Fixes a bug where lower priority updates on a components wrapped with
`memo` are sometimes left dangling in the queue without ever being
processed, if they are preceded by a higher priority bailout.
Cause
-----
The pending update priority field is cleared at the beginning of
`beginWork`. If there is remaining work at a lower priority level, it's
expected that it will be accumulated on the work-in-progress fiber
during the begin phase.
There's an exception where this assumption doesn't hold:
SimpleMemoComponent contains a bailout that occurs *before* the
component is evaluated and the update queues are processed, which means
we don't accumulate the next priority level. When we complete the fiber,
the work loop is left to believe that there's no remaining work.
Mitigation
----------
Since this only happens in a single case, a late bailout in
SimpleMemoComponent, I've mitigated the bug in that code path by
restoring the original update priority from the current fiber.
This same case does not apply to MemoComponent, because MemoComponent
fibers do not contain hooks or update queues; rather, they wrap around
an inner fiber that may contain those. However, I've added a test case
for MemoComponent to protect against a possible future regression.
Possible next steps
-------------------
We should consider moving the update priority assignment in `beginWork`
out of the common path and into each branch, to avoid similar bugs in
the future.
Adds a feature flag for when React.jsx warns you about spreading a key into jsx. It's false for all builds, except as a dynamic flag for fb/www.
I also included the component name in the warning.
This warning already exists for class components, but not for functions.
It does not apply to render phase updates to the same component, which
have special semantics that we do support.
Our current lint config assumes a browser environment, which means it won't warn you if you use a variable like `name` without declaring it earlier. This imports the same list as the one used by create-react-app, and enables it against our codebase.
* Re-throw errors thrown by the renderer at the root
React treats errors thrown at the root as a fatal because there's no
parent component that can capture it. (This is distinct from an
"uncaught error" that isn't wrapped in an error boundary, because in
that case we can fall back to deleting the whole tree -- not great, but
at least the error is contained to a single root, and React is left in a
consistent state.)
It turns out we didn't have a test case for this path. The only way it
can happen is if the renderer's host config throws. We had similar test
cases for host components, but none for the host root.
This adds a new test case and fixes a bug where React would keep
retrying the root because the `workInProgress` pointer was not advanced
to the next fiber. (Which in this case is `null`, since it's the root.)
We could consider in the future trying to gracefully exit from certain
types of root errors without leaving React in an inconsistent state. For
example, we should be able to gracefully exit from errors thrown in the
begin phase. For now, I'm treating it like an internal invariant and
immediately exiting.
* Add comment
* Split recent passive effects changes into 2 flags
Separate flags can now be used to opt passive effects into:
1) Deferring destroy functions on unmount to subsequent passive effects flush
2) Running all destroy functions (for all fibers) before create functions
This allows us to test the less risky feature (2) separately from the more risky one.
* deferPassiveEffectCleanupDuringUnmount is ignored unless runAllPassiveEffectDestroysBeforeCreates is true
Before attempting to land an expiration times refactor, I want to see
if this particular change will impact performance (either positively
or negatively). I will test this with a GK.
This babel transform is a fork of the @babel/plugin-transform-react-jsx transform and is for experimentation purposes only. We don't plan to own this code in the future, and we will upstream this to Babel at some point once we've proven out the concept.
As per the RFC to simplify element creation, we want to add the ability to auto import "react' directly from the babel plugin. This commit updates the babel plugin with two options:
1.) importSource: The React module to import from. Defaults to react.
2.) autoImport: The type of import. Defaults to none.
- none: Does not import React. JSX compiles to React.jsx etc.
- namespace: import * as _react from "react";. JSX compiles to _react.jsx etc.
- default: import _default from "react"; JSX compiles to _default.jsx etc.
- namedExports: import {jsx as _jsx} from "react"; JSX compiles to _jsx etc.
- require: var _react = _interopRequireWildcard(require("react"));. jSX compiles to _react.jsx etc.
namespace, default, and namedExports can only be used when sourceType: module and require can only be used when sourceType: script.
It also adds two pragmas (jsxAutoImport and jsxImportSource) that allow users to specify autoImport and importSource in the docblock.
* Build both stable and experimental WWW builds
* Flip already experimental WWW flags to true
* Remove FB-specific internals from modern FB builds
We think we're not going to need these.
* Disable classic features in modern WWW builds
* Disable legacy ReactDOM API for modern WWW build
* Don’t include user timing in prod
* Fix bad copy paste and add missing flags to test renderer
* Add testing WWW feature flag file
We need it because WWW has a different meaning of experimental now.
This section is empty, and imo isn't really helpful in React's changelog. I'm honestly not sure why this is even here? Figured I'd start a discussion with a PR, or we can remove it right now.
* Flush all passive destroy fns before calling create fns
Previously we only flushed destroy functions for a single fiber.
The reason this is important is that interleaving destroy/create effects between sibling components might cause components to interfere with each other (e.g. a destroy function in one component may unintentionally override a ref value set by a create function in another component).
This PR builds on top of the recently added deferPassiveEffectCleanupDuringUnmount kill switch to separate passive effects flushing into two separate phases (similar to layout effects).
* Change passive effect flushing to use arrays instead of lists
This change offers a small advantage over the way we did things previous: it continues invoking destroy functions even after a previous one errored.
Dan Abramov
Andrew Clark
Kunuk Nykjær
Sunil Pai
Dominic Gannaway
Eli White
Brian Vaughn
Moji Izadmehr
Ryota Murakami
Haseeb Furkhan Mohammed
Will Douglas
Luna Ruan
haseeb
Jesse Katsumata
Sophie Alpert
cutjavascript