This reverts commit ab4951fc03.
* Track "pending" and "suspended" ranges
A FiberRoot can have pending work at many distinct priorities. (Note: we
refer to these levels as "expiration times" to distinguish the concept
from Scheduler's notion of priority levels, which represent broad
categories of work. React expiration times are more granualar. They're
more like a concurrent thread ID, which also happens to correspond to a
moment on a timeline. It's an overloaded concept and I'm handwaving over
some of the details.)
Given a root, there's no convenient way to read all the pending levels
in the entire tree, i.e. there's no single queue-like structure that
tracks all the levels, because that granularity of information is not
needed by our algorithms. Instead we track the subset of information
that we actually need — most importantly, the highest priority level
that exists in the entire tree.
Aside from that, the other information we track includes the range of
pending levels that are known to be suspended, and therefore should not
be worked on.
This is a refactor of how that information is tracked, and what each
field represents:
- A *pending* level is work that is unfinished, or not yet committed.
This includes work that is suspended from committing.
`firstPendingTime` and `lastPendingTime` represent the range of
pending work. (Previously, "pending" was the same as "not suspended.")
- A *suspended* level is work that did not complete because data was
missing. `firstSuspendedTime` and `lastSuspendedTime` represent the
range of suspended work. It is a subset of the pending range. (These
fields are new to this commit.)
- `nextAfterSuspendedTime` represents the next known level that comes
after the suspended range.
This commit doesn't change much in terms of observable behavior. The one
change is that, when a level is suspended, React will continue working
on the next known level instead of jumping straight to the last pending
level. Subsequent commits will use this new structure for a more
substantial refactor for how tasks are scheduled per root.
* Get next expiration time from FiberRoot
Given a FiberRoot, we should be able to determine the next expiration
time that needs to be worked on, taking into account the levels that
are pending, suspended, pinged, and so on.
This removes the `expirationTime` argument from
`scheduleCallbackForRoot`, and renames it to `ensureRootIsScheduled` to
reflect the new signature. The expiration time is instead read from the
root using a new function, `getNextExpirationTimeToWorkOn`.
The next step will be to remove the `expirationTime` argument from
`renderRoot`, too.
* Don't bind expiration time to render callback
This is a fragile pattern because there's only meant to be a single
task per root, running at a single expiration time. Instead of binding
the expiration time to the render task, or closing over it, we should
determine the correct expiration time to work on using fields we
store on the root object itself.
This removes the "return a continuation" pattern from the
`renderRoot` function. Continuation handling is now handled by
the wrapper function, which I've renamed from `runRootCallback` to
`performWorkOnRoot`. That function is merely an entry point to
`renderRoot`, so I've also removed the callback argument.
So to sum up, at at the beginning of each task, `performWorkOnRoot`
determines which expiration time to work on, then calls `renderRoot`.
And before exiting, it checks if it needs to schedule another task.
* Update error recovery test to match new semantics
* Remove `lastPendingTime` field
It's no longer used anywhere
* Restart on update to already suspended root
If the work-in-progress root already suspended with a delay, then the
current render definitely won't finish. We should interrupt the render
and switch to the incoming update.
* Restart on suspend if return path has an update
Similar to the previous commit, if we suspend with a delay, and
something in the return path has a pending update, we should abort
the current render and switch to the update instead.
* Track the next unprocessed level globally
Instead of backtracking the return path. The main advantage over the
backtracking approach is that we don't have to backtrack from the source
fiber. (The main disadvantages are that it requires another module-level
variable, and that it could include updates from unrelated
sibling paths.)
* Re-arrange slightly to prevent refactor hazard
It should not be possible to perform any work on a root without
calling `ensureRootIsScheduled` before exiting. Otherwise, we could
fail to schedule a callback for pending work and the app could freeze.
To help prevent a future refactor from introducing such a bug, this
change makes it so that `renderRoot` is always wrapped in try-finally,
and the `finally` block calls `ensureRootIsScheduled`.
* Remove recursive calls to `renderRoot`.
There are a few leftover cases where `renderRoot` is called recursively.
All of them are related to synchronously flushing work before its
expiration time.
We can remove these calls by tracking the last expired level on the
root, similar to what we do for other types of pending work, like pings.
* Remove argument from performSyncWorkOnRoot
Read the expiration time from the root, like we do
in performConcurrentWorkOnRoot.
* Track "pending" and "suspended" ranges
A FiberRoot can have pending work at many distinct priorities. (Note: we
refer to these levels as "expiration times" to distinguish the concept
from Scheduler's notion of priority levels, which represent broad
categories of work. React expiration times are more granualar. They're
more like a concurrent thread ID, which also happens to correspond to a
moment on a timeline. It's an overloaded concept and I'm handwaving over
some of the details.)
Given a root, there's no convenient way to read all the pending levels
in the entire tree, i.e. there's no single queue-like structure that
tracks all the levels, because that granularity of information is not
needed by our algorithms. Instead we track the subset of information
that we actually need — most importantly, the highest priority level
that exists in the entire tree.
Aside from that, the other information we track includes the range of
pending levels that are known to be suspended, and therefore should not
be worked on.
This is a refactor of how that information is tracked, and what each
field represents:
- A *pending* level is work that is unfinished, or not yet committed.
This includes work that is suspended from committing.
`firstPendingTime` and `lastPendingTime` represent the range of
pending work. (Previously, "pending" was the same as "not suspended.")
- A *suspended* level is work that did not complete because data was
missing. `firstSuspendedTime` and `lastSuspendedTime` represent the
range of suspended work. It is a subset of the pending range. (These
fields are new to this commit.)
- `nextAfterSuspendedTime` represents the next known level that comes
after the suspended range.
This commit doesn't change much in terms of observable behavior. The one
change is that, when a level is suspended, React will continue working
on the next known level instead of jumping straight to the last pending
level. Subsequent commits will use this new structure for a more
substantial refactor for how tasks are scheduled per root.
* Get next expiration time from FiberRoot
Given a FiberRoot, we should be able to determine the next expiration
time that needs to be worked on, taking into account the levels that
are pending, suspended, pinged, and so on.
This removes the `expirationTime` argument from
`scheduleCallbackForRoot`, and renames it to `ensureRootIsScheduled` to
reflect the new signature. The expiration time is instead read from the
root using a new function, `getNextExpirationTimeToWorkOn`.
The next step will be to remove the `expirationTime` argument from
`renderRoot`, too.
* Don't bind expiration time to render callback
This is a fragile pattern because there's only meant to be a single
task per root, running at a single expiration time. Instead of binding
the expiration time to the render task, or closing over it, we should
determine the correct expiration time to work on using fields we
store on the root object itself.
This removes the "return a continuation" pattern from the
`renderRoot` function. Continuation handling is now handled by
the wrapper function, which I've renamed from `runRootCallback` to
`performWorkOnRoot`. That function is merely an entry point to
`renderRoot`, so I've also removed the callback argument.
So to sum up, at at the beginning of each task, `performWorkOnRoot`
determines which expiration time to work on, then calls `renderRoot`.
And before exiting, it checks if it needs to schedule another task.
* Update error recovery test to match new semantics
* Remove `lastPendingTime` field
It's no longer used anywhere
* Restart on update to already suspended root
If the work-in-progress root already suspended with a delay, then the
current render definitely won't finish. We should interrupt the render
and switch to the incoming update.
* Restart on suspend if return path has an update
Similar to the previous commit, if we suspend with a delay, and
something in the return path has a pending update, we should abort
the current render and switch to the update instead.
* Track the next unprocessed level globally
Instead of backtracking the return path. The main advantage over the
backtracking approach is that we don't have to backtrack from the source
fiber. (The main disadvantages are that it requires another module-level
variable, and that it could include updates from unrelated
sibling paths.)
* Re-arrange slightly to prevent refactor hazard
It should not be possible to perform any work on a root without
calling `ensureRootIsScheduled` before exiting. Otherwise, we could
fail to schedule a callback for pending work and the app could freeze.
To help prevent a future refactor from introducing such a bug, this
change makes it so that `renderRoot` is always wrapped in try-finally,
and the `finally` block calls `ensureRootIsScheduled`.
* Remove recursive calls to `renderRoot`.
There are a few leftover cases where `renderRoot` is called recursively.
All of them are related to synchronously flushing work before its
expiration time.
We can remove these calls by tracking the last expired level on the
root, similar to what we do for other types of pending work, like pings.
* Remove argument from performSyncWorkOnRoot
Read the expiration time from the root, like we do
in performConcurrentWorkOnRoot.
Improved warning whenever lower priority events (ex. data fetching, page load) happen during a high priority update (ex. hover/click events) to include:
1.) Name of component that triggered the high priority update or
2.) Information that the update was triggered on the root
* Rename ReactFiberScheduler to ReactFiberWorkLoop
The scheduling part is mostly extracted out to the scheduler package.
What's remaining is mostly around the loop around each section of work.
I name it something with Work in it because it's very related to the
BeginWork, CompleteWork and UnwindWork sections.
* Extract throwException from UnwindWork
Our throwing works more like algebraic effects in that it's a separate
phase where we find a handler and we later unwind.
* Add suspendIfNeeded API and a global scope to track it
Adds a "current" suspense config that gets applied to all updates scheduled
during the current scope.
I suspect we might want to add other types of configurations to the "batch"
so I called it the "batch config".
This works across renderers/roots but they won't actually necessarily go
into the same batch.
* Add the suspenseConfig to all updates created during this scope
* Compute expiration time based on the timeout of the suspense config
* Track if there was a processed suspenseConfig this render pass
We'll use this info to suspend a commit for longer when necessary.
* Mark suspended states that should be avoided as a separate flag
This lets us track which renders we want to suspend for a short time vs
a longer time if possible.
* Suspend until the full expiration time if something asked to suspend
* Reenable an old test that we can now repro again
* Suspend the commit even if it is complete if there is a minimum delay
This can be used to implement spinners that don't flicker if the data
and rendering is really fast.
* Default timeoutMs to low pri expiration if not provided
This is a required argument in the type signature but people may not
supply it and this is a user facing object.
* Rename to withSuspenseConfig and drop the default config
This allow opting out of suspending in some nested scope.
A lot of time when you use this function you'll use it with high level
helpers. Those helpers often want to accept some additional configuration
for suspense and if it should suspend at all. The easiest way is to just
have the api accept null or a suspense config and pass it through. However,
then you have to remember that calling suspendIfNeeded has a default.
It gets simpler by just saying tat you can pass the config. You can have
your own default in user space.
* Track the largest suspense config expiration separately
This ensures that if we've scheduled lower pri work that doesn't have a
suspenseConfig, we don't consider its expiration as the timeout.
* Add basic tests for functionality using each update mechanism
* Fix issue when newly created avoided boundary doesn't suspend with delay
* Add test for loading indicator with minLoadingDurationMs option
* Track the earliest event time in this render
Rebase
* Track the time of the fallback being shown as an event time
When we switch back from fallback to content, we made progress and we track
the time from when we showed the fallback in the first place as the
last time we made progress.
* Don't retry if synchronous
* Only suspend when we switch to fallback mode
This ensures that we don't resuspend unnecessarily if we're just retrying
the same exact boundary again. We can still unnecessarily suspend
for nested boundaries.
* Rename timedOutAt to fallbackExpirationTime
* Account for suspense in devtools suspense test
* Make readContext() in Hooks DEV-only warning
* Warn about readContext() during class render-phase setState()
* Warn on readContext() in SSR inside useMemo and useReducer
* Make all Hooks-in-Hooks warnings DEV-only
* Rename stashContextDependencies
* Clean up warning state on errors
* Introduce elementType field
This will be used to store the wrapped type of an element. E.g. pure and
lazy.
The existing type field will be used for the unwrapped type within them.
* Store the unwrapped type on the type field of lazy components
* Use the raw tags for lazy components
Instead, we check if the elementType and type are equal to test if
we need to resolve props. This is slightly slower in the normal case
but will yield less code and branching.
* Clean up lazy branches
* Collapse work tag numbering
* Split IndeterminateComponent out from Lazy
This way we don't have to check the type in a hacky way in the
indeterminate path. Also, lets us deal with lazy that resolves to
indeterminate and such.
* Missing clean up in rebase
* Accept promise as element type
On the initial render, the element will suspend as if a promise were
thrown from inside the body of the unresolved component. Siblings should
continue rendering and if the parent is a Placeholder, the promise
should be captured by that Placeholder.
When the promise resolves, rendering resumes. If the resolved value
has a `default` property, it is assumed to be the default export of
an ES module, and we use that as the component type. If it does not have
a `default` property, we use the resolved value itself.
The resolved value is stored as an expando on the promise/thenable.
* Use special types of work for lazy components
Because reconciliation is a hot path, this adds ClassComponentLazy,
FunctionalComponentLazy, and ForwardRefLazy as special types of work.
The other types are not supported, but wouldn't be placed into a
separate module regardless.
* Resolve defaultProps for lazy types
* Remove some calls to isContextProvider
isContextProvider checks the fiber tag, but it's typically called after
we've already refined the type of work. We should get rid of it. I
removed some of them in the previous commit, and deleted a few more
in this one. I left a few behind because the remaining ones would
require additional refactoring that feels outside the scope of this PR.
* Remove getLazyComponentTypeIfResolved
* Return baseProps instead of null
The caller compares the result to baseProps to see if anything changed.
* Avoid redundant checks by inlining getFiberTagFromObjectType
* Move tag resolution to ReactFiber module
* Pass next props to update* functions
We should do this with all types of work in the future.
* Refine component type before pushing/popping context
Removes unnecessary checks.
* Replace all occurrences of _reactResult with helper
* Move shared thenable logic to `shared` package
* Check type of wrapper object before resolving to `default` export
* Return resolved tag instead of reassigning
* Store list of contexts on the fiber
Currently, context can only be read by a special type of component,
ContextConsumer. We want to add support to all fibers, including
classes and functional components.
Each fiber may read from one or more contexts. To enable quick, mono-
morphic access of this list, we'll store them on a fiber property.
* Context.unstable_read
unstable_read can be called anywhere within the render phase. That
includes the render method, getDerivedStateFromProps, constructors,
functional components, and context consumer render props.
If it's called outside the render phase, an error is thrown.
* Remove vestigial context cursor
Wasn't being used.
* Split fiber.expirationTime into two separate fields
Currently, the `expirationTime` field represents the pending work of
both the fiber itself — including new props, state, and context — and of
any updates in that fiber's subtree.
This commit adds a second field called `childExpirationTime`. Now
`expirationTime` only represents the pending work of the fiber itself.
The subtree's pending work is represented by `childExpirationTime`.
The biggest advantage is it requires fewer checks to bailout on already
finished work. For most types of work, if the `expirationTime` does not
match the render expiration time, we can bailout immediately without
any further checks. This won't work for fibers that have
`shouldComponentUpdate` semantics (class components), for which we still
need to check for props and state changes explicitly.
* Performance nits
Optimize `readContext` for most common case
* Use %s in the console calls
* Add shared/warningWithStack
* Convert some warning callsites to warningWithStack
* Use warningInStack in shared utilities and remove unnecessary checks
* Replace more warning() calls with warningWithStack()
* Fixes after rebase + use warningWithStack in react
* Make warning have stack by default; warningWithoutStack opts out
* Forbid builds that may not use internals
* Revert newly added stacks
I changed my mind and want to keep this PR without functional changes. So we won't "fix" any warnings that are already missing stacks. We'll do it in follow-ups instead.
* Fix silly find/replace mistake
* Reorder imports
* Add protection against warning argument count mismatches
* Address review
* Use global state for `hasForceUpdate` instead of persisting to queue
Fixes a bug where `hasForceUpdate` was not reset on commit.
Ideally we'd use a tuple and return `hasForceUpdate` from
`processUpdateQueue`.
* Remove underscore and add comment
* Remove temporary variables
* Decouple update queue from Fiber type
The update queue is in need of a refactor. Recent bugfixes (#12528) have
exposed some flaws in how it's modeled. Upcoming features like Suspense
and [redacted] also rely on the update queue in ways that weren't
anticipated in the original design.
Major changes:
- Instead of boolean flags for `isReplace` and `isForceUpdate`, updates
have a `tag` field (like Fiber). This lowers the cost for adding new
types of updates.
- Render phase updates are special cased. Updates scheduled during
the render phase are dropped if the work-in-progress does not commit.
This is used for `getDerivedStateFrom{Props,Catch}`.
- `callbackList` has been replaced with a generic effect list. Aside
from callbacks, this is also used for `componentDidCatch`.
* Remove first class UpdateQueue types and use closures instead
I tried to avoid this at first, since we avoid it everywhere else in the Fiber
codebase, but since updates are not in a hot path, the trade off with file size
seems worth it.
* Store captured errors on a separate part of the update queue
This way they can be reused independently of updates like
getDerivedStateFromProps. This will be important for resuming.
* Revert back to storing hasForceUpdate on the update queue
Instead of using the effect tag. Ideally, this would be part of the
return type of processUpdateQueue.
* Rename UpdateQueue effect type back to Callback
I don't love this name either, but it's less confusing than UpdateQueue
I suppose. Conceptually, this is usually a callback: setState callbacks,
componentDidCatch. The only case that feels a bit weird is Timeouts,
which use this effect to attach a promise listener. I guess that kinda
fits, too.
* Call getDerivedStateFromProps every render, even if props did not change
Rather than enqueue a new setState updater for every props change, we
can skip the update queue entirely and merge the result into state at
the end. This makes more sense, since "receiving props" is not an event
that should be observed. It's still a bit weird, since eventually we do
persist the derived state (in other words, it accumulates).
* Store captured effects on separate list from "own" effects (callbacks)
For resuming, we need the ability to discard the "own" effects while
reusing the captured effects.
* Optimize for class components
Change `process` and `callback` to match the expected payload types
for class components. I had intended for the update queue to be reusable
for both class components and a future React API, but we'll likely have
to fork anyway.
* Only double-invoke render phase lifecycles functions in DEV
* Use global state to track currently processing queue in DEV
Andrew Clark
lunaruan
Sebastian Markbåge
Sebastian Markbåge
Dan Abramov
Carl Mungazi
Sophie Alpert
Héctor Ramos
Andrew Clark
Ruud Burger