Now that hook state is preserved while the work loop is suspended, we
don't need to track the thenable state in the work loop. We can track
it alongside the rest of the hook state.
This is a nice simplification and also aligns better with how it works
in Fizz and Flight.
The promises will still be cleared when the component finishes rendering
(either complete or unwind). In the future, we could stash the promises
on the fiber and reuse them during an update. However, this would only
work for `use` calls that occur before an prop/state/context is
processed, because `use` calls can only be assumed to execute in the
same order if no other props/state/context have changed. So it might not
be worth doing until we have finer grained memoization.
When an update flows into a dehydrated boundary, React cannot apply the
update until the boundary has finished hydrating. The way this currently
works is by scheduling a slightly higher priority task on the boundary,
using a special lane that's reserved only for this purpose. Because the
task is slightly higher priority, on the next turn of the work loop, the
Scheduler will force the work loop to yield (i.e. shouldYield starts
returning `true` because there's a higher priority task).
The downside of this approach is that it only works when time slicing is
enabled. It doesn't work for synchronous updates, because the
synchronous work loop does not consult the Scheduler on each iteration.
We plan to add support for selective hydration during synchronous
updates, too, so we need to model this some other way.
I've added a special internal exception that can be thrown to force the
work loop to interrupt the work-in-progress tree. Because it's thrown
from a React-only execution stack, throwing isn't strictly necessary —
we could instead modify some internal work loop state. But using an
exception means we don't need to check for this case on every iteration
of the work loop. So doing it this way moves the check out of the fast
path.
The ideal implementation wouldn't need to unwind the stack at all — we
should be able to hydrate the subtree and then apply the update all
within a single render phase. This is how we intend to implement it in
the future, but this requires a refactor to how we handle "stack"
variables, which are currently pushed to a per-render array. We need to
make this stack resumable, like how context works in Flight and Fizz.
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Following
[comment](https://github.com/facebook/react/pull/25437#discussion_r1010944983)
in #25437 , the external runtime implementation should be moved from
`react-dom` to `react-dom-bindings`.
I did have a question here:
I set the entrypoint to `react-dom/unstable_server-external-runtime.js`,
since a.) I was following #25436 as an example and b.)
`react-dom-bindings` was missing a `README.md` and `npm/`. This also
involved adding the external runtime to `package.json`.
However, the external runtime isn't really a `react-dom` entrypoint. Is
this change alright, or should I change the bundling code instead?
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The old (unstable) mechanism for suspending was to throw a promise. The
purpose of throwing is to interrupt the component's execution, and also
to signal to React that the interruption was caused by Suspense as
opposed to some other error.
A flaw is that throwing is meant to be an implementation detail — if
code in userspace catches the promise, it can lead to unexpected
behavior.
With `use`, userspace code does not throw promises directly, but `use`
itself still needs to throw something to interrupt the component and
unwind the stack.
The solution is to throw an internal error. In development, we can
detect whether the error was caught by a userspace try/catch block and
log a warning — though it's not foolproof, since a clever user could
catch the object and rethrow it later.
The error message includes advice to move `use` outside of the try/catch
block.
I did not yet implement the warning in Flight.
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.
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.
Stacked on #25508
This PR adds meta tags as a resource type.
metas are classified in the following priority
1. charset
2. http-equiv
3. property
4. name
5. itemprop
when using property, there is special logic for og type properties where
a `property="og:image:height"` following a `property="og:image"` will
inherit the key of the previous tag. this relies on timing effects to
stay consistent so when mounting new metas it is important that if
structured properties are being used all members of a structure mount
together. This is similarly true for arrays where the implicit
sequential order defines the array structure. if you need an array you
need to mount all array members in the same pass.
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.
* 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
* float enhance!!!
Support preinit as script
Support resources from async scripts
Support saving the precedence place when rendering the shell
There was a significant change to the flushing order of resources which follows the general principal of...
1. stuff that blocks display
2. stuff that we know will be used
3. stuff that was explicitly preloaded
As a consequence if you preinit a style now it won't automatically flush in the shell unless you actually depend on it in your tree. To avoid races with precedence order we now emit a tag that saves the place amongst the precedence hierarchy so late insertions still end up where they were intended
There is also a novel hydration pathway for certain tags. If you render an async script with an onLoad or onError it will always treat it like an insertion rather than a hydration.
* restore preinit style flushing behavior and nits
* Print built-in specific error message for toJSON
This is a better message for Date.
Also, format the message to highlight the affected prop.
* Describe error messages using JSX elements in DEV
We don't have access to the grand parent objects on the stack so we stash
them on weakmaps so we can access them while printing error messages.
Might be a bit slow.
* Capitalize Server/Client Component
* Special case errror messages for children of host components
These are likely meant to be text content if they're not a supported object.
* Update error messages
The download-build script works by scraping the CircleCI job number from
the GitHub status API. Yes, I know this is super hacky but last I
checked this was the least bad of not a lot of options. Because the
response is paginated, sometimes the status for the build job exceeds
the page size.
This increases the page size to 100 so this is less likely to happen.
It'd be great to find a better way to download the artifacts. I don't
love how brittle this solution is. I think switching to the GitHub
Checks API might be worth trying, but last I looked into it, it has
other flaws.
* Scaffolding for react-dom/unstable_external-server-runtime
Implements a new bundle type for in our build config called
BROWSER_SCRIPT. This is intended for scripts that get delivered straight
to the browser without needing to be processed by a bundler. (And also
doesn't include any extra UMD crap.)
Right now there's only a single use case so I didn't stress about making
it general purpose.
The use case is: a script that loads the Fizz browser runtime, and sets
up a MutationObserver to receive instructions as HTML streams in. This
will be an alternative option to the default Fizz behavior of sending
the runtime down as inline script tags, to accommodate environments
where inline script tags are not allowed.
There's no development version of this bundle because it doesn't contain
any warnings or run any user code.
None of the actual implementation is in this PR; it just sets up the
build infra.
Co-authored-by: Mofei Zhang <feifei0@fb.com>
* Set BUNDLE_SCRIPT's GCC output format to ES5
This removes the automatic 'use strict' directive, which we don't need.
Co-authored-by: Mofei Zhang <feifei0@fb.com>
* Move Fizz inline instructions to unified module
Instead of a separate module per instruction, this exports all of them
from a unified module.
In the next step, I'll add a script to generate this new module.
* Add script to generate inline Fizz runtime
This adds a script to generate the inline Fizz runtime. Previously, the
runtime source was in an inline comment, and a compiled version of the
instructions were hardcoded as strings into the Fizz implementation,
where they are injected into the HTML stream.
I've moved the source for the instructions to a regular JavaScript
module. A script compiles the instructions with Closure, then generates
another module that exports the compiled instructions as strings.
Then the Fizz runtime imports the instructions from the
generated module.
To build the instructions, run:
yarn generate-inline-fizz-runtime
In the next step, I'll add a CI check to verify that the generated files
are up to date.
* Check in CI if generated Fizz runtime is in sync
The generated Fizz runtime is checked into source. In CI, we'll ensure
it stays in sync by running the script and confirming nothing changed.
* 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.
Publish an aliasable entry for `react-dom` top level package exports for use in server environments. This is a stub containing only the exports that we expect to retain in the top level once 19 is released
* track resources in different roots separately
* flow types
* add test demonstrating portals deep into shadowRoots
* revert hostcontext changes
* lints
* funge style cache key a la ReactDOMComponentTree
* hide hacks in componentTree
* Update safe-string-coercion to handle additions of string literals
Adding strings shouldn't trigger a lint violation of this rule, since
adding strings are always safe.
- 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
This was a large upgrade that removed "classic mode" and made "types first" the only option.
Most of the needed changes have been done in previous PRs, this just fixes up the last few instances.
ghstack-source-id: 9612d95ba4
Pull Request resolved: https://github.com/facebook/react/pull/25408
This contains one code change, renaming the local function `ChildReconciler` to `createChildReconciler` as it's called as a function, not a constructor and to free up the name for the return value.
* [Fizz/Float] Float for stylesheet resources
This commit implements Float in Fizz and on the Client. The initial set of supported APIs is roughly
1. Convert certain stylesheets into style Resources when opting in with precedence prop
2. Emit preloads for stylesheets and explicit preload tags
3. Dedupe all Resources by href
4. Implement ReactDOM.preload() to allow for imperative preloading
5. Implement ReactDOM.preinit() to allow for imperative preinitialization
Currently supports
1. style Resources (link rel "stylesheet")
2. font Resources (preload as "font")
later updates will include support for scripts and modules
This was added back in #17880 to make CI pass for an unrelated change.
This limits the max worker setting to CI environments as removing the setting completely still seems to break on CircleCI.
This lets us share it with react-server-dom-webpack while still having a
dependency on react-dom. It also makes somewhat sense from a bundling
perspective since react-dom is an external to itself.
