<!--
Thanks for submitting a pull request!
We appreciate you spending the time to work on these changes. Please
provide enough information so that others can review your pull request.
The three fields below are mandatory.
Before submitting a pull request, please make sure the following is
done:
1. Fork [the repository](https://github.com/facebook/react) and create
your branch from `main`.
2. Run `yarn` in the repository root.
3. If you've fixed a bug or added code that should be tested, add tests!
4. Ensure the test suite passes (`yarn test`). Tip: `yarn test --watch
TestName` is helpful in development.
5. Run `yarn test --prod` to test in the production environment. It
supports the same options as `yarn test`.
6. If you need a debugger, run `yarn debug-test --watch TestName`, open
`chrome://inspect`, and press "Inspect".
7. Format your code with
[prettier](https://github.com/prettier/prettier) (`yarn prettier`).
8. Make sure your code lints (`yarn lint`). Tip: `yarn linc` to only
check changed files.
9. Run the [Flow](https://flowtype.org/) type checks (`yarn flow`).
10. If you haven't already, complete the CLA.
Learn more about contributing:
https://reactjs.org/docs/how-to-contribute.html
-->
## Summary
In https://github.com/facebook/react/pull/25504,
`react-server-dom-webpack/` was deprecated in favor of
`react-server-dom-webpack/client`, but a remaining import wasn't
adjusted accordingly.
As a result, the remaining conditions within the file are no longer
firing appropriately, which I ran into while playing around with a fork
of
[server-components-demo](https://github.com/reactjs/server-components-demo).
The `index.js` file now contains a
[placeholder](https://github.com/facebook/react/blob/main/packages/react-server-dom-webpack/index.js)
and the actual logic of the client now sits in `/client`.
## How did you test this change?
I replaced `require.resolve('../')` with `require.resolve('../client')`
in the `react-server-dom-webpack` package in `node_modules` and
confirmed that the output of the build looked good again.
There are two different switch statements that we use to unwrap a
`use`-ed promise, but there really only needs to be one. This was a
factoring artifact that arose because I implemented the yieldy `status`
instrumentation thing before I implemented `use` (for promises that are
thrown directly during render, which is the old Suspense pattern that
will be superseded by `use`).
This is a refactor to track the array of thenables that is preserved
across replays in the work loop instead of the Thenable module.
The reason is that I'm about to add additional state to the Thenable
module that is specific to a particular attempt — like the current
index — and is reset between replays. So it's helpful to keep the two
kinds of state separate so it's clearer which state gets reset when.
The array of thenables is not reset until the work-in-progress either
completes or unwinds.
This also makes the structure more similar to Fizz and Flight.
Same as #25537 but for Flight.
I was going to wait to do this later because the temporary
implementation of async components uses some of the same code that
non-used wakables do, but it's not so bad. I just had to inline one bit
of code, which we'll remove when we unify the implementation with `use`.
This diff adds styling to the compiler options editor. The floating input/output
toggle button on small screens now spans the bottom of the screen, so that it
doesn't block the compiler options.
Height overflows when adjusting screen size are complicated by Monaco Editor and
will be addressed in a later diff.
Test plan:
Start Playground and see the latest look of the compiler options editor beneath
the output section.
Removes all the `path: NodePath` values from various IR node types, replacing
them with `loc: SourceLocation`. This type is an alias for babel's source
location type plus a "generated" variant. The "OtherStatement" kind also used
the `path` to print back the original AST (since we don't look into these);
instead, we now capture the underlying `node` and emit that as-is during
codegen.
While I was doing this, i also fixed up the places where we had passed a null
path; the vast majority have a clear place we can pull a location from. For
example, `a ?? b` syntax creates some places/instructions for the `a != null`,
but those can all point back to the `a` location.
This commit introduces a small update to our fixture tests to allow certain jest
`test` modifiers to be added to fixture tests via a leading prefix in the
fixture name.
For example, `only.my-fixture.js` is the equivalent of writing
`test.only("my-fixture")`.
This currently basically lowers the code into the equivalent of
```
const vLeft = <left>;
const vNull = null;
const vCond = vLeft != vNull;
vCond ? vLeft : <right>
```
I created a temporary `Place` to hold the `null` constant value because the
binary operator in HIR accepts only `Place`s. Not sure if this is the preferred
approach. Alternatives I could think of:
- Allow constants as an alternative to Place?
- A `NotNull` operator for `<x> != null`
- Some other extension to the HIR?
## Proper Detection of Out-of-order Functions
The no-use-before-define rule from ESLint has a strange behavior in which it
treats variables differently than functions:
```javascript
function foo() {
return bar(X);
}
const X = null;
function bar(x) {}
```
By default, `bar(x)` has two errors: one because X is used before defined, and
once because `bar` is used before defined. The rule has an option `{variables:
false}` which only enables validation when the variable is from the same "scope"
as the reference, the net result of which is it means it doesn't report spurious
errors such as X being undefined. There is _also_ a `{functions: false}` option,
but for some reason that doesn't work the same way, it just turns off all
validation of references that came from functions. So enabling that option would
suppress the (spurious) error on invoking `bar()` above, but causes the rule to
miss invalid code such as:
```
function foo() {
return bar();
function bar() {}
}
```
This PR adds a fork of the rule that makes `{functions: false}` behave similarly
to `{variables: false}`, which should help avoid some of the spurious errors i
saw internally. The rule is exported from Forget itself, which will make it
easier to consume internally, in tests, and in the playground.
## Targeting the validation to Forget functions
Even with the above, there are still some false positives coming from code such
as:
```javascript
const x = foo();
function foo() {}
```
This PR changes codegen to ensure that the output of a function _always_ has the
body starting with 'use forget'. The ESLint rule then only looks at function
declarations/expressions whose body starts with that expression. The new unit
test confirms that the validation finds invalid reorderings even on functions
that weren't explicitly tagged as 'use forget'.
This just piggybacks on the infrastructure for handling Env.#variables.
In the future, a better approach would be to simplify the environment creation
and merging by leveraging the SSA property of the new IR -- 1) We don't need to
track IdentifierId per environment as they are all unique 2) Rather than
tracking values, we can just track Identifiers because Identifiers can never
be reassigned.
The semantics of lvalue changes based on whether lvalue.place.memberPath is null
or not. If it's null, then lvalue.place acts as the lvalue for the instruction,
otherwise it's just a reference to the memberPath specified location.
Ideally we'd have an MemberExpression IR that lowers this complex lvalue into a
temporary Place, uses this temporary place and stores back to the
MemberExpression.
Working around for now, will refactor to create a MemberExpression in the future
if necessary for other analysis.
Instead of using Place, use Identifier as the unit of comparison in SSA.
Place is too high level and can not be substituted for other Places (even those
with the same Identifier) as Place contain higher level metadata such as
memberPath.
Currently, HIR doesn't load global idenfifiers into a temporary Place which
means our SSA transform breaks when it tries to lookup this global identifier.
Instead of throwing, let's log and return the old place. This works for now but
will probably break when we start mutating globals, but at that point our HIR
builder will need fixes.
keys off `target` and `href`.
prepends on insertion similar to title.
only flushes on the server in the shell (should probably add a warning
if there are any to flush in a boundary)
This extends the scope of the cache and fetch instrumentation using
AsyncLocalStorage for microtasks. This is an intermediate step. It sets
up the dispatcher only once. This is unique to RSC because it uses the
react.shared-subset module for its shared state.
Ideally we should support multiple renderers. We should also have this
take over from an outer SSR's instrumented fetch. We should also be able
to have a fallback to global state per request where AsyncLocalStorage
doesn't exist and then the whole client-side solutions. I'm still
figuring out the right wiring for that so this is a temporary hack.
Revert fetch instrumentation so that it only affects RSC by applying it
only in the react-server condition of "react".
This helps make the rollout a little smoother because these affects
existing libraries that fetch during client components, and then gets
forever cached. We need to implement the GC first.
I haven't fully implemented the SSR part anyway.
The main problem that we discovered is that `"react"` and
`"react/react.shared-subset"` have separate dispatchers in an
environment that runs both Fizz and Flight. That's intentional and
sometimes a feature. However, in this case it means that we instrument
fetch twice and when you run Flight inside Fizz, that fetch goes into
both caches when it's supposed to only see the inner one. I'm not sure
how to solve that atm.
Adds some clarifying warnings when you render a component that is almost
a resource but isn't and the element was rendered outside the main
document tree (outside of `<body>` or `<head>`
replaces: https://github.com/facebook/react/pull/25535
This takes a more huerstic based approach with no new conditionals on
the hot path of fizz rendering.
If float is enabled
* title and script can only have simple children
* if non-simple children are found they will be ignored
* title and script are pushed in a single unit during pushStartInstance
including their children and closing tags
If float is not enabled
* the original pushing behaviors are in place and you can have complex
children but you will get warnings
To derisk the rollout of `use`, and simplify the implementation, this
reverts the yield-to-microtasks behavior for promises that are thrown
directly (as opposed to being unwrapped by `use`).
We may add this back later. However, the plan is to deprecate throwing a
promise directly and migrate all existing Suspense code to `use`, so the
extra code probably isn't worth it.
escapeTextForBrowser accepts any type so flow did not identify that we
were escaping a Chunk rather than a string. It's tricky because we
sometimes want to be able to escape non strings.
I've also updated the types for `Chunk` and `escapeTextForBrowser`
so that we should be able to catch this statically in the future.
The reason this did not show up in tests is almost all of our tests of
float (the areas affected by transpositions) are tested using the Node
runtime where a chunk type is a string. It may be wise to run these
tests in every runtime in the future or at least make sure there is
broad representation of resources in each specific runtime test suite.
stacked on https://github.com/facebook/react/pull/25514
This PR adds support for any type of Link as long as it has a string rel
and href and does not include an onLoad or onError property.
The semantics for generic link resources matches other head resources,
they will be inserted and removed as their ref counts go positive and
back to zero.
Keys are based on rel, href, sizes, and media.
on the server preconnect and prefetch-dns are privileged and will emit
near the start of the stream.
Josh Story
Leo Lamprecht
Sebastian Markbåge
Andrew Clark
Robert Zhang
Lauren Tan
Joseph Savona
Sathya Gunasekaran
Jan Kassens