* 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
Some of our internal reconciler types have leaked into other packages.
Usually, these types are treated as opaque; we don't read and write
to its fields. This is good.
However, the type is often passed back to a reconciler method. For
example, React DOM creates a FiberRoot with `createContainer`, then
passes that root to `updateContainer`. It doesn't do anything with the
root except pass it through, but because `updateContainer` expects a
full FiberRoot, React DOM is still coupled to all its fields.
I don't know if there's an idiomatic way to handle this in Flow. Opaque
types are simlar, but those only work within a single file. AFAIK,
there's no way to use a package as the boundary for opaqueness.
The immediate problem this presents is that the reconciler refactor will
involve changes to our internal data structures. I don't want to have to
fork every single package that happens to pass through a Fiber or
FiberRoot, or access any one of its fields. So my current plan is to
share the same Flow type across both forks. The shared type will be a
superset of each implementation's type, e.g. Fiber will have both an
`expirationTime` field and a `lanes` field. The implementations will
diverge, but not the types.
To do this, I lifted the type definitions into a separate module.
* Remove unnecessary CapturedError fields.
componentName is not necessary and is misleading when the error is caused
elsewhere in the stack. The stack is sufficient.
The many error boundary fields are unnecessary because they can be inferred
by the boundary itself.
* Don't attempt to build a stack twice
If it was possible, it would've been done in createCapturedValue.
* Push the work needed by the works into the forks
This avoids needing this in the npm published case.
* Add stack unwinding phase for handling errors
A rewrite of error handling, with semantics that more closely match
stack unwinding.
Errors that are thrown during the render phase unwind to the nearest
error boundary, like before. But rather than synchronously unmount the
children before retrying, we restart the failed subtree within the same
render phase. The failed children are still unmounted (as if all their
keys changed) but without an extra commit.
Commit phase errors are different. They work by scheduling an error on
the update queue of the error boundary. When we enter the render phase,
the error is popped off the queue. The rest of the algorithm is
the same.
This approach is designed to work for throwing non-errors, too, though
that feature is not implemented yet.
* Add experimental getDerivedStateFromCatch lifecycle
Fires during the render phase, so you can recover from an error within the same
pass. This aligns error boundaries more closely with try-catch semantics.
Let's keep this behind a feature flag until a future release. For now, the
recommendation is to keep using componentDidCatch. Eventually, the advice will
be to use getDerivedStateFromCatch for handling errors and componentDidCatch
only for logging.
* Reconcile twice to remount failed children, instead of using a boolean
* Handle effect immediately after its thrown
This way we don't have to store the thrown values on the effect list.
* ReactFiberIncompleteWork -> ReactFiberUnwindWork
* Remove startTime
* Remove TypeOfException
We don't need it yet. We'll reconsider once we add another exception type.
* Move replay to outer catch block
This moves it out of the hot path.
