Squashed, review-friendly version of the stack from
https://github.com/facebook/react/pull/33488.
This is new version of our mutability and inference model, designed to
replace the core algorithm for determining the sets of instructions
involved in constructing a given value or set of values. The new model
replaces InferReferenceEffects, InferMutableRanges (and all of its
subcomponents), and parts of AnalyzeFunctions. The new model does not
use per-Place effect values, but in order to make this drop-in the end
_result_ of the inference adds these per-Place effects.
I'll write up a larger document on the model, first i'm doing some
housekeeping to rebase the PR.
---
[//]: # (BEGIN SAPLING FOOTER)
Stack created with [Sapling](https://sapling-scm.com). Best reviewed
with [ReviewStack](https://reviewstack.dev/facebook/react/pull/33494).
* #33571
* #33558
* #33547
* #33543
* #33533
* #33532
* #33530
* #33526
* #33522
* #33518
* #33514
* #33513
* #33512
* #33504
* #33500
* #33497
* #33496
* #33495
* __->__ #33494
* #33572
React Compiler's program traversal logic is pretty lengthy and complex
as we've added a lot of features piecemeal. `compileProgram` is 300+
lines long and has confusing control flow (defining helpers inline,
invoking visitors, mutating-asts-while-iterating, mutating global
`ALREADY_COMPILED` state).
- Moved more stuff to `ProgramContext`
- Separated `compileProgram` into a bunch of helpers
Tested by syncing this stack to a Meta codebase and observing no
compilation output changes (D74487851, P1806855669, P1806855379)
---
[//]: # (BEGIN SAPLING FOOTER)
Stack created with [Sapling](https://sapling-scm.com). Best reviewed
with [ReviewStack](https://reviewstack.dev/facebook/react/pull/33147).
* #33149
* #33148
* __->__ #33147
(Almost) all pragmas are now one of the following:
- `@...TestOnly`: custom pragma for test fixtures
- `@<configName>` | `@<configName>:true`: enables with either true or a
default enabled value
- `@<configName>:<json value>`
This revisits a validation I built a while ago, trying to make it more strict this time to ensure that it's high-signal.
We detect function expressions which are *known* mutable — they definitely can modify a variable defined outside of the function expression itself (modulo control flow). This uses types to look for known Store and Mutate effects only, and disregards mutations of effects. Any such function passed to a location with a Freeze effect is reported as a validation error.
This is behind a flag and disabled by default. If folks agree this makes sense to revisit, i'll test out internally and we can consider enabling by default.
ghstack-source-id: 075a731444
Pull Request resolved: https://github.com/facebook/react/pull/33079
Previously the CompileSuccess event would emit first before CompileSkip,
so the lsp's codelens would incorrectly flag skipped components/hooks
(via 'use no memo') as being optimized.
---
[//]: # (BEGIN SAPLING FOOTER)
Stack created with [Sapling](https://sapling-scm.com). Best reviewed
with [ReviewStack](https://reviewstack.dev/facebook/react/pull/33012).
* __->__ #33012
* #33011
* #33010
Adds a new codeaction event in the compiler and handler in forgive. This
allows you to remove a dependency array when you're editing a range that
is within an autodep eligible function.
Co-authored-by: Jordan Brown <jmbrown@meta.com>
---
[//]: # (BEGIN SAPLING FOOTER)
Stack created with [Sapling](https://sapling-scm.com). Best reviewed
with [ReviewStack](https://reviewstack.dev/facebook/react/pull/33000).
* #33002
* #33001
* __->__ #33000
Co-authored-by: Jordan Brown <jmbrown@meta.com>
Currently, inferred effect dependencies are considered a
"compiler-required" feature. This means that untransformed callsites
should escalate to a build error.
`ValidateNoUntransformedReferences` iterates 'special effect' callsites
and checks that the compiler was able to successfully transform them.
Prior to this PR, this relied on checking the number of arguments passed
to this special effect.
This obviously doesn't work with `noEmit: true`, which is used for our
eslint plugin (this avoids mutating the babel program as other linters
run with the same ast). This PR adds a set of `babel.SourceLocation`s to
do best effort matching in this mode.
Avoid failing builds when imported function specifiers conflict by using
babel's `generateUid`. Failing a build is very disruptive, as it usually
presents to developers similar to a javascript parse error.
```js
import {logRender as _logRender} from 'instrument-runtime';
const logRender = () => { /* local conflicting implementation */ }
function Component_optimized() {
_logRender(); // inserted by compiler
}
```
Currently, we fail builds (even in `panicThreshold:none` cases) when
import specifiers are detected to conflict with existing local
variables. The reason we destructively throw (instead of bailing out) is
because (1) we first generate identifier references to the conflicting
name in compiled functions, (2) replaced original functions with
compiled functions, and then (3) finally check for conflicts.
When we finally check for conflicts, it's too late to bail out.
```js
// import {logRender} from 'instrument-runtime';
const logRender = () => { /* local conflicting implementation */ }
function Component_optimized() {
logRender(); // inserted by compiler
}
```
Updates ~all of our validations to return a Result, and then updates callers to either unwrap() if they should bailout or else just log.
ghstack-source-id: 418b5f5aa2
Pull Request resolved: https://github.com/facebook/react/pull/32688
React uses function identity to determine whether a given JSX expression represents the same type of component and should reconcile (keep state, update props) or replace (teardown state, create a new instance). This PR adds off-by-default validation to check that developers are not dynamically creating components during render.
The check is local and intentionally conservative. We specifically look for the results of call expressions, new expressions, or function expressions that are then used directly (or aliased) as a JSX tag. This allows common sketchy but fine-in-practice cases like passing a reference to a component from a parent as props, but catches very obvious mistakes such as:
```js
function Example() {
const Component = createComponent();
return <Component />;
}
```
We could expand this to catch more cases, but this seems like a reasonable starting point. Note that I tried enabling the validation by default and the only fixtures that error are the new ones added here. I'll also test this internally. What i'm imagining is that we enable this in the linter but not the compiler.
ghstack-source-id: e7408c0a55
Pull Request resolved: https://github.com/facebook/react/pull/32683
Traverse program after running compiler transform to find untransformed
references to compiler features (e.g. `inferEffectDeps`, `fire`).
Hard error to fail the babel pipeline when the compiler fails to
transform these features to give predictable runtime semantics.
Untransformed calls to functions like `fire` will throw at runtime
anyways, so let's fail the build to catch these earlier.
Note that with this fails the build *regardless of panicThreshold*
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
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
Adds a new Timing logger event to the compiler which currently only
records the walltime of running the compiler from the time the babel
plugin's Program visitor enters to the time it exits.
To enable, run the compiler with `ENABLE_REACT_COMPILER_TIMINGS=1 ...`
or `export ENABLE_REACT_COMPILER_TIMINGS=1` to set it by default.
Hacky retry pipeline for when transforming `fire(...)` calls encounters
validation, todo, or memoization invariant bailouts. Would love feedback
on how we implement this to be extensible to other compiler
non-memoization features (e.g. inlineJSX)
Some observations:
- Compiler "front-end" passes (e.g. lower, type, effect, and mutability
inferences) should be shared for all compiler features -- memo and
otherwise
- Many passes (anything dealing with reactive scope ranges, scope blocks
/ dependencies, and optimizations such as ReactiveIR #31974) can be left
out of the retry pipeline. This PR hackily skips memoization features by
removing reactive scope creation, but we probably should restructure the
pipeline to skip these entirely on a retry
- We should maintain a canonical set of "validation flags"
Note the newly added fixtures are prefixed with `bailout-...` when the
retry fire pipeline is used. These fixture outputs contain correctly
inserted `useFire` calls and no memoization.
For now we just reject all calls of impure functions, and the validation
is off by default. Going forward we can make this more precise and only
reject impure functions called during render.
Note that I was intentionally imprecise in the return type of these
functions in order to avoid changing output of existing code. We lie to
the compiler and say that Date.now, performance.now, and Math.random
return unknown mutable objects rather than primitives. Once the
validation is complete and vetted we can switch this to be more precise.
Traverse the compiled functions to ensure there are no lingering fires
and that all
fire calls are inside an effect lambda.
Also corrects the import to import from the compiler runtime instead
--
This is the diff with the meaningful changes. The approach is:
1. Collect fire callees and remove fire() calls, create a new binding
for the useFire result
2. Update LoadLocals for captured callees to point to the useFire result
3. Update function context to reference useFire results
4. Insert useFire calls after getting to the component scope
This approach aims to minimize the amount of new bindings we introduce
for the function expressions
to minimize bookkeeping for dependency arrays. We keep all of the
LoadLocals leading up to function
calls as they are and insert new instructions to load the originally
captured function, call useFire,
and store the result in a new promoted temporary. The lvalues that
referenced the original callee are
changed to point to the new useFire result.
This is the minimal diff to implement the expected behavior (up to
importing the useFire call, next diff)
and further stacked diffs implement error handling. The rules for fire
are:
1. If you use fire for a callee in the effect once you must use it for
every time you call it in that effect
2. You can only use fire in a useEffect lambda/functions defined inside
the useEffect lambda
There is still more work to do here, like updating the effect dependency
array and handling object methods
--
---
[//]: # (BEGIN SAPLING FOOTER)
Stack created with [Sapling](https://sapling-scm.com). Best reviewed
with [ReviewStack](https://reviewstack.dev/facebook/react/pull/31796).
* #31811
* #31798
* #31797
* __->__ #31796
Compiler playground now runs the entire program through
`babel-plugin-react-compiler` instead of a custom pipeline which
previously duplicated function inference logic from `Program.ts`. In
addition, the playground output reflects the tranformed file (instead of
a "virtual file" of manually concatenated functions).
This helps with the following:
- Reduce potential discrepencies between playground and babel plugin
behavior. See attached fixture output for an example where we previously
diverged.
- Let playground users see compiler-inserted imports (e.g. `_c` or
`useFire`)
This also helps us repurpose playground into a more general tool for
compiler-users instead of just for compiler engineers.
- imports and other functions are preserved.
We differentiate between imports and globals in many cases (e.g.
`inferEffectDeps`), so it may be misleading to omit imports in printed
output
- playground now shows other program-changing behavior like position of
outlined functions and hoisted declarations
- emitted compiled functions do not need synthetic names
---
[//]: # (BEGIN SAPLING FOOTER)
Stack created with [Sapling](https://sapling-scm.com). Best reviewed
with [ReviewStack](https://reviewstack.dev/facebook/react/pull/31774).
* #31809
* __->__ #31774
Adds `target: 'donotuse_meta_internal'`, which inserts useMemoCache
imports directly from `react`. Note that this is only valid for Meta
bundles, as others do not [re-export the `c`
function](https://github.com/facebook/react/blob/5b0ef217ef32333a8e56f39be04327c89efa346f/packages/react/index.fb.js#L68-L70).
```js
// target=donotuse_meta_internal
import {c as _c} from 'react';
// target=19
import {c as _c} from 'react/compiler-runtime';
// target=17,18
import {c as _c} from 'react-compiler-runtime';
```
Meta is a bit special in that react runtime and compiler are guaranteed
to be up-to-date and compatible. It also has its own bundling and module
resolution logic, which makes importing from `react/compiler-runtime`
tricky.
I'm also fine with implementing the alternative which adds an internal
stub for `react-compiler-runtime` and
[bundles](https://github.com/facebook/react/blob/5b0ef217ef32333a8e56f39be04327c89efa346f/scripts/rollup/bundles.js#L120)
the runtime for internal builds.
Adds a way to configure how we insert deps for experimental purposes.
```
[
{
module: 'react',
imported: 'useEffect',
numRequiredArgs: 1,
},
{
module: 'MyExperimentalEffectHooks',
imported: 'useExperimentalEffect',
numRequiredArgs: 2,
},
]
```
would insert dependencies for calls of `useEffect` imported from `react`
if they have 1 argument and calls of useExperimentalEffect` from
`MyExperimentalEffectHooks` if they have 2 arguments. The pushed dep
array is appended to the arg list.
This is for researching/prototyping, not a feature we are releasing
imminently.
Putting up an early version of inferring effect dependencies to get
feedback on the approach. We do not plan to ship this as-is, and may not
start by going after direct `useEffect` calls. Until we make that
decision, the heuristic I use to detect when to insert effect deps will
suffice for testing.
The approach is simple: when we see a useEffect call with no dep array
we insert the deps inferred for the lambda passed in. If the first
argument is not a lambda then we do not do anything.
This diff is the easy part. I think the harder part will be ensuring
that we can infer the deps even when we have to bail out of memoization.
We have no other features that *must* run regardless of rules of react
violations. Does anyone foresee any issues using the compiler passes to
infer reactive deps when there may be violations?
I have a few questions:
1. Will there ever be more than one instruction in a block containing a
useEffect? if no, I can get rid of the`addedInstrs` variable that I use
to make sure I insert the effect deps array temp creation at the right
spot.
2. Are there any cases for resolving the first argument beyond just
looking at the lvalue's identifier id that I'll need to take into
account? e.g., do I need to recursively resolve certain bindings?
---------
Co-authored-by: Mofei Zhang <feifei0@meta.com>
`enablePropagateScopeDepsHIR` is now used extensively in Meta. This has
been tested for over two weeks in our e2e tests and production.
The rest of this stack deletes `LoweredFunction.dependencies`, which the
non-hir version of `PropagateScopeDeps` depends on. To avoid a more
forked HIR (non-hir with dependencies and hir with no dependencies),
let's go ahead and clean up the non-hir version of
PropagateScopeDepsHIR.
Note that all fixture changes in this PR were previously reviewed when
they were copied to `propagate-scope-deps-hir-fork`. Will clean up /
merge these duplicate fixtures in a later PR
'
---
[//]: # (BEGIN SAPLING FOOTER)
Stack created with [Sapling](https://sapling-scm.com). Best reviewed
with [ReviewStack](https://reviewstack.dev/facebook/react/pull/31199).
* #31202
* #31203
* #31201
* #31200
* #31346
* __->__ #31199
Currently, the react compiler can not compile within callbacks which can
potentially cause over rendering. Consider this example:
```jsx
function Component(countries, onDelete) {
const name = useFoo();
return countries.map(() => {
return (
<Foo>
<Bar name={name}/>
<Baz onclick={onDelete} />
</Foo>
);
});
}
```
In this case, there's no memoization of the nested jsx elements. But
instead if we were to manually refactor the nested jsx into separate
component like this:
```jsx
function Component(countries, onDelete) {
const name = useFoo();
return countries.map(() => {
return <Temp name={name} onDelete={onDelete} />;
});
}
function Temp({ name, onDelete }) {
return (
<Foo>
<Bar name={name} />
<Baz onclick={onDelete} />
</Foo>
);
}
```
The compiler can now optimise both these components:
```jsx
function Component(countries, onDelete) {
const $ = _c(4);
const name = useFoo();
let t0;
if ($[0] !== name || $[1] !== onDelete || $[2] !== countries) {
t0 = countries.map(() => <Temp name={name} onDelete={onDelete} />);
$[0] = name;
$[1] = onDelete;
$[2] = countries;
$[3] = t0;
} else {
t0 = $[3];
}
return t0;
}
function Temp(t0) {
const $ = _c(7);
const { name, onDelete } = t0;
let t1;
if ($[0] !== name) {
t1 = <Bar name={name} />;
$[0] = name;
$[1] = t1;
} else {
t1 = $[1];
}
let t2;
if ($[2] !== onDelete) {
t2 = <Baz onclick={onDelete} />;
$[2] = onDelete;
$[3] = t2;
} else {
t2 = $[3];
}
let t3;
if ($[4] !== t1 || $[5] !== t2) {
t3 = (
<Foo>
{t1}
{t2}
</Foo>
);
$[4] = t1;
$[5] = t2;
$[6] = t3;
} else {
t3 = $[6];
}
return t3;
}
```
Now, when `countries` is updated by adding one single value, only the
newly added value is re-rendered and not the entire list. Rather than
having to do this manually, this PR teaches the react compiler to do
this transformation.
This PR adds a new pass (`OutlineJsx`) to capture nested jsx statements
and outline them in a separate component. This newly outlined component
can then by memoized by the compiler, giving us more fine grained
rendering.
Updates the compiler to always import from `react-compiler-runtime` by
default. The runtime then decides whether to use the official or
userspace implementation of useMemoCache.
Based on https://github.com/facebook/react/pull/30995 ([rendered
diff](https://github.com/jackpope/react/compare/inline-jsx-2...jackpope:react:inline-jsx-3?expand=1))
____
Some apps still use `react.element` symbols. Not only do we want to test
there but we also want to be able to upgrade those sites to
`react.transitional.element` without blocking on the compiler (we can
change the symbol feature flag and compiler config at the same time).
The compiler runtime uses `react.transitional.element`, so the snap
fixture will fail if we change the default here. However I confirmed
that commenting out the fixture entrypoint and running snap with
`react.element` will update the fixture symbols as expected.
This adds an `InlineJsxTransform` optimization pass, toggled by the
`enableInlineJsxTransform` flag. When enabled, JSX will be transformed
into React Element object literals, preventing runtime overhead during
element creation.
TODO:
- [ ] Add conditionals to make transform PROD-only
- [ ] Make the React element symbol configurable so this works with
runtimes that support `react.element` or `react.transitional.element`
- [ ] Look into additional optimization to pass props spread through
directly if none of the properties are mutated
Summary:
1. Minor refactor to provide a stable API for calling the compiler from the playground
2. Allows spaces in pass names without breaking the appearance of the playground by replacing spaces with in pass tabs
ghstack-source-id: 12a43ad86c
Pull Request resolved: https://github.com/facebook/react/pull/30988
Joseph Savona
mofeiZ
Joe Savona
lauren
Dimitri POSTOLOV
Jordan Brown
Aditya Subramanyam
Sathya Gunasekaran
Jack Pope
Mike Vitousek