I think this naming is a bit clearer. It means the root is currently
showing server rendered content that needs to be hydrated.
A dehydrated root is conceptually the same as what we call dehydrated
Suspense boundary, so this makes the naming of the root align with the
naming of subtrees.
The scheduling profiler markComponentRenderStopped method is supposed to be called when rendering finishes or when a value is thrown (Suspense or Error). Previously we were calling this in a Suspense-only path of `throwException`.
This PR updates the code to handle errors (or non-Thenables) thrown as well.
It also moves the mark logic the work loop `handleError` method, with Suspense/Error agnostic cleanup.
Indexed maps divide nested source maps into sections, annotated with a line and column offset. Since these sections are JSON and can be quickly parsed, we can easily separate them without doing the heavier base64 and VLQ decoding process. This PR updates our sourcemap parsing code to defer parsing of an indexed map section until we actually need to retrieve mappings from it.
* Remove pushEmpty
This is only used to support the assignID mechanism.
* Remove assignID mechanism
This effectively isn't used anyway because we always insert a dummy tag
into the fallback.
* Emit the template tag with an ID directly in pending boundaries
This ensures that assigning the ID is deterministic since it's done during
writing.
This also avoids emitting it for client rendered boundaries that start as
client rendered since we never need to refer to them.
* Move lazy ID initialization to the core implementation
We never need an ID before we write a pending boundary. This also ensures
that ID generation is deterministic by moving it to the write phase.
* Simplify the inserted scripts
We can assume that there are no text nodes before the template tag so this
simplifies the script that finds the comment node. It should be the direct
previous child.
I noticed a weird branch where we attach a ping listener even in legacy
mode. It's weird because this shouldn't be necessary. Fallbacks always
synchronously commit in legacy mode, so pings never happen. (A "ping" is
when a suspended promise resolves before the fallback has committed.)
It took me a moment to remember why this case exists, but it's related
to React.lazy.
There's a special case where we suspend while reconciling the children
of a Suspense boundary's inner Offscreen wrapper fiber. This happens
when a React.lazy component is a direct child of a Suspense boundary.
Suspense boundaries are implemented as multiple fibers, but they are a
single conceptual unit. The legacy mode behavior where we pretend the
suspended fiber committed as `null` won't work, because in this case the
"suspended" fiber is the inner Offscreen wrapper.
Because the contents of the boundary haven't started rendering yet (i.e.
nothing in the tree has partially rendered) we can switch to the
regular, concurrent mode behavior: mark the boundary with ShouldCapture
and enter the unwind phase.
However, even though we're switching to the concurrent mode behavior, we
don't need to attach a ping listener. So I refactored the logic so that
it doesn't escape back into the regular path.
It's not really a big deal that we attach an unncessary ping listener,
since this case is so unusual. The motivation is not performance related
— it's to make the logic clearer, because I'm about to add another case
where we trigger a Suspense boundary without attaching a ping listener.
This commit dramatically improves the performance of the hook names feature by replacing the source-map-js integration with custom mapping code built on top of sourcemap-codec. Based on my own benchmarking, this makes parsing 3-4 times faster. (The bulk of these changes are in SourceMapConsumer.js.)
While implementing this code, I also uncovered a problem with the way we were caching source-map metadata that was causing us to potential parse the same source-map multiple times. (I addressed this in a separate commit for easier reviewing. The bulk of these changes are in parseSourceAndMetadata.js.)
Altogether these changes dramatically improve the performance of the hooks parsing code.
One additional thing we could look into if the source-map download still remains a large bottleneck would be to stream it and decode the mappings array while it streams in rather than in one synchronous chunk after the full source-map has been downloaded.
Going to revert this until we figure out error reporting. It looks like
our downstream infra already supports some type of error recovery so
we might not need it here.
We're still in the process of migrating to the Fizz server renderer. In
the meantime, this makes the error semantics on the old server renderer
match the behavior of the new one: if an error is thrown, it triggers a
Suspense fallback, just as if it suspended (this part was already
implemented). Then the errored tree is retried on the client, where it
may recover and finish successfully.
Recoil uses useMutableSource behind a flag. I thought this was fine
because Recoil isn't used in any concurrent roots, so the behavior
would be the same, but it turns out that it is used by concurrent
roots in a few places.
I'm not expecting it to be hard to migrate to useSyncExternalStore, but
to de-risk the change I'm going to roll it out gradually with a flag. In
the meantime, I've added back the useMutableSource API.
There's a downstream workflow that runs the `print-warnings` command. We
can make it faster by scraping the warnings in CI and storing the
result as a build artifact.
The publish-preleases command prints the URL of the publish workflow
so that you can visit the page and follow along.
But it can take a few seconds before the workflow ID is available, after
you create the pipeline. So the script polls the workflow endpoint
until it's available.
The current polling limit is too low so I increased it.
I also updated the error message to provide more info.
Previously, DevTools always overrode the native console to dim or supress StrictMode double logging. It also overrode console.log (in addition to console.error and console.warn). However, this changes the location shown by the browser console, which causes a bad developer experience. There is currently a TC39 proposal that would allow us to extend console without breaking developer experience, but in the meantime this PR changes the StrictMode console override behavior so that we only patch the console during the StrictMode double render so that, during the first render, the location points to developer code rather than our DevTools console code.
This removes all the remaining references to the `build2` directory
except for the CI job that stores the artifacts. We'll keep the
`build2` artifact until downstream scripts are migrated to `build`.
Update all our local scripts to use `build` instead of `build2`.
There are still downstream scripts that depend on `build2`, though, so
we can't remove it yet.
Now that all the CI jobs have been migrated to the new build script,
we can start renaming the `build2` directory to `build`.
Since there are lots of scripts that reference `build2`, including
downstream scripts that live outside this repo, I'm going to keep
the `build2` directory around as a copy of `build`.
Then once all the references are updated, I will delete the copy.
* Move lint job to new, combined CI workflow
Moves the lint job our new, combined CI workflow.
After this, there is only one job remaining to be migrated. Then we
can delete the old workflow and build script.
* Remove "stable" CI workflow
This workflow is now empty so we can remove it
Moves the RELEASE_CHANNEL_stable_yarn_test_dom_fixtures job to our new,
combined CI workflow.
After this, there are only two jobs remaining to be migrated. Then we
can delete the old workflow and build script.
* Convert useSES shim tests to use React DOM
Idea is that eventually we'll run these tests against an actual build of
React DOM 17 to test backwards compatibility.
* Implement getServerSnapshot in userspace shim
If the DOM is not present, we assume that we are running in a server
environment and return the result of `getServerSnapshot`.
This heuristic doesn't work in React Native, so we'll need to provide
a separate native build (using the `.native` extension). I've left this
for a follow-up.
We can't call `getServerSnapshot` on the client, because in versions of
React before 18, there's no built-in mechanism to detect whether we're
hydrating. To avoid a server mismatch warning, users must account for
this themselves and return the correct value inside `getSnapshot`.
Note that none of this is relevant to the built-in API that is being
added in 18. This only affects the userspace shim that is provided
for backwards compatibility with versions 16 and 17.
Adds a third argument called `getServerSnapshot`.
On the server, React calls this one instead of the normal `getSnapshot`.
We also call it during hydration.
So it represents the snapshot that is used to generate the initial,
server-rendered HTML. The purpose is to avoid server-client mismatches.
What we render during hydration needs to match up exactly with what we
render on the server.
The pattern is for the server to send down a serialized copy of the
store that was used to generate the initial HTML. On the client, React
will call either `getSnapshot` or `getServerSnapshot` on the client as
appropriate, depending on whether it's currently hydrating.
The argument is optional for fully client rendered use cases. If the
user does attempt to omit `getServerSnapshot`, and the hook is called
on the server, React will abort that subtree on the server and
revert to client rendering, up to the nearest Suspense boundary.
For the userspace shim, we will need to use a heuristic (canUseDOM)
to determine whether we are in a server environment. I'll do that in
a follow up.
The replace-fork script depends on ESLint to fix the reconciler imports
— `.old` -> `.new` or vice versa. If ESLint crashes, it can leave the
imports in an incorrect state.
As a convenience, @bvaughn updated the script to automatically run
`git checkout -- .` if the ESLint command fails. An unintended
consequence of the strategy is that if the working directory is not
clean, then any uncommitted changes will be lost.
We need a better strategy for this that prevents the accidental loss of
work. One option is to exit early if the working directory is not clean
before you run the script, though that affects the usability of
the script.
An ideal solution would reset the working directory back to whatever
state it was in before the script ran, perhaps by stashing all the
changes and restoring them if the script aborts.
Until we think of something better, I've commmented out the branch.
This flag was broken due to a buggy race case in the ncp() command. The fix is amittedly a hack but improves on the existing behavior (of leaving the workspace in a broken state).
Andrew Clark
Brian Vaughn
Sebastian Markbåge
Damian Cyntler
Luna Ruan
salazarm
BowenandBowen Li
Sebastian Silbermann
38elements
Konstantin Popov
BIKI DAS
Juan
Ikko Ashimine
Abhay Gupta