We only really use this for the create APIs since the DOM requires it.
We could probably use the Host Context for this instead since they're
updated at the same time and the namespace is related to this concept.
Minor follow up to initial onRecoverableError PR.
When onRecoverableError is not provided to `createRoot`, the
renderer falls back to a default implementation. Originally I
implemented this with a host config method, but what we can do instead
is pass the default implementation the root constructor as if it were
a user provided one.
* [RFC] Add onHydrationError option to hydrateRoot
This is not the final API but I'm pushing it for discussion purposes.
When an error is thrown during hydration, we fallback to client
rendering, without triggering an error boundary. This is good because,
in many cases, the UI will recover and the user won't even notice that
something has gone wrong behind the scenes.
However, we shouldn't recover from these errors silently, because the
underlying cause might be pretty serious. Server-client mismatches are
not supposed to happen, even if UI doesn't break from the users
perspective. Ignoring them could lead to worse problems later. De-opting
from server to client rendering could also be a significant performance
regression, depending on the scope of the UI it affects.
So we need a way to log when hydration errors occur.
This adds a new option for `hydrateRoot` called `onHydrationError`. It's
symmetrical to the server renderer's `onError` option, and serves the
same purpose.
When no option is provided, the default behavior is to schedule a
browser task and rethrow the error. This will trigger the normal browser
behavior for errors, including dispatching an error event. If the app
already has error monitoring, this likely will just work as expected
without additional configuration.
However, we can also expose additional metadata about these errors, like
which Suspense boundaries were affected by the de-opt to client
rendering. (I have not exposed any metadata in this commit; API needs
more design work.)
There are other situations besides hydration where we recover from an
error without surfacing it to the user, or notifying an error boundary.
For example, if an error occurs during a concurrent render, it could be
due to a data race, so we try again synchronously in case that fixes it.
We should probably expose a way to log these types of errors, too. (Also
not implemented in this commit.)
* Log all recoverable errors
This expands the scope of onHydrationError to include all errors that
are not surfaced to the UI (an error boundary). In addition to errors
that occur during hydration, this also includes errors that recoverable
by de-opting to synchronous rendering. Typically (or really, by
definition) these errors are the result of a concurrent data race;
blocking the main thread fixes them by prevents subsequent races.
The logic for de-opting to synchronous rendering already existed. The
only thing that has changed is that we now log the errors instead of
silently proceeding.
The logging API has been renamed from onHydrationError
to onRecoverableError.
* Don't log recoverable errors until commit phase
If the render is interrupted and restarts, we don't want to log the
errors multiple times.
This change only affects errors that are recovered by de-opting to
synchronous rendering; we'll have to do something else for errors
during hydration, since they use a different recovery path.
* Only log hydration error if client render succeeds
Similar to previous step.
When an error occurs during hydration, we only want to log it if falling
back to client rendering _succeeds_. If client rendering fails,
the error will get reported to the nearest error boundary, so there's
no need for a duplicate log.
To implement this, I added a list of errors to the hydration context.
If the Suspense boundary successfully completes, they are added to
the main recoverable errors queue (the one I added in the
previous step.)
* Log error with queueMicrotask instead of Scheduler
If onRecoverableError is not provided, we default to rethrowing the
error in a separate task. Originally, I scheduled the task with
idle priority, but @sebmarkbage made the good point that if there are
multiple errors logs, we want to preserve the original order. So I've
switched it to a microtask. The priority can be lowered in userspace
by scheduling an additional task inside onRecoverableError.
* Only use host config method for default behavior
Redefines the contract of the host config's logRecoverableError method
to be a default implementation for onRecoverableError if a user-provided
one is not provided when the root is created.
* Log with reportError instead of rethrowing
In modern browsers, reportError will dispatch an error event, emulating
an uncaught JavaScript error. We can do this instead of rethrowing
recoverable errors in a microtask, which is nice because it avoids any
subtle ordering issues.
In older browsers and test environments, we'll fall back
to console.error.
* Naming nits
queueRecoverableHydrationErrors -> upgradeHydrationErrorsToRecoverable
* Hoist error codes import to module scope
When this code was written, the error codes map (`codes.json`) was
created on-the-fly, so we had to lazily require from inside the visitor.
Because `codes.json` is now checked into source, we can import it a
single time in module scope.
* Minify error constructors in production
We use a script to minify our error messages in production. Each message
is assigned an error code, defined in `scripts/error-codes/codes.json`.
Then our build script replaces the messages with a link to our
error decoder page, e.g. https://reactjs.org/docs/error-decoder.html/?invariant=92
This enables us to write helpful error messages without increasing the
bundle size.
Right now, the script only works for `invariant` calls. It does not work
if you throw an Error object. This is an old Facebookism that we don't
really need, other than the fact that our error minification script
relies on it.
So, I've updated the script to minify error constructors, too:
Input:
Error(`A ${adj} message that contains ${noun}`);
Output:
Error(formatProdErrorMessage(ERR_CODE, adj, noun));
It only works for constructors that are literally named Error, though we
could add support for other names, too.
As a next step, I will add a lint rule to enforce that errors written
this way must have a corresponding error code.
* Minify "no fallback UI specified" error in prod
This error message wasn't being minified because it doesn't use
invariant. The reason it didn't use invariant is because this particular
error is created without begin thrown — it doesn't need to be thrown
because it's located inside the error handling part of the runtime.
Now that the error minification script supports Error constructors, we
can minify it by assigning it a production error code in
`scripts/error-codes/codes.json`.
To support the use of Error constructors more generally, I will add a
lint rule that enforces each message has a corresponding error code.
* Lint rule to detect unminified errors
Adds a lint rule that detects when an Error constructor is used without
a corresponding production error code.
We already have this for `invariant`, but not for regular errors, i.e.
`throw new Error(msg)`. There's also nothing that enforces the use of
`invariant` besides convention.
There are some packages where we don't care to minify errors. These are
packages that run in environments where bundle size is not a concern,
like react-pg. I added an override in the ESLint config to ignore these.
* Temporarily add invariant codemod script
I'm adding this codemod to the repo temporarily, but I'll revert it
in the same PR. That way we don't have to check it in but it's still
accessible (via the PR) if we need it later.
* [Automated] Codemod invariant -> Error
This commit contains only automated changes:
npx jscodeshift -t scripts/codemod-invariant.js packages --ignore-pattern="node_modules/**/*"
yarn linc --fix
yarn prettier
I will do any manual touch ups in separate commits so they're easier
to review.
* Remove temporary codemod script
This reverts the codemod script and ESLint config I added temporarily
in order to perform the invariant codemod.
* Manual touch ups
A few manual changes I made after the codemod ran.
* Enable error code transform per package
Currently we're not consistent about which packages should have their
errors minified in production and which ones should.
This adds a field to the bundle configuration to control whether to
apply the transform. We should decide what the criteria is going
forward. I think it's probably a good idea to minify any package that
gets sent over the network. So yes to modules that run in the browser,
and no to modules that run on the server and during development only.
* Show soft errors when a text string or number is supplied as a child instead of throwing an error
* bring __DEV__ check first so that things inside get removed in prod.
* fix lint
The event priority constants exports by the reconciler package are
meant to be used by the reconciler (host config) itself. So it doesn't
make sense to export them from a module that requires them.
To break the cycle, we can move them to a separate module and import
that. This looks like a "deep import" of an internal module, which we
try to avoid, but conceptually these are part of the public interface
of the reconciler module. So, no different than importing from the main
`react-reconciler`.
We do need to be careful about not mixing these types of imports with
implementation details. Those are the ones to really avoid.
An unintended benefit of the reconciler fork infra is that it makes
deep imports harder. Any module that we treat as "public", like this
one, needs to account for the `enableNewReconciler` flag and forward
to the correct implementation.
* Add feature flag: enableStrongMemoryCleanup
Add a feature flag that will test doing a recursive clean of an unmount
node. This will disconnect the fiber graph making leaks less severe.
* Detach sibling pointers in old child list
When a fiber is deleted, it's still part of the previous (alternate)
parent fiber's list of children. Because children are a linked list, an
earlier sibling that's still alive will be connected to the deleted
fiber via its alternate:
live fiber
--alternate--> previous live fiber
--sibling--> deleted fiber
We can't disconnect `alternate` on nodes that haven't been deleted
yet, but we can disconnect the `sibling` and `child` pointers.
Will use this feature flag to test the memory impact.
* Combine into single enum flag
I combined `enableStrongMemoryCleanup` and `enableDetachOldChildList`
into a single enum flag. The flag has three possible values. Each level
is a superset of the previous one and performs more aggressive clean up.
We will use this to compare the memory impact of each level.
* Add Flow type to new host config method
* Re-use existing recursive clean up path
We already have a recursive loop that visits every deleted fiber. We
can re-use that one for clean up instead of adding another one.
Co-authored-by: Andrew Clark <git@andrewclark.io>
* Add `supportsMicrotasks` to the host config
Only certain renderers support scheduling a microtask, so we need a
renderer specific flag that we can toggle. That way it's off for some
renderers and on for others.
I copied the approach we use for the other optional parts of the host
config, like persistent mode and test selectors.
Why isn't the feature flag sufficient?
The feature flag modules, confusingly, are not renderer-specific, at
least when running the our tests against the source files. They are
meant to correspond to a release channel, not a renderer, but we got
confused at some point and haven't cleaned it up.
For example, when we run `yarn test`, Jest loads the flags from the
default `ReactFeatureFlags.js` module, even when we import the React
Native renderer — but in the actual builds, we load a different feature
flag module, `ReactFeatureFlags.native-oss.js.` There's no way in our
current Jest load a different host config for each renderer, because
they all just import the same module. We should solve this by creating
separate Jest project for each renderer, so that the flags loaded when
running against source are the same ones that we use in the
compiled bundles.
The feature flag (`enableDiscreteMicrotasks`) still exists — it's used
to set the React DOM host config's `supportsMicrotasks` flag to `true`.
(Same for React Noop) The important part is that turning on the feature
flag does *not* affect the other renderers, like React Native.
The host config will likely outlive the feature flag, too, since the
feature flag only exists so we can gradually roll it out and measure the
impact in production; once we do, we'll remove it. Whereas the host
config flag may continue to be used to disable the discrete microtask
behavior for RN, because RN will likely use a native (non-JavaScript)
API to schedule its tasks.
* Add `supportsMicrotask` to react-reconciler README
* Add the feature flag
* Add a host config method
* Wire it up to the work loop
* Export constants for third-party renderers
* Document for third-party renderers
There is a worry that `useOpaqueIdentifier` might run out of unique IDs if running for long enough. This PR moves the unique ID counter so it's generated per server renderer object instead. For people who render different subtrees, this PR adds a prefix option to `renderToString`, `renderToStaticMarkup`, `renderToNodeStream`, and `renderToStaticNodeStream` so identifiers can be differentiated for each individual subtree.
Adds several new experimental APIs to aid with automated testing.
Each of the methods below accepts an array of "selectors" that identifies a path (or paths) through a React tree. There are four basic selector types:
* Component: Matches Fibers with the specified React component type
* Role: Matches Host Instances matching the (explicit or implicit) accessibility role.
* Test name: Matches Host Instances with a data-testname attribute.
* Text: Matches Host Instances that directly contain the specified text.
* There is also a special lookahead selector type that enables further matching within a path (without actually including the path in the result). This selector type was inspired by the :has() CSS pseudo-class. It enables e.g. matching a <section> that contained a specific header text, then finding a like button within that <section>.
API
* findAllNodes(): Finds all Host Instances (e.g. HTMLElement) within a host subtree that match the specified selector criteria.
* getFindAllNodesFailureDescription(): Returns an error string describing the matched and unmatched portions of the selector query.
* findBoundingRects(): For all React components within a host subtree that match the specified selector criteria, return a set of bounding boxes that covers the bounds of the nearest (shallowed) Host Instances within those trees.
* observeVisibleRects(): For all React components within a host subtree that match the specified selector criteria, observe if it’s bounding rect is visible in the viewport and is not occluded.
* focusWithin(): For all React components within a host subtree that match the specified selector criteria, set focus within the first focusable Host Instance (as if you started before this component in the tree and moved focus forwards one step).
* Root API should clear non-empty roots before mounting
Legacy render-into-subtree API removes children from a container before rendering into it. The root API did not do this previously, but just left the children around in the document.
This commit adds a new FiberRoot flag to clear a container's contents before mounting. This is done during the commit phase, to avoid multiple, observable mutations.
* Add useOpaqueIdentifier Hook
We currently use unique IDs in a lot of places. Examples are:
* `<label for="ID">`
* `aria-labelledby`
This can cause some issues:
1. If we server side render and then hydrate, this could cause an
hydration ID mismatch
2. If we server side render one part of the page and client side
render another part of the page, the ID for one part could be
different than the ID for another part even though they are
supposed to be the same
3. If we conditionally render something with an ID , this might also
cause an ID mismatch because the ID will be different on other
parts of the page
This PR creates a new hook `useUniqueId` that generates a different
unique ID based on whether the hook was called on the server or client.
If the hook is called during hydration, it generates an opaque object
that will rerender the hook so that the IDs match.
Co-authored-by: Andrew Clark <git@andrewclark.io>
* Rename lower case isomorphic default exports modules to upper case named exports
We're somewhat inconsistent here between e.g. ReactLazy and memo.
Let's pick one.
This also moves the responder, fundamental, scope creators from shared
since they're isomorphic and same as the other creators.
* Move some files that are specific to the react-reconciler from shared
Individual renderers are allowed to deep require into the reconciler.
* Move files specific to react-dom from shared
react-interactions is right now dom specific (it wasn't before) so we can
type check it together with other dom stuff. Avoids the need for
a shared ReactDOMTypes to be checked by RN for example.
* Move ReactWorkTags to the reconciler
* Move createPortal to export from reconciler
Otherwise Noop can't access it since it's not allowed deep requires.
* Add options for forked entry points
We currently fork .fb.js entry points. This adds a few more options.
.modern.fb.js - experimental FB builds
.classic.fb.js - stable FB builds
.fb.js - if no other FB build, use this for FB builds
.experimental.js - experimental builds
.stable.js - stable builds
.js - used if no other override exists
This will be used to have different ES exports for different builds.
* Switch React to named exports
* Export named exports from the export point itself
We need to re-export the Flow exported types so we can use them in our code.
We don't want to use the Flow types from upstream since it doesn't have the non-public APIs that we have.
This should be able to use export * but I don't know why it doesn't work.
This actually enables Flow typing of React which was just "any" before.
This exposed some Flow errors that needs fixing.
* Create forks for the react entrypoint
None of our builds expose all exports and they all differ in at least one
way, so we need four forks.
* Set esModule flag to false
We don't want to emit the esModule compatibility flag on our CommonJS
output. For now we treat our named exports as if they're CommonJS.
This is a potentially breaking change for scheduler (but all those apis
are unstable), react-is and use-subscription. However, it seems unlikely
that anyone would rely on this since these only have named exports.
* Remove unused Feature Flags
* Let jest observe the stable fork for stable tests
This lets it do the negative test by ensuring that the right tests fail.
However, this in turn will make other tests that are not behind
__EXPERIMENTAL__ fail. So I need to do that next.
* Put all tests that depend on exports behind __EXPERIMENTAL__
Since there's no way to override the exports using feature flags
in .intern.js anymore we can't use these APIs in stable.
The tradeoff here is that we can either enable the negative tests on
"stable" that means experimental are expected to fail, or we can disable
tests on stable. This is unfortunate since some of these APIs now run on
a "stable" config at FB instead of the experimental.
* Switch ReactDOM to named exports
Same strategy as React.
I moved the ReactDOMFB runtime injection to classic.fb.js
Since we only fork the entrypoint, the `/testing` entrypoint needs to
be forked too to re-export the same things plus `act`. This is a bit
unfortunate. If it becomes a pattern we can consider forking in the
module resolution deeply.
fix flow
* Fix ReactDOM Flow Types
Now that ReactDOM is Flow type checked we need to fix up its types.
* Configure jest to use stable entry for ReactDOM in non-experimental
* Remove additional FeatureFlags that are no longer needed
These are only flagging the exports and no implementation details so we
can control them fully through the export overrides.
* Update Flow to 0.84
* Fix violations
* Use inexact object syntax in files from fbsource
* Fix warning extraction to use a modern parser
* Codemod inexact objects to new syntax
* Tighten types that can be exact
* Revert unintentional formatting changes from codemod
* allow nested `act()`s from different renderers
There are usecases where multiple renderers need to oprate inside an act() scope
- ReactDOM.render being used inside another component tree. The parent component will be rendered using ReactTestRenderer.create for a snapshot test or something.
- a ReactDOM instance interacting with a ReactTestRenderer instance (like for the new devtools)
This PR changes the way the acting sigils operate to allow for this. It keeps 2 booleans, one attached to React, one attached to the renderer. act() changes these values, and the workloop reads them to decide what warning to trigger.
I also renamed shouldWarnUnactedUpdates to warnsIfNotActing
* s/ReactIsActing/IsSomeRendererActing and s/ReactRendererIsActing/IsThisRendererActing
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