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
### Changes made:
- Running with enableFizzExternalRuntime (feature flag) and
unstable_externalRuntimeSrc (param) will generate html nodes with data
attributes that encode Fizz instructions.
```
<div
hidden data-rxi=""
data-bid="param0"
data-dgst="param1"
></div>
```
- Added an external runtime browser script
`ReactDOMServerExternalRuntime`, which processes and removes these nodes
- This runtime should be passed as to renderInto[...] via
`unstable_externalRuntimeSrc`
- Since this runtime is render blocking (for all streamed suspense
boundaries and segments), we want this to reach the client as early as
possible. By default, Fizz will send this script at the end of the shell
when it detects dynamic content (e.g. suspenseful pending tasks), but it
can be sent even earlier by calling `preinit(...)` inside a component.
- The current implementation relies on Float to dedupe sending
`unstable_externalRuntimeSrc`, so `enableFizzExternalRuntime` is only
valid when `enableFloat` is also set.
Add option for ref function to return a clean up function.
```jsx
<div ref={(_ref) => {
// Use `_ref`
return () => {
// Clean up _ref
};
}} />
```
If clean up function is not provided. Ref function is called with null
like it has been before.
```jsx
<div ref={(_ref) => {
if (_ref) {
// Use _ref
} else {
// Clean up _ref
}
}} />
```
In `<StrictMode>` in dev hooks are run twice on each render.
For `useId` the re-render pass uses the `updateId` implementation rather
than `mountId`. In the update path we don't increment the local id
counter. This causes the render to look like no id was used which
changes the tree context and leads to a different set of IDs being
generated for subsequent calls to `useId` in the subtree.
This was discovered here: https://github.com/vercel/next.js/issues/43033
It was causing a hydration error because the ID generation no longer
matched between server and client. When strict mode is off this does not
happen because the hooks are only run once during hydration and it
properly sees that the component did generate an ID.
The fix is to not reset the localIdCounter in `renderWithHooksAgain`. It
gets reset anyway once the `renderWithHooks` is complete and since we do
not re-mount the ID in the `...Again` pass we should retain the state
from the initial pass.
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## Summary
Submit https://github.com/facebook/react/pull/25698 again after fixing
the devtools regression tests in CI.
The PR changed lanes representation and some snapshot tests of devtools
captures lanes. In devtools tests for older versions, the updated lanes
representation no longer matched. The fix is to disable regression tests
for those tests.
## How did you test this change?
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```
./scripts/circleci/download_devtools_regression_build.js 18.0 --replaceBuild
node ./scripts/jest/jest-cli.js --build --project devtools --release-channel=experimental --reactVersion 18.0
```
Unrelated to this PR. There was some issue with jest caching when I
locally ran that command. it didn't seem to include the @reactVersion
transform, but if I manually modified `scripts/jest/preprocessor.js` or
ran ` yarn test --clearCache`, the jest test runs correctly.
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## Summary
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does the pull request solve?
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For more context: https://github.com/facebook/react/pull/25692
Based on https://github.com/facebook/react/pull/25695. This PR adds the
`SyncHydrationLane` so we rewind on sync updates during selective
hydration. Also added tests for ContinuouseHydration and
DefaultHydration lanes.
## How did you test this change?
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yarn test
Currently, if you call setState in render, you must render the exact
same hooks as during the first render pass.
I'm about to add a behavior where if something suspends, we can reuse
the hooks from the previous attempt. That means during initial render,
if something suspends, we should be able to reuse the hooks that were
already created and continue adding more after that. This will error
in the current implementation because of the expectation that every
render produces the same list of hooks.
In this commit, I've changed the logic to allow more hooks to be added
when replaying. But only during a mount — if there's already a current
fiber, then the logic is unchanged, because we shouldn't add any
additional hooks that aren't in the current fiber's list. Mounts are
special because there's no current fiber to compare to.
I haven't change any other behavior yet. The reason I've put this into
its own step is there are a couple tests that intentionally break the
Hook rule, to assert that React errors in these cases, and those happen
to be coupled to the behavior. This is undefined behavior that is always
accompanied by a warning and/or error. So the change should be safe.
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.
This just removes the error but the underlying issue is still there, and
it's likely that the best course of action is to not update in effects
and to wrap most updates in startTransition. However, that's more of a
performance concern which is not something we generally do even in
recoverable errors since they're less actionable and likely belong in
another channel. It is also likely that in many cases this happens so
rarely because you have to interact quickly enough that it can often be
ignored.
After changes to other parts of the model, this only happens for
sync/discrete updates. There are three scenarios that can happen:
- We replace a server rendered fallback with a client rendered fallback.
Other than this potentially causing some flickering in the loading
state, it's not a big deal.
- We replace the server rendered content with a client side fallback if
this suspends on the client. This is in line with what would happen
anyway. We will loose state of forms which is not intended semantics.
State and animations etc would've been lost anyway if it was client-side
so that's not a concern.
- We replace the server rendered content with a client side rendered
tree and lose selection/state and form state. While the content looks
the same, which is unfortunate.
In most scenarios it's a bad loading state but it's the same scenario as
flushing sync client-side. So it's not so bad.
The big change here is that we consider this a bug of React that we
should fix. Therefore it's not actionable to users today because it
should just get fixed. So we're removing the error early. Although
anyone that has fixed these issues already are probably better off for
it.
To fix this while still hydrating we need to be able to rewind a sync
tree and then replay it.
@tyao1 is going to add a Sync hydration lane. This is will allow us to
rewind the tree when we hit this state, and replay it given the previous
Context, hydrate and then reapply the update. The reason we didn't do
this originally is because it causes sync mode to unwind where as for
backwards compatibility we didn't want to cause that breaking semantic -
outside Suspense boundaries - and we don't want that semantic longer
term. We're only do this as a short term fix.
We should also have a way to leave a partial tree in place. If the sync
hydration lane suspends, we should be able to switch to a client side
fallback without throwing away the state of the DOM and then hydrate
later.
We now know how we want to fix this longer term. We're going to move all
Contexts into resumable trees like what Fizz/Flight does. That way we
can leave the original Context at the hydration boundaries and then
resume from there. That way the rewinding would never happen even in the
existence of a sync hydration lane which would only apply locally to the
dehydrated tree.
So the steps are 1) remove the error 2) add the sync hydration lane with
rewinding 3) Allow hiding server-rendered content while still not
hydrated 4) add resumable contexts at these boundaries.
Fixes#25625 and #24959.
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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?
## How did you test this change?
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`title` is a valid element descendent of `svg`. this PR adds a
prohibition on turning titles in svg into Resources.
This PR also adds additional warnings if you render something that is
almost a Resource inside an svg.
stacked on https://github.com/facebook/react/pull/25569
On the client noscript already never renders children so no resources
will be extracted from this context. On the server we now track if we
are in a noscript context and turn off Resource semantics in this scope
there are a few bugs where dom representations from SSR aren't
identified as Resources when they should be.
There are 3 semantics
Resource -> hoist to head, deduping, etc...
hydratable Component -> SSR'd and hydrated in place
non-hydratable Component -> never SSR'd, never hydrated, always inserted
on the client
this last category is small
(non stylesheet) links with onLoad and/or onError
async scripts with onLoad and/or onError
The reason we have this distinction for now is we need every SSR'd async
script to be assumable to be a Resource. we don't currently encode
onLoad on the server and so we couldn't otherwise tell if an async
script is a Resource or is an async script with an onLoad which would
not be a resource. To avoid this ambiguity we never emit the scripts in
SSR and assume they need to be inserted on the client.
We can explore changes to these semantics in the future or possibly
encode some identifier when we want to opt out of resource semantics but
still SSR the link or script.
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)
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
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.
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.
Adds a category of Resources of type `head` which will be used to track
the tags that go into the <head>
Currently only implements for `<title>`.
titles are keyed off their textContent so each time the title changes a
new resource will be created. Currently insertion is done by prepending
in the <head>. The argument here is that the newest title should "win"
if there are multiple rendered. This also helps when a navigation or
update causes a server rendered title to hang around but it is not the
most recent one.
* 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
* Add feature flag for external Fizz runtime
Only enabled for www for now
* Add option to load Fizz runtime from external file
When unstable_externalRuntimeSrc is provided, React will inject a script
tag that points to the provided URL.
Then, instead of emitting inline scripts, the Fizz stream will emit
HTML nodes with data attributes that encode the instructions. The
external runtime will detect these with a mutation observer and
translate them into runtime commands. This part isn't implemented in
this PR, though — all this does is set up the option to use
an external runtime, and inject the script tag.
The external runtime is injected at the same time as bootstrap scripts.
* 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
Fixes a bug that happens when you suspend in the shell (the part of the
tree that is not wrapped in a Suspense boundary) during a
discrete update.
There were two underyling issues. One was just a mistake:
RootDidNotComplete needs to be handled in both renderRootConcurrent and
renderRootSync, but it was only handled in renderRootConcurrent. I did
it this way because I thought this path was unreachable during a sync
update, but I neglected to consider that renderRootSync is sometimes
called for non-concurrent lanes, like when recovering from an error, or
patching up a mutation to an external store.
After I fixed that oversight, the other issue is that we intentionally
error if the shell suspends during a sync update. The idea was that you
should either wrap the tree in a Suspense boundary, or you should mark
the update as a transition to allow React to suspend.
However, this did not take into account selective hydration, which can
force a sync render before anything has even committed. There's no way
in that case to wrap the update in startTransition.
Our solution for now is to remove the error that happens when you
suspend in the shell during a sync update — even for discrete updates.
We will likely revisit this in the future. One appealing possibility is
to commit the whole root in an inert state, as if it were a hidden
Offscreen tree.
Co-authored-by: Sebastian Markbåge <sebastian@calyptus.eu>
Co-authored-by: Sebastian Markbåge <sebastian@calyptus.eu>
* 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>
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
- 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 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
* [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
Jan Kassens
mofeiZ
Samuel Susla
Josh Story
Tianyu Yao
Colin McDonnell
Andrew Clark
Sebastian Markbåge
Sebastian Silbermann
c0dedance
Jan Kassens
Vic Graf