* Fix type of Offscreen props argument
Fixes an oversight from a previous refactor. The fiber that wraps
a Suspense component's children used to be a Fragment but now it's on
Offscreen fiber, so its props type has changed. There's a special
hydration path where I forgot to update this. This isn't observable
because we don't ever end up rendering this particular fiber (because
the Suspense boundary is in its fallback state) but we should fix it
anyway to avoid a potential regression in the future.
* Extract createOffscreenFromFiber logic
...into a new method called `createWorkInProgressOffscreenFiber`. Just
for symmetry with `updateWorkInProgressOffscreenFiber`. Doesn't change
any behavior.
* [Fabric] Use container node to hide/show tree
This changes how we hide and show the contents of Offscreen boundaries
in the React Fabric renderer (persistent mode), and also Suspense
boundaries which use the same feature.=
The way it used to work was that when a boundary is hidden, in the
complete phase, instead of calling the normal `cloneInstance` method
inside `appendAllChildren`, we would call a forked method called
`cloneHiddenInstance` for each of the nearest host nodes within the
subtree. This design was largely based on how it works in React DOM
(mutation mode), where instead of cloning the nearest host nodes, we
mutate their `style.display` property.
The motivation for doing it this way in React DOM was because there's no
built-in browser API for hiding a collection of DOM nodes without
affecting their layout.
In Fabric, however, there is no such limitation, so we can instead wrap
in an extra host node and apply a hidden style.
The immediate motivation for this change is that Fabric on Android has a
view pooling mechanism for instances that relies on the assumption that
a current Fiber that is cloned and replaced by a new Fiber will never
appear in a future commit. When this assumption is broken, it may cause
crashes. In the current implementation, that can indeed happen when a
node that was previously hidden is toggled back to visible. Although
this change sidesteps the issue, we may introduce in other features in
the future that would benefit from being able to revert back to an older
node without cloning it again, such as animations.
The way I've implemented this is to insert an additional HostComponent
fiber as the child of each OffscreenComponent. The extra fiber is not
ideal — the way I'd prefer to do it is to attach the host instance to
the OffscreenComponent. However, the native Fabric implementation
currently expects a 1:1 correspondence between HostComponents and host
instances, so I've deferred that optimization to a future PR to derisk
fixing the Fabric pooling crash. I left a TODO in the host config with a
description of the remaining steps, but this alone should be sufficient
to unblock.
We added this unstable feature a few years ago, as a way to opt out of
context updates, but it didn't prove useful in practice.
We have other proposals for how to address the same problem, like
context selectors.
Since it was prefixed with `unstable_`, we should be able to remove it
without consequence. The hook API already warned if you used it.
Even if someone is using it somewhere, it's meant to be an optimization
only, so if they are using the API properly, it should not have any
semantic impact.
Changed previous error message from:
> Cannot read from mutable source during the current render without tearing. This is a bug in React. Please file an issue.
To:
> Cannot read from mutable source during the current render without tearing. This may be a bug in React. Please file an issue.
Also added a DEV only warning about the unsafe side effect:
> A mutable source was mutated while the %s component was rendering. This is not supported. Move any mutations into event handlers or effects.
I think this is the best we can do without adding production overhead that we'd probably prefer to avoid.
* Formalize the Wakeable and Thenable types
We use two subsets of Promises throughout React APIs. This introduces
the smallest subset - Wakeable. It's the thing that you can throw to
suspend. It's something that can ping.
I also use a shared type for Thenable in the cases where we expect a value
so we can be a bit more rigid with our us of them.
* Make Chunks into Wakeables instead of using native Promises
This value is just going from here to React so we can keep it a lighter
abstraction throughout.
* Renamed thenable to wakeable in variable names
useMutableSource hook
useMutableSource() enables React components to safely and efficiently read from a mutable external source in Concurrent Mode. The API will detect mutations that occur during a render to avoid tearing and it will automatically schedule updates when the source is mutated.
RFC: reactjs/rfcs#147
* Added missing @flow pragma to React.js
* Fixed useContext() return type definition
* Fixed previously masked Flow errors in DevTools and react-interactions packages
* Added displayName to internal Context Flow type
* Removed Flow generic annotations for createResponder
This seems to cause a parsing error. (Not sure why.) The API is deprecated anyway so I'm being lazy for now and just adding a .
* 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
* Same as previous commit, but for Flare
I don't know what the public API for setting the event priority should
be. Right now it accepts a numeric enum, but is this what we want?
Maybe it should be a string enum? I've punted on this for now.
* Add test for hover events
