Adds a test that shows using <StrictMode /> anywhere outside of the root
node will not fire strict effects.
This works:
```js
root.render(
<StrictMode>
<App>
<Children />
</App>
</StrictMode>
);
```
This does not fire strict effects on mount:
```js
root.render(
<App>
<StrictMode>
<Children />
</StrictMode>
</App>
);
```
Before calling `emitTimingChunk` inside of `forwardDebugInfo`, we must
not increment `request.pendingChunks`, as this is already done inside of
the `emitTimingChunk` function.
I don't have a unit test for this, but manually verified that this fixes
the hanging responses in https://github.com/vercel/next.js/pull/73804.
In https://github.com/facebook/react/pull/30967 and
https://github.com/facebook/react/pull/30983 I added logging of the just
rendered components and the effects. However this didn't consider the
special Offscreen passes. So this adds the same thing to those passes.
Log component effect timings for disconnected/reconnected offscreen
subtrees. This includes initial mount of a Suspense boundary.
Log component render timings for reconnected and already offscreen
offscreen subtrees.
This treats workInProgressRoot work and rootWithPendingPassiveEffects
the same way. Basically as long as there's some work on the root, yield
the current task. Including passive effects. This means that passive
effects are now a continuation instead of a separate callback. This can
mean they're earlier or later than before. Later for Idle in case
there's other non-React work. Earlier for same Default if there's other
Default priority work.
This makes sense since increasing priority of the passive effects beyond
Idle doesn't really make sense for an Idle render.
However, for any given render at same priority it's more important to
complete this work than start something new.
Since we special case continuations to always yield to the browser, this
has the same effect as #31784 without implementing `requestPaint`. At
least assuming nothing else calls `requestPaint`.
<img width="587" alt="Screenshot 2024-12-14 at 5 37 37 PM"
src="https://github.com/user-attachments/assets/8641b172-8842-4191-8bf0-50cbe263a30c"
/>
As an alternative to #31784.
We should really just always yield each virtual task to a native task.
So that it's 1:1 with native tasks. This affects when microtasks within
each task happens. This brings us closer to native `postTask` semantics
which makes it more seamless to just use that when available.
This still doesn't yield when a task expires to protect against
starvation.
This flag controls the strict mode double invoke render/lifecycles/etc
behavior in Strict Mode.
The only place this flag is off is the test renderers, which it should
be on for.
If we can land this, we can follow up to remove the flag.
Add shape / type for global Object.keys. This is useful because
- it has an Effect.Read (not an Effect.Capture) as it cannot alias its
argument.
- Object.keys return an array
---
[//]: # (BEGIN SAPLING FOOTER)
Stack created with [Sapling](https://sapling-scm.com). Best reviewed
with [ReviewStack](https://reviewstack.dev/facebook/react/pull/31583).
* __->__ #31583
* #31582
We previously didn't track context variables in the hoistable values
sidemap of `propagateScopeDependencies`. This was overly conservative as
we *do* track the mutable range of context variables, and it is safe to
hoist accesses to context variables after their last direct / aliased
maybe-assignment.
```js
function Component({value}) {
// start of mutable range for `x`
let x = DEFAULT;
const setX = () => x = value;
const aliasedSet = maybeAlias(setX);
maybeCall(aliasedSet);
// end of mutable range for `x`
// here, we should be able to take x (and property reads
// off of x) as dependencies
return <Jsx value={x} />
}
```
---
[//]: # (BEGIN SAPLING FOOTER)
Stack created with [Sapling](https://sapling-scm.com). Best reviewed
with [ReviewStack](https://reviewstack.dev/facebook/react/pull/31582).
* #31583
* __->__ #31582
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
Stacked on #31737.
<img width="987" alt="Screenshot 2024-12-11 at 8 41 15 PM"
src="https://github.com/user-attachments/assets/438379a9-0138-4d02-a53a-419402839558"
/>
When mixing environments (like "use cache" or third party RSC) it's
useful to color and badge those components differently to differentiate.
I'm not putting them in separate tracks because when they do actually
execute, like cache misses or third party RSCs, they behave like they're
part of the same tree.
Stacked on #31736.
<img width="1223" alt="Screenshot 2024-12-11 at 8 21 12 PM"
src="https://github.com/user-attachments/assets/a7cbc04b-c831-476b-aa2f-baddec9461c9"
/>
This emits a placeholder when we're deduping a component. This starts
when the parent's self time ends, where we would've started rendering
this component if it wasn't already started. The end time is when the
actual render ends since the parent is also blocked by it.
Stacked on #31735.
This ensures that Server Components Track comes first. Since it's
typically rendered first on the server for initial load and then flows
into scheduler and client components work. Also puts it closer to the
Network and further away from "Main" JS.
<img width="769" alt="Screenshot 2024-12-11 at 5 31 41 PM"
src="https://github.com/user-attachments/assets/7198db0f-075e-4a78-8ea4-3bfbf06727cb"
/>
Same trick as in #31615.
We introduced the `unstable_useContextWithBailout` API to run compiler
based experiments. This API was designed to be an experiment proxy for
alternative approaches which would be heavier to implement. The
experiment turned out to be inconclusive. Since most of our performance
critical usage is already optimized, we weren't able to find a clear win
with this approach.
Since we don't have further plans for this API, let's clean it up.
Stacked on https://github.com/facebook/react/pull/31729
<img width="1436" alt="Screenshot 2024-12-11 at 3 36 41 PM"
src="https://github.com/user-attachments/assets/0a201913-0076-4bbf-be18-8f1df6c58313"
/>
The Server Components visualization is currently a tree flame graph
where parent spans the child. This makes it equivalent to the Client
Components visualization.
However, since Server Components can be async and therefore parallel, we
need to do something when two children are executed in parallel. This PR
bumps parallel children into a separate track and then within that track
if that child has more children it can grow within that track.
I currently just cut off more than 10 parallel tracks.
Synchronous Server Components are still in sequence but it's unlikely
because even a simple microtasky Async Component is still parallel.
<img width="959" alt="Screenshot 2024-12-11 at 4 31 17 PM"
src="https://github.com/user-attachments/assets/5ad6a7f8-7fa0-46dc-af51-78caf9849176"
/>
I think this is probably not a very useful visualization for Server
Components but we can try it out.
I'm also going to try a different visualization where parent-child
relationship is horizontal and parallel vertical instead, but it might
not be possible to make that line up in this tool. It makes it a little
harder to see how much different components (including their children)
impact the overall tree. If that's the only visualization it's also
confusing why it's different dimensions than the Client Component
version.
When implementing passive effects we did a pretty massive oversight.
While the passive effect is scheduled into its own scheduler task, the
scheduler doesn't always yield to the browser if it has time left. That
means that if you have a fast commit phase, it might try to squeeze in
the passive effects in the same frame but those then might end being
very heavy.
We had `requestPaint()` for this but that was only implemented for the
`isInputPending` experiment. It wasn't thought we needed it for the
regular scheduler because it yields "every frame" anyway - but it
doesn't yield every task. While the `isInputPending` experiment showed
that it wasn't actually any significant impact, and it was better to
keep shorter yield time anyway. Which is why we deleted the code.
Whatever small win it did see in some cases might have been actually due
to this issue rather than anything to do with `isInputPending` at all.
As you can see in https://github.com/facebook/react/pull/31782 we do
have this implemented in the mock scheduler and a lot of behavior that
we assert assumes that this works.
So this just implements yielding after `requestPaint` is called.
Before:
<img width="1023" alt="Screenshot 2024-12-14 at 3 40 24 PM"
src="https://github.com/user-attachments/assets/d60f4bb2-c8f8-4f91-a402-9ac25b278450"
/>
After:
<img width="1108" alt="Screenshot 2024-12-14 at 3 41 25 PM"
src="https://github.com/user-attachments/assets/170cdb90-a049-436f-9501-be3fb9bc04ca"
/>
Notice how in after the native task is split into two. It might not
always actually paint and the native scheduler might make the same
mistake and think it has enough time left but it's at least less likely
to.
We do have another way to do this. When we yield a continuation we also
yield to the native browser. This is to enable the Suspense Optimization
(currently disabled) to work. We could do the same for passive effects
and, in fact, I have a branch that does but because that requires a lot
more tests to be fixed it's a lot more invasive of a change. The nice
thing about this approach is that this is not even running in tests at
all and the tests we do have assert that this is the behavior already. 😬
This highlights the render phase as the tertiary color (green) when
we're render a hydration lane or offscreen lane.
I call the "Render" phase "Hydrated" instead in this case. For the
offscreen case we don't currently have a differentiation between
hydrated or activity. I just called that "Prepared". Even for the
hydration case where there's no discovered client rendered boundaries
it's more like it's preparing for an interaction rather than blocking
one. Where as for the other lanes the hydration might block something.
<img width="1173" alt="Screenshot 2024-12-12 at 11 23 14 PM"
src="https://github.com/user-attachments/assets/49ab1508-840f-4188-a085-18fe94b14187"
/>
In a follow up I'd like to color the components in the Components tree
green if they were hydrated but not the ones that was actually client
rendered e.g. due to a mismatch or forced client rendering so you can
tell the difference. Unfortunately, the current signals we have for this
get reset earlier in the commit phase than when we log these.
Another thing is that a failed hydration should probably be colored red
even though it ends up committing successfully. I.e. a recoverable
error.
Related to #31752.
When hydrating, we have two different ways of handling a Suspense
boundary that the server has already given up on and decided to client
render. If we have already hydrated the parent and then later this
happens, then we'll use the retry lane like any ping. If we discover
that it was already in client-render mode when we discover the Suspense
boundary for the first time, then schedule a default lane to let us
first finish the current render and then upgrade the priority to sync to
try to client render this boundary as soon as possible since we're
holding back content.
We used to use the `DefaultHydrationLane` for this but this is not
really a Hydration. It's actually a client render. If we get any other
updates flowing in from above at the same time we might as well do them
in the same pass instead of two passes. So this should be considered
more like any update.
This also means that visually the client render pass now gets painted as
a render instead of a hydration.
This show the flow of a shell being hydrated at the default priority,
then a Suspense boundary being discovered and hydrated at Idle and then
an inner boundary being discovered as client rendered which gets
upgraded to default.
<img width="1363" alt="Screenshot 2024-12-14 at 12 13 57 AM"
src="https://github.com/user-attachments/assets/a141133e-4856-4f38-a11f-f26bd00b6245"
/>
We're seeing errors when testing useResourceEffect in SSR and it turns
out we're missing the noop dispatcher function on Fizz.
I tested a local build with this change and it resolved the late
mutation errors in the e2e tests.
## Summary
This PR improves the Trace Updates feature by letting developers see
component names directly on the update overlay. Before this change, the
overlay only highlighted updated regions, leaving it unclear which
components were involved. With this update, you can now match visual
updates to their corresponding components, making it much easier to
debug rendering performance.
### New Feature: Show component names while highlighting
When the new **"Show component names while highlighting"** setting is
enabled, the update overlay display the names of affected components
above the rectangles, along with the update count. This gives immediate
context about what’s rendering and why. The preference is stored in
local storage and synced with the backend, so it’s remembered across
sessions.
### Improvements to Drawing Logic
The drawing logic has been updated to make the overlay sharper and
easier to read. Overlay now respect device pixel ratios, so they look
great on high-DPI screens. Outlines have also been made crisper, which
makes it easier to spot exactly where updates are happening.
> [!NOTE]
> **Grouping Logic and Limitations**
> Updates are grouped by their screen position `(left, top coordinates)`
to combine overlapping or nearby regions into a single group. Groups are
sorted by the highest update count within each group, making the most
frequently updated components stand out.
> Overlapping labels may still occur when multiple updates involve
components that overlap but are not in the exact same position. This is
intentional, as the logic aims to maintain a straightforward mapping
between update regions and component names without introducing
unnecessary complexity.
### Testing
This PR also adds tests for the new `groupAndSortNodes` utility, which
handles the logic for grouping and sorting updates. The tests ensure the
behavior is reliable across different scenarios.
## Before & After
https://github.com/user-attachments/assets/6ea0fe3e-9354-44fa-95f3-9a867554f74chttps://github.com/user-attachments/assets/32af4d98-92a5-47dd-a732-f05c2293e41b
---------
Co-authored-by: Ruslan Lesiutin <rdlesyutin@gmail.com>
When scheduling the initial root and when using
`unstable_scheduleHydration` we should use the Hydration Lanes rather
than the raw update lane. This ensures that we're always hydrating using
a Hydration Lane or the Offscreen Lane rather than other lanes getting
some random hydration in it.
This fixes an issue where updating a root while it is still hydrating
causes it to trigger client rendering when it could just hydrate and
then apply the update on top of that.
It also fixes a potential performance issue where
`unstable_scheduleHydration` gets batched with an update that then ends
up forcing an update of a boundary that requires it to rewind to do the
hydration lane anyway. Might as well just start with the hydration
without the update applied first.
I added a kill switch (`enableHydrationLaneScheduling`) just in case but
seems very safe given that using `unstable_scheduleHydration` at all is
very rare and updating the root before the shell hydrates is extremely
rare (and used to trigger a recoverable error).
Follow up to #31725.
I diffed against the Turbopack one to find any unexpected discrepancies.
Some parts are forked enough that it's hard to diff but I think I got
most of it.
We're still publishing RCs and creating canary version strings using the
RC naming convention. Setting the `canaryChannelLabel` back to canary
fixes the version names and tags after the 19 stable release.
Ricky
Hendrik Liebau
David Sancho
Sebastian Markbåge
Jack Pope
mofeiZ
Jordan Brown
Brooke
Joseph Savona
Piotr Tomczewski