We currently abuse the browser builds for Web streams derived
environments. We already have a special build for Bun but we should also
have one for [other "edge"
runtimes](https://runtime-keys.proposal.wintercg.org/) so that we can
maximally take advantage of the APIs that exist on each platform.
In practice, we currently check for a global property called
`AsyncLocalStorage` in the server browser builds which we shouldn't
really do since browsers likely won't ever have it. Additionally, this
should probably move to an import which we can't add to actual browser
builds where that will be an invalid import. So it has to be a separate
build. That's not done yet in this PR but Vercel will follow
Cloudflare's lead here.
The `deno` key still points to the browser build since there's no
AsyncLocalStorage there but it could use this same or a custom build if
support is added.
This is because Webpack has a `typeof ... === 'object'` before its esm
compat test.
This is unfortunate because it means we can't have a nice error in CJS
when someone does this:
```
const fn = require('client-fn');
fn();
```
I also fixed some checks in the validator that read off the client ref.
It shouldn't do those checks against a client ref, since those now
throw.
The old version of prettier we were using didn't support the Flow syntax
to access properties in a type using `SomeType['prop']`. This updates
`prettier` and `rollup-plugin-prettier` to the latest versions.
I added the prettier config `arrowParens: "avoid"` to reduce the diff
size as the default has changed in Prettier 2.0. The largest amount of
changes comes from function expressions now having a space. This doesn't
have an option to preserve the old behavior, so we have to update this.
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 enables the "exact_empty_objects" setting for Flow which makes
empty objects exact instead of building up the type as properties are
added in code below. This is in preparation to Flow 191 which makes this
the default and removes the config.
More about the change in the Flow blog
[here](https://medium.com/flow-type/improved-handling-of-the-empty-object-in-flow-ead91887e40c).
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
Flow introduced a new syntax to annotated the context type of a
function, this tries to update the rest and add 1 example usage.
- 2b1fb91a55 already added the changes
required for eslint.
- Jest transform is updated to use the recommended `hermes-parser` which
can parse current and Flow syntax and will be updated in the future.
- Rollup uses a new plugin to strip the flow types. This isn't ideal as
the npm module is deprecated in favor of using `hermes-parser`, but I
couldn't figure out how to integrate that with Rollup.
We originally had grand plans for using this Event concept for more but
now it's only meant to be used in combination with effects.
It's an Event in the FRP terms, that is triggered from an Effect.
Technically it can also be from another function that itself is
triggered from an existing side-effect but that's kind of an advanced
case.
The canonical case is an effect that triggers an event:
```js
const onHappened = useEffectEvent(() => ...);
useEffect(() => {
onHappened();
}, []);
```
We've heard from multiple contributors that the Reconciler forking
mechanism was confusing and/or annoying to deal with. Since it's
currently unused and there's no immediate plans to start using it again,
this removes the forking.
Fully removing the fork is split into 2 steps to preserve file history:
**#25774 previous PR that did the bulk of the work:**
- remove `enableNewReconciler` feature flag.
- remove `unstable_isNewReconciler` export
- remove eslint rules for cross fork imports
- remove `*.new.js` files and update imports
- merge non-suffixed files into `*.old` files where both exist
(sometimes types were defined there)
**This PR**
- rename `*.old` files
We've heard from multiple contributors that the Reconciler forking
mechanism was confusing and/or annoying to deal with. Since it's
currently unused and there's no immediate plans to start using it again,
this removes the forking.
Fully removing the fork is split into 2 steps to preserve file history:
**This PR**
- remove `enableNewReconciler` feature flag.
- remove `unstable_isNewReconciler` export
- remove eslint rules for cross fork imports
- remove `*.new.js` files and update imports
- merge non-suffixed files into `*.old` files where both exist
(sometimes types were defined there)
**#25775**
- rename `*.old` files
This improves the error message a bit and ensures that we recommend
putting the key first, not last, which ensures that the faster
`jsx-runtime` is used.
This only affects the modern "automatic" JSX transform.
In Strict Mode, during development, user functions are double invoked to
help detect side effects. Currently, the way we implement this is to
completely discard the first pass and start over. Theoretically this
should be fine because components are idempotent. However, it's a bit
tricky to get right because our implementation (i.e. `renderWithHooks`)
is not completely idempotent with respect to internal data structures,
like the work-in-progress fiber. In the past we've had to be really
careful to avoid subtle bugs — for example, during the initial mount,
`setState` functions are bound to the particular hook instances that
were created during that render. If we compute new hook instances, we
must also compute new children, and they must correspond to each other.
This commit addresses a similar issue that came up related to `use`:
when something suspends, `use` reuses the promise that was passed during
the first attempt. This is itself a form of memoization. We need to be
able to memoize the reactive inputs to the `use` call using a hook (i.e.
`useMemo`), which means, the reactive inputs to `use` must come from the
same component invocation as the output.
The solution I've chosen is, rather than double invoke the entire
`renderWithHook` function, we should double invoke each individual user
function. It's a bit confusing but here's how it works:
We will invoke the entire component function twice. However, during the
second invocation of the component, the hook state from the first
invocation will be reused. That means things like `useMemo` functions
won't run again, because the deps will match and the memoized result
will be reused.
We want memoized functions to run twice, too, so account for this, user
functions are double invoked during the *first* invocation of the
component function, and are *not* double invoked during the second
incovation:
- First execution of component function: user functions are double
invoked
- Second execution of component function (in Strict Mode, during
development): user functions are not double invoked.
It's hard to explain verbally but much clearer when you run the test
cases I've added.
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.
With the `react-dom/server-rendering-stub` you can import `react-dom` in
RSC so that you can call `preload` and `preinit` but if you don't alias
it, then requiring it breaks because we React.Component which doesn't
exist in the react subset.
`use` can avoid suspending on already resolved data by yielding to
microtasks. In a real, browser environment, we do this by scheduling a
platform task (i.e. postTask).
In a test environment, tasks are scheduled on a special internal queue
so that they can be flushed by the `act` testing API. So we need to add
support for this in `act`.
This behavior only works if you `await` the thenable returned by the
`act` call. We currently do not require that users do this. So I added a
warning, but it only fires if `use` was called. The old Suspense pattern
will not trigger a warning. This is to avoid breaking existing tests
that use Suspense.
The implementation of `act` has gotten extremely complicated because of
the subtle changes in behavior over the years, and our commitment to
maintaining backwards compatibility. We really should consider being
more restrictive in a future major release.
The changes are a bit confusing so I did my best to add inline comments
explaining how it works.
## Test plan
I ran this against Facebook's internal Jest test suite to confirm
nothing broke
* Add fetch instrumentation in cached contexts
* Avoid unhandled rejection errors for Promises that we intentionally ignore
In the final passes, we ignore the newly generated Promises and use
the previous ones. This ensures that if those generate errors, that we
intentionally ignore those.
* Add extra fetch properties if there were any
* 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
* Missing Hooks
* Remove www forks. These can use __SECRET... instead.
* Move cache to separate dispatcher
These will be available in more contexts than just render.
- 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 upgrade made more expressions invalidate refinements. In some
places this lead to a large number of suppressions that I automatically
suppressed and should be followed up on when the code is touched.
I think most of them might require either manual annotations or moving
a value into a const to allow refinement.
ghstack-source-id: a45b40abf0
Pull Request resolved: https://github.com/facebook/react/pull/25410
Ming Ye
Jan Kassens
Sebastian Markbåge
Sebastian Silbermann
Andrew Clark
Samuel Susla
zhangrenyang
Igor Berlenko
Jan Kassens