This uses the richer `serverAct` helper that we already use in other
tests.
This avoids using the `Scheduler`. We don't use that package on the
server so it doesn't make sense to simulate going through it.
Additionally, we really should be getting rid of it on the client too to
favor `postTask` polyfills.
## Summary
This PR bumps Flow all the way to the latest 0.245.2.
Most of the suppressions comes from Flow v0.239.0's change to include
undefined in the return of `Array.pop`.
I also enabled `react.custom_jsx_typing=true` and added custom jsx
typing to match the old behavior that `React.createElement` is
effectively any typed. This is necessary since various builtin
components like `React.Fragment` is actually symbol in the React repo
instead of `React.AbstractComponent<...>`. It can be made more accurate
by customizing the `React$CustomJSXFactory` type, but I will leave it to
the React team to decide.
## How did you test this change?
`yarn flow` for all the renderers
In https://github.com/facebook/react/pull/29491 I updated the work
scheduler for Flight to use microtasks to perform work when something
pings. This is useful but it does have some downsides in terms of our
ability to do task prioritization. Additionally the initial work is not
instantiated using a microtask which is inconsistent with how pings
work.
In this change I update the scheduling logic to use microtasks
consistently for prerenders and use regular tasks for renders both for
the initial work and pings.
## Overview
**Internal React repo tests only**
Depends on https://github.com/facebook/react/pull/28710
Adds three new assertions:
- `assertConsoleLogDev`
- `assertConsoleWarnDev`
- `assertConsoleErrorDev`
These will replace this pattern:
```js
await expect(async () => {
await expect(async () => {
await act(() => {
root.render(<Fail />)
});
}).toThrow();
}).toWarnDev('Warning');
```
With this:
```js
await expect(async () => {
await act(() => {
root.render(<Fail />)
});
}).toThrow();
assertConsoleWarnDev('Warning');
```
It works similar to our other `assertLog` matchers which clear the log
and assert on it, failing the tests if the log is not asserted before
the test ends.
## Diffs
There are a few improvements I also added including better log diffs and
more logging.
When there's a failure, the output will look something like:
<img width="655" alt="Screenshot 2024-04-03 at 11 50 08 AM"
src="https://github.com/facebook/react/assets/2440089/0c4bf1b2-5f63-4204-8af3-09e0c2d752ad">
Check out the test suite for snapshots of all the failures we may log.
Stacked on top of #28498 for test fixes.
### Don't Rethrow
When we started React it was 1:1 setState calls a series of renders and
if they error, it errors where the setState was called. Simple. However,
then batching came and the error actually got thrown somewhere else.
With concurrent mode, it's not even possible to get setState itself to
throw anymore.
In fact, all APIs that can rethrow out of React are executed either at
the root of the scheduler or inside a DOM event handler.
If you throw inside a React.startTransition callback that's sync, then
that will bubble out of the startTransition but if you throw inside an
async callback or a useTransition we now need to handle it at the hook
site. So in 19 we need to make all React.startTransition swallow the
error (and report them to reportError).
The only one remaining that can throw is flushSync but it doesn't really
make sense for it to throw at the callsite neither because batching.
Just because something rendered in this flush doesn't mean it was
rendered due to what was just scheduled and doesn't mean that it should
abort any of the remaining code afterwards. setState is fire and forget.
It's send an instruction elsewhere, it's not part of the current
imperative code.
Error boundaries never rethrow. Since you should really always have
error boundaries, most of the time, it wouldn't rethrow anyway.
Rethrowing also actually currently drops errors on the floor since we
can only rethrow the first error, so to avoid that we'd need to call
reportError anyway. This happens in RN events.
The other issue with rethrowing is that it logs an extra console.error.
Since we're not sure that user code will actually log it anywhere we
still log it too just like we do with errors inside error boundaries
which leads all of these to log twice.
The goal of this PR is to never rethrow out of React instead, errors
outside of error boundaries get logged to reportError. Event system
errors too.
### Breaking Changes
The main thing this affects is testing where you want to inspect the
errors thrown. To make it easier to port, if you're inside `act` we
track the error into act in an aggregate error and then rethrow it at
the root of `act`. Unlike before though, if you flush synchronously
inside of act it'll still continue until the end of act before
rethrowing.
I expect most user code breakages would be to migrate from `flushSync`
to `act` if you assert on throwing.
However, in the React repo we also have `internalAct` and the
`waitForThrow` helpers. Since these have to use public production
implementations we track these using the global onerror or process
uncaughtException. Unlike regular act, includes both event handler
errors and onRecoverableError by default too. Not just render/commit
errors. So I had to account for that in our tests.
We restore logging an extra log for uncaught errors after the main log
with the component stack in it. We use `console.warn`. This is not yet
ignorable if you preventDefault to the main error event. To avoid
confusion if you don't end up logging the error to console I just added
`An error occurred`.
### Polyfill
All browsers we support really supports `reportError` but not all test
and server environments do, so I implemented a polyfill for browser and
node in `shared/reportGlobalError`. I don't love that this is included
in all builds and gets duplicated into isomorphic even though it's not
actually needed in production. Maybe in the future we can require a
polyfill for this.
### Follow Ups
In a follow up, I'll make caught vs uncaught error handling be
configurable too.
---------
Co-authored-by: Ricky Hanlon <rickhanlonii@gmail.com>
This updates the Suspense fuzz tester to use `act` to recursively flush
timers instead of doing it manually.
This still isn't great because ideally the fuzz tester wouldn't fake
timers at all. It should resolve promises using a custom queue instead
of Jest's fake timer queue, like we've started doing in our other
Suspense tests (i.e. the `resolveText` pattern). That's because our
internal `act` API (not the public one, the one we use in our tests)
uses Jest's fake timer queue as a way to force Suspense fallbacks to
appear.
However I'm not interested in upgrading this test suite to a better
strategy right now because if I were writing a Suspense fuzzer today I
would probably use an entirely different approach. So this is just an
incremental improvement to make it slightly less decoupled to React
implementation details.
Added an explicit type to all $FlowFixMe suppressions to reduce
over-suppressions of new errors that might be caused on the same lines.
Also removes suppressions that aren't used (e.g. in a `@noflow` file as
they're purely misleading)
Test Plan:
yarn flow-ci
This adds an async gap to our internal implementation of `act` (the one
used by our repo, not the public API). Rather than call the provided
scope function synchronously when `act` is called, we call it in a
separate async task. This is an extra precaution to ensure that our
tests do not accidentally rely on work being queued synchronously,
because that is an implementation detail that we should be allowed to
change. We don't do this in the public version of `act`, though we maybe
should in the future, for the same rationale. That might be tricky,
though, because it could break existing tests.
This also fixes the issue where our internal `act` requires an async
function. You can pass it a regular function, too.
This is not a public API. We only use it for our internal tests, the
ones in this repo. Let's move it to this private package. Practically
speaking this will also let us use async/await in the implementation.
