Moves writing queues to renderState.
We shouldn't need the resource tracking's value. We just need to know if
that resource has already been emitted. We can use a Set for this. To
ensure that set is directly serializable we can just use a
dictionary-like object with no value.
See individual commits for special cases.
Just moving some internal code around again.
I originally encoded what type of work using startRender vs
startPrerender. I had intended to do more forking of the work loop but
we've decided not to go with that strategy. It also turns out that
forking when we start working is actually too late because of a subtle
thing where you can call abort before work begins. Therefore it's
important that starting the work comes later.
This is basically the implementation for the prerender pass.
Instead of forking basically the whole implementation for prerender, I
just add a conditional field on the request. If it's `null` it behaves
like before. If it's non-`null` then instead of triggering client
rendered boundaries it triggers those into a "postponed" state which is
basically just a variant of "pending". It's supposed to be filled in
later.
It also builds up a serializable tree of which path can be followed to
find the holes. This is basically a reverse `KeyPath` tree.
It is unfortunate that this approach adds more code to the regular Fizz
builds but in practice. It seems like this side is not going to add much
code and we might instead just want to merge the builds so that it's
smaller when you have `prerender` and `resume` in the same bundle -
which I think will be common in practice.
This just implements the prerender side, and not the resume side, which
is why the tests have a TODO. That's in a follow up PR.
This exposes a `resume()` API to go with the `prerender()` (only in
experimental). It doesn't work yet since we don't yet emit the postponed
state so not yet tested.
The main thing this does is rename ResponseState->RenderState and
Resources->ResumableState. We separated out resources into a separate
concept preemptively since it seemed like separate enough but probably
doesn't warrant being a separate concept. The result is that we have a
per RenderState in the Config which is really just temporary state and
things that must be flushed completely in the prerender. Most things
should be ResumableState.
Most options are specified in the `prerender()` and transferred into the
`resume()` but certain options that are unique per request can't be.
Notably `nonce` is special. This means that bootstrap scripts and
external runtime can't use `nonce` in this mode. They need to have a CSP
configured to deal with external scripts, but not inline.
We need to be able to restore state of things that we've already emitted
in the prerender. We could have separate snapshot/restore methods that
does this work when it happens but that means we have to explicitly do
that work. This design is trying to keep to the principle that we just
work with resumable data structures instead so that we're designing for
it with every feature. It also makes restoring faster since it's just
straight into the data structure.
This is not yet a serializable format. That can be done in a follow up.
We also need to vet that each step makes sense. Notably stylesToHoist is
a bit unclear how it'll work.
This adds an experimental `unstable_postpone(reason)` API.
Currently we don't have a way to model effectively an Infinite Promise.
I.e. something that suspends but never resolves. The reason this is
useful is because you might have something else that unblocks it later.
E.g. by updating in place later, or by client rendering.
On the client this works to model as an Infinite Promise (in fact,
that's what this implementation does). However, in Fizz and Flight that
doesn't work because the stream needs to end at some point. We don't
have any way of knowing that we're suspended on infinite promises. It's
not enough to tag the promises because you could await those and thus
creating new promises. The only way we really have to signal this
through a series of indirections like async functions, is by throwing.
It's not 100% safe because these values can be caught but it's the best
we can do.
Effectively `postpone(reason)` behaves like a built-in [Catch
Boundary](https://github.com/facebook/react/pull/26854). It's like
`raise(Postpone, reason)` except it's built-in so it needs to be able to
be encoded and caught by Suspense boundaries.
In Flight and Fizz these behave pretty much the same as errors. Flight
just forwards it to retrigger on the client. In Fizz they just trigger
client rendering which itself might just postpone again or fill in the
value. The difference is how they get logged.
In Flight and Fizz they log to `onPostpone(reason)` instead of
`onError(error)`. This log is meant to help find deopts on the server
like finding places where you fall back to client rendering. The reason
that you pass in is for that purpose to help the reason for any deopts.
I do track the stack trace in DEV but I don't currently expose it to
`onPostpone`. This seems like a limitation. It might be better to expose
the Postpone object which is an Error object but that's more of an
implementation detail. I could also pass it as a second argument.
On the client after hydration they don't get passed to
`onRecoverableError`. There's no global `onPostpone` API to capture
postponed things on the client just like there's no `onError`. At that
point it's just assumed to be intentional. It doesn't have any `digest`
or reason passed to the client since it's not logged.
There are some hacky solutions that currently just tries to reuse as
much of the existing code as possible but should be more properly
implemented.
- Fiber is currently just converting it to a fake Promise object so that
it behaves like an infinite Promise.
- Fizz is encoding the magic digest string `"POSTPONE"` in the HTML so
we know to ignore it but it should probably just be something neater
that doesn't share namespace with digests.
Next I plan on using this in the `/static` entry points for additional
features.
Why "postpone"? It's basically a synonym to "defer" but we plan on using
"defer" for other purposes and it's overloaded anyway.
This PR adds a preload for bootstrapScripts. preloads are captured
synchronously when you create a new Request and as such the normal logic
to check if a preload already exists is skipped.
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
### 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.
* 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
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.
Before this change we weren't calling onError nor onFatalError if you abort
before completing the shell.
This means that the render never completes and hangs.
Aborting early can happen before even creating the stream for AbortSignal,
before rendering starts in Node since there's an setImmediate atm, or
during rendering.
* [Fizz] Support abort reasons
Fizz supports aborting the render but does not currently accept a reason. The various render functions that use Fizz have some automatic and some user-controlled abort semantics that can be useful to communicate with the running program and users about why an Abort happened.
This change implements abort reasons for renderToReadableStream and renderToPipeable stream as well as legacy renderers such as renderToString and related implementations.
For AbortController implementations the reason passed to the abort method is forwarded to Fizz and sent to the onError handler. If no reason is provided the AbortController should construct an AbortError DOMException and as a fallback Fizz will generate a similar error in the absence of a reason
For pipeable streams, an abort function is returned alongside pipe which already accepted a reason. That reason is now forwarded to Fizz and the implementation described above.
For legacy renderers there is no exposed abort functionality but it is used internally and the reasons provided give useful context to, for instance to the fact that Suspense is not supported in renderToString-like renderers
Sebastian Markbåge
Josh Story
Jan Kassens
mofeiZ
Andrew Clark
Jan Kassens