not the case.
This means that we can't use this for initial insertions. Only moves.
Unfortunately React's internals doesn't distinguish these cases. This
adds a hack that checks each nodes but this is pretty bad for
performance. We should only call this in one or the other case.
Given that we still need feature detection. Both of which means that
these calls are no longer inlined and this extra code. I wonder if it's
even worth it given that you can't even rely on it working anyway since
not all browsers have it. Kind of don't want to ship this until all
browsers have it.
Even then we'd ideally refactor React to use separate code paths for
initial insertion vs moves. Which leads to some unfortunate code
duplication.
Enabling feature detection of early DOM features in a framework is
reckless. I'm not judging other frameworks (but also a little bit).
Because if you do something like `if (moveBefore) moveBefore(a, b) else
insertBefore(a, b)` like we do and then the implementation has to change
there are still too many websites out there that it becomes impossible
to change it. It would break the web. It would instead have to change to
a different name. That's what happened with `contains` -> `includes`.
Counter to popular belief it didn't have anything to do with patching
prototypes. Therefore, ideally frameworks shouldn't start rely on it
until there's two implementations so that there's time for feedback.
That's why we didn't immediately enable this even in experimental.
However, at this point there's probably enough feature detection and it
has shipped long enough in Chrome that it's unlikely to be able to
change at this point.
We can enable it now. For now just in `@experimental` to see if we can
flush out issues with it before bringing it to stable.
Otherwise these can survive into the next View Transition and cause
havoc to that transition.
This was appearing as a flash in Safari in the fixture when going from
A->B. This triggers a View Transition and at the same time the scroll
position updates in an effect. That fires a scroll event which starts a
gesture. This shouldn't really happen and the SwipeRecognizer should
ideally ignore those but it's good to surface edge cases. That gesture
is blocked on the View Transition finishing and then immediately after
it starts a gesture View Transition. That gesture then picked up the
former Animation from the previous transition which caused issues. This
PR fixes that flash.
Currently in the `compiler` workspace, we invoke esbuild directly to
build most packages (with the exception of `snap`). This has been mostly
fine, but does not allow us to do things like generate type declaration
files.
I would like #32416 to be able to consume the merged
eslint-plugin-react-compiler from source rather than via npm, and one of
the things that has come up from my exploration in that stack using the
compiler from source is that babel-plugin-react-compiler is missing type
declarations. This is primarily because React's build process uses
rollup + rollup-plugin-typescript, which runs tsc. So the merged plugin
needs to typecheck properly in order to build. An alternative might be
to migrate to something like babel with rollup instead to simply strip
types rather than typecheck before building. The minor downside of that
approach is that we would need to manually maintain a d.ts file for
eslint-plugin-react-hooks. For now I would like to see if this PR helps
us make progress rather than go for the slightly worse alternative.
[`tsup`](https://github.com/egoist/tsup) is esbuild based so build
performance is comparable. It is slower when generating d.ts files, but
it's still much faster than rollup which we used prior to esbuild. For
now, I have turned off `dts` by default, and it is only passed when
publishing on npm.
If you want to also generate d.ts files you can run `yarn build --dts`.
```
# BEFORE: build all compiler packages (esbuild)
$ time yarn build
✨ Done in 15.61s.
yarn build 13.82s user 1.54s system 96% cpu 15.842 total
# ---
# AFTER: build all compiler packages (tsup)
$ time yarn build
✨ Done in 12.39s.
yarn build 12.58s user 1.68s system 106% cpu 13.350 total
# ---
# AFTER: build all compiler packages and type declarations (tsup)
$ time yarn build --dts
✨ Done in 30.69s.
yarn build 43.57s user 3.20s system 150% cpu 31.061 total
```
I still need to test if this unblocks #32416 but this stack can be
landed independently though as we could probably just release type
declarations on npm. No one should be using the compiler directly, but
if they really wanted to, lack of type declarations would not stop them
(cf React secret internals).
Note that I still kept esbuild as we still use it directly for forgive.
---
[//]: # (BEGIN SAPLING FOOTER)
Stack created with [Sapling](https://sapling-scm.com). Best reviewed
with [ReviewStack](https://reviewstack.dev/facebook/react/pull/32550).
* #32551
* __->__ #32550
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## Summary
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This PR fixes asserts when `passChildrenWhenCloningPersistedNodes` is
enabled for React Native and OffscreenComponent child rendering unhides
host components.
Discussions around possible fixes for the asserts seen in React Native
suggested changing the way we handle hiding/unhiding host components by
updating the fiber state with the hidden host component instead of
submitting a hidden clone Fabric and keeping the original as the current
fiber.
Implementing this fix would require holding onto the original styling of
the hidden host component. The reconciler updates the styling by adding
`display: none` to hide the contents. If the original host component was
already hidden, the renderer would lose that information and remove the
styling when showing the contents again.
To reduce the changes required to make
`passChildrenWhenCloningPersistedNodes` work, this PR falls back to the
original cloning method when OffscreenComponents are part of the
children needed to be added back. This effectively resolve the asserts
triggered by the feature in RN and improves overall performance.
## How did you test this change?
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This fix was tested by enabling `passChildrenWhenCloningPersistedNodes`
in an app built with React Native that had a repro for triggering the
asserts. The asserts do not occur anymore when using the changes in this
PR.
---------
Co-authored-by: Nick <lefever@meta.com>
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Adds changelog entries for the last two minor releases of
`eslint-plugin-react-hooks`. Fixes#31717.
I chose to not include #31208 (8382581446)
and #32115 (fd2d279984) in the changelog
as they only changed internals that do not affect consumers of the
plugin, and it doesn't seem like the changelog previously included such
changes.
Changes are sorted by importance (rather than by commit date), with the
most important changes first.
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Docs only, nothing to test.
This is used to register Server References that exist in the current
environment but also exists in the server it might call into. Such as a
remote server.
If the value comes from the remote server in the first place then this
is called automatically to ensure that you can pass a reference back to
where it came from - even if the `serverModuleMap` option is used. This
was already the case when `serverModuleMap` wasn't passed. This is how
you can pass server references back to the server. However, when we
added `serverModuleMap` that pass was skipped because we were getting
real functions instead of proxies.
For functions that wasn't yet passed from the remote server to the
current server, we can register them eagerly just like we do for
`import('/server').registerServerReference()`. You can now also do this
with `import('/client').registerServerReference()`. We could make them
shared so you only have to do this once but it might not be possible to
pass to the remote server and the remote server might not even be the
same RSC renderer. Therefore I split them. It's up to the compiler
whether it should do that or not. It has to know that any function you
might call might be able to receive it. This is currently global to a
specific RSC renderer.
Setting the animation's currentTime causes a quirk where the transition
can end up off by a bit and the end state can be slightly off the end
time.
However, I realized that we don't have to because if we just set the
direction in the `animate()` call directly the Safari bug goes away.
Lauren Tan
mofeiZ
Tyler Scott Williams
Mohhamad Hussain
michael faith
Jack Pope
Sebastian Markbåge
Hendrik Liebau
Nick Lefever
Ricky
Mathias Stang
Sebastian "Sebbie" Silbermann
Keith Cirkel