Instead of createElement.
We should have done this when we initially released jsx-runtime but
better late than never. The general principle is that our tests should
be written using the most up-to-date idioms that we recommend for users,
except when explicitly testing an edge case or legacy behavior, like for
backwards compatibility.
Most of the diff is related to tweaking test output and isn't very
interesting.
I did have to workaround an issue related to component stacks. The
component stack logic depends on shared state that lives in the React
module. The problem is that most of our tests reset the React module
state and re-require a fresh instance of React, React DOM, etc. However,
the JSX runtime is not re-required because it's injected by the compiler
as a static import. This means its copy of the shared state is no longer
the same as the one used by React, causing any warning logged by the JSX
runtime to not include a component stack. (This same issue also breaks
string refs, but since we're removing those soon I'm not so concerned
about that.) The solution I went with for now is to mock the JSX runtime
with a proxy that re-requires the module on every function invocation. I
don't love this but it will have to do for now. What we should really do
is migrate our tests away from manually resetting the module state and
use import syntax instead.
Adds a feature flag to control whether the client cache function is just
a passthrough. before we land breaking changes for the next major it
will be off and then we can flag it on when we want to break it.
flag is off for OSS for now and on elsewhere (though the parent flag
enableCache is off in some cases)
Server Context was never documented, and has been deprecated in
https://github.com/facebook/react/pull/27424.
This PR removes it completely, including the implementation code.
Notably, `useContext` is removed from the shared subset, so importing it
from a React Server environment would now should be a build error in
environments that are able to enforce that.
Conceptually a Server Component in the tree is the same as a Client
Component.
When we render a Server Component with a key, that key should be used as
part of the reconciliation process to ensure the children's state are
preserved when they move in a set. The key of a child should also be
used to clear the state of the children when that key changes.
Conversely, if a Server Component doesn't have a key it should get an
implicit key based on the slot number. It should not inherit the key of
its children since the children don't know if that would collide with
other keys in the set the Server Component is rendered in.
A Client Component also has an identity based on the function's
implementation type. That mainly has to do with the state (or future
state after a refactor) that Component might contain. To transfer state
between two implementations it needs to be of the same state type. This
is not a concern for a Server Components since they never have state so
identity doesn't matter.
A Component returns a set of children. If it returns a single child,
that's the same as returning a fragment of one child. So if you
conditionally return a single child or a fragment, they should
technically reconcile against each other.
The simple way to do this is to simply emit a Fragment for every Server
Component. That would be correct in all cases. Unfortunately that is
also unfortunate since it bloats the payload in the common cases. It
also means that Fiber creates an extra indirection in the runtime.
Ideally we want to fold Server Component aways into zero cost on the
client. At least where possible. The common cases are that you don't
specify a key on a single return child, and that you do specify a key on
a Server Component in a dynamic set.
The approach in this PR treats a Server Component that returns other
Server Components or Lazy Nodes as a sequence that can be folded away.
I.e. the parts that don't generate any output in the RSC payload.
Instead, it keeps track of their keys on an internal "context". Which
gets reset after each new reified JSON node gets rendered.
Then we transfer the accumulated keys from any parent Server Components
onto the child element. In the simple case, the child just inherits the
key of the parent.
If the Server Component itself is keyless but a child isn't, we have to
add a wrapper fragment to ensure that this fragment gets the implicit
key but we can still use the key to reset state. This is unusual though
because typically if you keyed something it's because it was already in
a fragment.
In the case a Server Component is keyed but forks its children using a
fragment, we need to key that fragment so that the whole set can move
around as one. In theory this could be flattened into a parent array but
that gets tricky if something suspends, because then we can't send the
siblings early.
The main downside of this approach is that switching between single
child and fragment in a Server Component isn't always going to reconcile
against each other. That's because if we saw a single child first, we'd
have to add the fragment preemptively in case it forks later. This
semantic of React isn't very well known anyway and it might be ok to
break it here for pragmatic reasons. The tests document this
discrepancy.
Another compromise of this approach is that when combining keys we don't
escape them fully. We instead just use a simple `,` separated concat.
This is probably good enough in practice. Additionally, since we don't
encode the implicit 0 index slot key, you can move things around between
parents which shouldn't really reconcile but does. This keeps the keys
shorter and more human readable.
Partially reverting what has been removed in
https://github.com/facebook/react/pull/28186.
We need `'scheduler/tracing'` mock for React >= 16.8.
The error:
```
Invariant Violation: It is not supported to run the profiling version of a renderer (for example, `react-dom/profiling`) without also replacing the `scheduler/tracing` module with `scheduler/tracing-profiling`. Your bundler might have a setting for aliasing both modules. Learn more at http://fb.me/react-profiling
```
Validated by running regression tests for the whole version matrix:
```
./scripts/circleci/download_devtools_regression_build.js 16.0 --replaceBuild && node ./scripts/jest/jest-cli.js --build --project devtools --release-channel=experimental --reactVersion 16.0 --ci && ./scripts/circleci/download_devtools_regression_build.js 16.5 --replaceBuild && node ./scripts/jest/jest-cli.js --build --project devtools --release-channel=experimental --reactVersion 16.5 --ci && ./scripts/circleci/download_devtools_regression_build.js 16.8 --replaceBuild && node ./scripts/jest/jest-cli.js --build --project devtools --release-channel=experimental --reactVersion 16.8 --ci && ./scripts/circleci/download_devtools_regression_build.js 17.0 --replaceBuild && node ./scripts/jest/jest-cli.js --build --project devtools --release-channel=experimental --reactVersion 17.0 --ci && ./scripts/circleci/download_devtools_regression_build.js 18.0 --replaceBuild && node ./scripts/jest/jest-cli.js --build --project devtools --release-channel=experimental --reactVersion 18.0 --ci
```
Adding getter-functions for renderer implementations, which can be used
for jest tests. If we are testing against React with version < 18, we
are going to use legacy rendering, otherwise the concurrent one.
- Moving `act` implementation to a single getter-function, which is
based on React version we are testing RDT against.
- Removing unused mocks for `act`, which were designed for legacy
versions of React, validated with running tests against React 16 build.
## Summary
Add support for `useFormState` Hook fixing "Unsupported hook in the
react-debug-tools package: Missing method in Dispatcher: useFormState"
when inspecting components using `useFormState`
## How did you test this change?
- Added test to ReactHooksInspectionIntegration
- Added dedicated section for form actions to devtools-shell
## Summary
Add support for `useOptimistic` Hook fixing "Unsupported hook in the
react-debug-tools package: Missing method in Dispatcher: useOptimistic"
when inspecting components using `useOptimistic`
## How did you test this change?
- Added test following the same pattern as for `useDeferredValue`
Adds a new entrypoint for the production jsx-runtime when using
react-server condition. Currently the entrypoints are the same but in
the future we will potentially change the implementation of the runtime
in ways that can only be optimized for react-server constraints and we
want to have the entrypoint already separated so environments using it
will be pulling in the right version
## Summary
Converts `ReactTestUtils.renderIntoDocument` and `ReactDOM.findDOMNode`
to `ReactDOMClient.createRoot`
## How did you test this change?
`yarn test ReactElementValidator`
Not sure if this was also meant to test findDOMNode. But sounded like it
was more interested in the rendering aspect and findDOMNode was just
used as a utility. If we want to keep the findDOMNode tests, I'd just
rename it to a legacy test to indicate it needs to be flagged.
