By default, React Compiler will skip compilation if it cannot preserve existing memoization. Ie, if the code has an existing `useMemo()` or `useCallback()` and the compiler cannot determine that it is safe to keep that memoization — or do even better — then we'll leave the code alone. The actual compilation doesn't use any hints from existing memo calls, this is purely to check and avoid regressing any specific memoization that developers may have already applied.
However, we were accidentally reporting some false-positive _validation_ errors due to the StartMemoize and FinishMemoize instructions that we emit to track where the memoization was in the source code. This is now fixed.
Fixes#29131Fixes#29132
ghstack-source-id: 9f6b8dbc50
Pull Request resolved: https://github.com/facebook/react/pull/29154
Improves ValidateNoRefAccessInRender (still disabled by default) to properly ignore ref access within effects. This includes allowing ref access within functions that are only transitively called from an effect.
While I was here I also added some extra test fixtures for allowing global mutation in effects.
ghstack-source-id: fb6352a178
Pull Request resolved: https://github.com/facebook/react/pull/29151
As a fellow beginner to React, I didn't even know React runs on top of
Node when I started.
So, some beginners might get confused about what is Node and how to find
details about it or how to download it.
So, I thought to add a hyperlink to Node replacing the word Node in the
README.md file. I think this might be a valuable contribution.
- Januda
## Summary
The "Good First Issues" header in the README was missing a hyperlink
where the other similar headlines had one.
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## How did you test this change?
N/A
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Babel doesn't seem to properly preserve escaping of HTML entities when emitting JSX text children, so this commit works around the issue by emitting a JsxExpressionContainer for JSX children that contain ">", "<", or "&" characters.
Closes#29100
ghstack-source-id: 2d0622397c
Pull Request resolved: https://github.com/facebook/react/pull/29143
## Summary
Every tab wraps the text around but there is no way to resize it. It was
also hard to use the source map tab. It doesn't occupy the full height
nor is the tab resizable. So I made all the tabs resizable.
> Also,
> * make the source map tab occupy full height
> * make it a teeny tiny bit easier to work with the compiler playground
(especially source map)
## How did you test this change?
https://github.com/facebook/react/assets/91976421/cdec30e8-cadb-4958-8786-31c54ea83bd6
Signed-off-by: abizek <abishekilango@protonmail.com>
Adds a GitHub issue template form so we can automatically categorize
issues and get more information upfront. I mostly referenced the
DevTools bug report template and made some tweaks.
ghstack-source-id: 5bfc728a62
Pull Request resolved: https://github.com/facebook/react/pull/29140
Workaround for a bug in older versions of Babel, where strings with unicode are incorrectly escaped when emitted as JSX attributes, causing double-escaping by later processing.
Closes#29120Closes#29124
ghstack-source-id: 065440d4fb
Pull Request resolved: https://github.com/facebook/react/pull/29141
Now that the compiler is public, the `*` version was grabbing the latest
version of the compiler off of npm and was resolving to my very first
push to npm (an empty package containing only a single package.json).
This was breaking the playground as it would attempt to load the
compiler but then crash the babel pipeline due to the node module not
being found.
ghstack-source-id: 695fd9caac
Pull Request resolved: https://github.com/facebook/react/pull/29122
@jbonta nerd-sniped me into making this optimization during conference
prep, posting this as a PR now that keynote is over.
Consider these two cases:
```javascript
export default function MyApp1({ count }) {
const cb = () => count;
return <div onclick={cb}>Hello World</div>;
}
export default function MyApp2({ count }) {
return <div onclick={() => count}>Hello World</div>;
}
```
Previously, the former would create two reactive scopes (one for `cb`,
one for the div) while the latter would only have a single scope for the
`div` and its inline callback. The reason we created separate scopes
before is that there's a `StoreLocal 'cb' = t0` instruction in-between,
and i had conservatively implemented the merging pass to not allow
intervening StoreLocal instructions.
The observation is that intervening StoreLocals are fine _if_ the
assigned variable's last usage is the next scope. We already have a
check that the intervening lvalues are last-used at/before the next
scope, so it's trivial to extend this to support StoreLocal.
Note that we already don't merge scopes if there are intervening
terminals, so we don't have to worry about things like conditional
StoreLocal, conditional access of the resulting value, etc.
/cc @poteto
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## Summary
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Seems like the README of the package was outdated.
## How did you test this change?
Tried this configuration in a project of mine.
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## Summary
Use `filename` instead of `context.filename` in eslint compiler.
The problem is that in `react-native` + `typescript` project the context
may not have `filename`:
<img width="384" alt="image"
src="https://github.com/facebook/react/assets/22820318/e5d184fa-5ac9-4512-96b9-644baa3d5f25">
And eslint will crash with:
```bash
TypeError: Error while loading rule 'react-compiler/react-compiler': Cannot read properties of undefined (reading 'endsWith')
```
But in fact we already derive `filename` variable earlier so we can
simply reuse the variable (I guess).
## How did you test this change?
- add `eslint` plugin to RN project;
- run eslint
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## Summary
This PR fixes a typo in `./compiler/docs/DESIGN_GOALS.md`.
I believe `plugion` should be `plugin`.
## How did you test this change?
Rendered the markdown to html.
This script needs to run from `main` since it commits version bumps for
packages, and those need to point to publicly available hashes. So,
throw an error if we're not already on main.
ghstack-source-id: ce0168e826
Pull Request resolved: https://github.com/facebook/react/pull/29083
- Specify a registry for npm publish because otherwise it tries to use
the yarn registry
- `packages` option actually works
This _should_ work now (note last line of output), will test it once we
land this since i want to publish a new version of the eslint plugin
with some important fixes.
```
npm notice
npm notice 📦 eslint-plugin-react-compiler@0.0.0-experimental-53bb89e-20240515
npm notice === Tarball Contents ===
npm notice 827B README.md
npm notice 2.1MB dist/index.js
npm notice 1.0kB package.json
npm notice === Tarball Details ===
npm notice name: eslint-plugin-react-compiler
npm notice version: 0.0.0-experimental-53bb89e-20240515
npm notice filename: eslint-plugin-react-compiler-0.0.0-experimental-53bb89e-20240515.tgz
npm notice package size: 300.9 kB
npm notice unpacked size: 2.1 MB
npm notice shasum: cb99823f3a483c74f470085cac177bd020f7a85a
npm notice integrity: sha512-L3HV9qja1dnCl[...]IaRSZJ3P/v6yQ==
npm notice total files: 3
npm notice
npm notice Publishing to http://registry.npmjs.org/ with tag latest and default access (dry-run)
```
ghstack-source-id: 63067ef772
Pull Request resolved: https://github.com/facebook/react/pull/29082
Previously we would attempt to parse code in the eslint plugin with the
HermesParser first as it can handle some TS syntax. However, this was
leading to a mis-parse of React hook calls with type params (eg,
`useRef<null>()` as a BinaryExpression rather than a CallExpression with
a type param. This triggered our validation that Hooks should not be
used as normal values.
To fix this, we now try to parse with the babel parser (with TS support)
for filenames that end with ts/tsx, and fallback to HermesParser for
regular JS files.
ghstack-source-id: 5b7231031c
Pull Request resolved: https://github.com/facebook/react/pull/29081
Previously, we only checked for StrictMode by searching for
`<StrictMode>` but we should also check for the namespaced version,
`<React.StrictMode>`.
Fixes https://github.com/facebook/react/issues/29075
Fixes the top-level ESLint and Prettier configs to ignore the compiler.
For now the compiler has its own prettier and linting setup with
different versions/configs.
## Summary
The main field is missing, this fixes it.
Fixes#29068.
## How did you test this change?
Manually patched the package and tried it in my codebase.
This updates the Canary label from "beta" to "rc".
We will publish an actual RC (e.g. 19.0.0-rc.0) too; this only changes
the label in the canary releases.
Herrington Darkholme
Joe Savona
Januda Bethmin
NickeSteenen
Risto Keravuori
Lauren Tan
Abishek Ilango
mofeiZ
Sebastian Markbåge
Joseph Savona
Yuta Sakou
Jason Bonta
Jan Amann
Kirill Zyusko
Steven
Sathya Gunasekaran
Christoph Nakazawa
Andrew Clark