* Failing test: DevTools hook freezes timeline
The DevTools hook calls `requestCurrentTime` after the commit phase has
ended, which has the accidnental consequence of freezing the start
time for subsequent updates. If enough time goes by, the next update
will instantly expire.
I'll push a fix in the next commit.
* Read current time without marking event start time
`requestCurrentTime` is only meant to be used for updates, because
subsequent calls within the same event will receive the same time.
Messing this up has bad consequences.
I renamed it to `requestCurrentTimeForUpdate` and created a new
function that returns the current time without the batching heuristic,
called `getCurrentTime`.
Swapping `requestCurrentTime` for `getCurrentTime` in the DevTools
hook fixes the regression test added in the previous commit.
Special version of Jest's `it` for experimental tests. Tests marked as
experimental will run **both** stable and experimental modes. In
experimental mode, they work the same as the normal Jest methods. In
stable mode, they are **expected to fail**. This means we can detect
when a test previously marked as experimental can be un-marked when the
feature becomes stable. It also reduces the chances that we accidentally
add experimental APIs to the stable builds before we intend.
I added corresponding methods for the focus and skip APIs:
- `fit` -> `fit.experimental`
- `it.only` -> `it.only.experimental` or `it.experimental.only`
- `xit` -> `xit.experimental`
- `it.skip` -> `it.skip.experimental` or `it.experimental.skip`
Since `it` is an alias of `test`, `test.experimental` works, too.
`yarn build` defaults to building in experimental mode. To opt-out, set
the `RELEASE_CHANNEL` environment variable to `stable`. This is the same
as what we do when running tests via `yarn test`, to make local
development easier.
* SuspenseList support in DevTools
This adds SuspenseList tags to DevTools so that the name properly shows
up.
It also switches to use the tag instead of Symbol type for Suspense
components. We shouldn't rely on the type for any built-ins since that
field will disappear from the fibers. How the Fibers get created is an
implementation detail that can change e.g. with a compiler or if we
use instanceof checks that are faster than symbol comparisons.
* Add SuspenseList test to shell app
* Add a failing test for SuspenseList bug
* Store lastEffect before rendering
We can't reset the effect list to null because we don't rereconcile the
children so we drop deletion effects if we do that.
Instead we store the last effect as it was before we started rendering
so we can go back to where it was when we reset it.
We actually already do something like this when we delete the last row
for the tail="hidden" mode so we had a field available for it already.
Without the enableSuspenseServerRenderer flag there will never be a boundary match. Also when it is enabled, there might not be a boundary match if something was conditionally rendered by mistake.
With this PR it will now client render the content of a Suspense boundary in that case and issue a DEV only hydration warning. This is the only sound semantics for this case.
Unfortunately, landing this will once again break #16938. It will be less bad though because at least it'll just work by client rendering the content instead of hydrating and issue a DEV only warning.
However, we must land this before enabling the enableSuspenseServerRenderer flag since it does this anyway.
I did notice that we special case fallback={undefined} due to our unfortunate semantics for that. So technically a workaround that works is actually setting the fallback to undefined on the server and during hydration. Then flip it on only after hydration. That could be a workaround if you want to be able to have a Suspense boundary work only after hydration for some reason.
It's kind of unfortunate but at least those semantics are internally consistent. So I added a test for that.
This changes the "default" retryTime to NoWork which schedules at Normal
pri.
Dehydrated bouundaries normally hydrate at Never priority except when they
retry where we accidentally increased them to Normal because Never was used
as the default value. This changes it so NoWork is the default.
Dehydrated boundaries however get initialized to Never as the default.
Therefore they now hydrate as Never pri unless their priority gets
increased by a forced rerender or selective hydration.
This revealed that erroring at this Never priority can cause an infinite
rerender. So I fixed that too.
If a JSX element has both a children prop and children (ie. <div children={childOne}>{childTwo}</div>), IE throws an Multiple definitions of a property not allowed in strict mode. This modifies the previous fix (which used an Object.assign) by making the duplicate children a sequence expression on the next prop/child instead so that ordering is preserved. For example:
```
<Component children={useA()} foo={useB()} children={useC()}>{useD()}</Component>
```
should compile to
```
React.jsx(Component, {foo: (useA(), useB()), children: (useC(), useD)})
```
I'm doing this here instead of in the downstream repo so that if the
sync diff gets reverted, it doesn't revert this, too.
Once the sync has landed, and the callers are updated in www, I will
remove this.
* Tests run in experimental mode by default
For local development, you usually want experiments enabled. Unless
the release channel is set with an environment variable, tests will
run with __EXPERIMENTAL__ set to `true`.
* Remove concurrent APIs from stable builds
Those who want to try concurrent mode should use the experimental
builds instead.
I've left the `unstable_` prefixed APIs in the Facebook build so we
can continue experimenting with them internally without blessing them
for widespread use.
* Turn on SSR flags in experimental build
* Remove prefixed concurrent APIs from www build
Instead we'll use the experimental builds when syncing to www.
* Remove "canary" from internal React version string
* Download correct artifacts for release channel
Experimental builds should pull artifacts from the
`process_artifacts_experimental` job.
I think instead of two separate CI workflows, a better approach might
be to build stable artifacts to the `build` directory and the
experimental artifacts to a `build_experimental` directory, and
generate both within the same workflow. This would take some work since
lots of things assume the output directory is `build`, but something
to consider in the future.
* Prevent experimental promotion to stable
Adds a check to the `prepare-stable` script to prevent experimental
builds from being published using stable semver versions.
* Don't bother including `unstable_` in error
The method names don't get stripped out of the production bundles
because they are passed as arguments to the error decoder.
Let's just always use the unprefixed APIs in the messages.
* Set up experimental builds
The experimental builds are packaged exactly like builds in the stable
release channel: same file structure, entry points, and npm package
names. The goal is to match what will eventually be released in stable
as closely as possible, but with additional features turned on.
Versioning and Releasing
------------------------
The experimental builds will be published to the same registry and
package names as the stable ones. However, they will be versioned using
a separate scheme. Instead of semver versions, experimental releases
will receive arbitrary version strings based on their content hashes.
The motivation is to thwart attempts to use a version range to match
against future experimental releases. The only way to install or depend
on an experimental release is to refer to the specific version number.
Building
--------
I did not use the existing feature flag infra to configure the
experimental builds. The reason is because feature flags are designed
to configure a single package. They're not designed to generate multiple
forks of the same package; for each set of feature flags, you must
create a separate package configuration.
Instead, I've added a new build dimension called the **release
channel**. By default, builds use the **stable** channel. There's
also an **experimental** release channel. We have the option to add more
in the future.
There are now two dimensions per artifact: build type (production,
development, or profiling), and release channel (stable or
experimental). These are separate dimensions because they are
combinatorial: there are stable and experimental production builds,
stable and experimental developmenet builds, and so on.
You can add something to an experimental build by gating on
`__EXPERIMENTAL__`, similar to how we use `__DEV__`. Anything inside
these branches will be excluded from the stable builds.
This gives us a low effort way to add experimental behavior in any
package without setting up feature flags or configuring a new package.
* Transfer any pending promises from inner boundary to list
For non-hidden modes, this boundary should commit so this shouldn't be
needed but the nested boundary can make a second pass which forces these
to be recreated without resuspending. In this case, the outer list assumes
that it can collect the inner promises to still rerender if needed.
* Propagate suspense "context" change to nested SuspenseLists
This means that we always rerender any nested SuspenseLists together.
This bug looks similar to the previous one but is not based on the lack of
retry but that the retry only happens on the outer boundary but the inner
doesn't get a retry ping since it didn't know about its own promise after
the second pass.
* Remove "Invariant Violation" from dev errors
When I made the change to compile `invariant` to throw expressions, I
left a small runtime to set the error's `name` property to "Invariant
Violation" to maintain the existing behavior.
I think we can remove it. The argument for keeping it is to preserve
continuity in error logs, but this only affects development errors,
anyway: production error messages are replaced with error codes.
* Pass prod error messages directly to constructor
Updates the `invariant` transform to pass an error message string
directly to the Error constructor, instead of mutating the
message property.
Turns this code:
```js
invariant(condition, 'A %s message that contains %s', adj, noun);
```
into this:
```js
if (!condition) {
throw Error(
__DEV__
? `A ${adj} message that contains ${noun}`
: formatProdErrorMessage(ERR_CODE, adj, noun)
);
}
```
* Updated DevTools shell ignore warning message to account for recent changes in warning text
* Update DevTools console patching to patch the parent window's console rather than the iframe, to more accurately simulate real usage environment
* Remove dormant createBatch experiment
In a hybrid React app with multiple roots, `createBatch` is used to
coordinate an update to a root with its imperative container.
We've pivoted away from multi-root, hybrid React apps for now to focus
on single root apps.
This PR removes the API from the codebase. It's possible we'll add back
some version of this feature in the future.
* Remove unused export
The `performance.now` returns a timestamp in milliseconds as a float.
The browser has the option to adjust the precision of the float, but
it's usually more precise than a millisecond. However, this precision
is lost when the timestamp is logged by the Scheduler profiler, because
we store the numbers in an Int32Array.
This change multiplies the millisecond float value by 1000, giving us
three more degrees of precision.
Adds an API to explicitly prioritize hydrating the path to a particular DOM node without relying on events to do it.
The API uses the current scheduler priority to schedule it. For the same priority, the last one wins. This allows a similar effect as continuous events. This is useful for example to hydrate based on scroll position, or prioritize components that will upgrade to client-rendered-only content.
I considered having an API that explicitly overrides the current target(s). However that makes it difficult to coordinate across components in an app.
This just hydrates one target at a time but if it is blocked on I/O we could consider increasing priority of later targets too.
Dan Abramov