The "next" prerelease channel represents what will be published the next
time we do a stable release. We publish a new "next" release every day
using a timed CI workflow.
When we introduced this prerelease channel a few years ago, another name
we considered was "canary". But I proposed "next" instead to create a
greater distinction between this channel and the "experimental" channel
(which is published at the same cadence, but includes extra experimental
features), because some other projects use "canary" to refer to releases
that are more unstable than how we would use it.
The main downside of "next" is someone might mistakenly assume the name
refers to Next.js. We were aware of this risk at the time but didn't
think it would be an issue in practice.
However, colloquially, we've ended up referring to this as the "canary"
channel anyway to avoid precisely that confusion.
So after further discussion, we've agreed to rename to "canary".
This affects the label used in the version string (e.g.
`18.3.0-next-a1c2d3e4` becomes `18.3.0-canary-a1c2d3e4`) as well as the
npm dist tags used to publish the releases. For now, I've chosen to
publish the canaries using both `@canary` and `@next` dist tags, so that
downstream consumers who might depend on `@next` have time to adjust. We
can remove that later after the change has been communicated.
* Move useSyncExternalStore shim to a nested entrypoint
Also renames `useSyncExternalStoreExtra` to
`useSyncExternalStoreWithSelector`.
- 'use-sync-external-store/shim' -> A shim for `useSyncExternalStore`
that works in React 16 and 17 (any release that supports hooks). The
module will first check if the built-in React API exists, before
falling back to the shim.
- 'use-sync-external-store/with-selector' -> An extended version of
`useSyncExternalStore` that also supports `selector` and `isEqual`
options. It does _not_ shim `use-sync-external-store`; it composes the
built-in React API. **Use this if you only support 18+.**
- 'use-sync-external-store/shim/with-selector' -> Same API, but it
composes `use-sync-external-store/shim` instead. **Use this for
compatibility with 16 and 17.**
- 'use-sync-external-store' -> Re-exports React's built-in API. Not
meant to be used. It will warn and direct users to either the shim or
the built-in API.
* Upgrade useSyncExternalStore to alpha channel
Change format of @next and @experimental release versions from <number>-<sha> to <number>-<sha>-<date> to make them more human readable. This format still preserves the ability for us to easily map a version number to the changes it contains, while also being able to more easily know at a glance how recent a release is.
This does not mean that a release of 18.0 is imminent, only that the
main branch includes breaking changes.
Also updates the versioning scheme of the `@next` channel to include
the upcoming semver number, as well as the word "alpha" to indicate the
stability of the release.
- Before: 0.0.0-e0d9b28999
- After: 18.0.0-alpha-e0d9b28999
The versioning scheme for `@next` releases does not include semver
information. Like `@experimental`, the versions are based only on the
hash, i.e. `0.0.0-<commit_sha>`. The reason we do this is to prevent
the use of a tilde (~) or caret (^) to match a range of
prerelease versions.
For `@experimental`, I think this rationale still makes sense — those
releases are very unstable, with frequent breaking changes. But `@next`
is not as volatile. It represents the next stable release. So, I think
we can afford to include an actual verison number at the beginning of
the string instead of `0.0.0`.
We can also add a label that indicates readiness of the upcoming
release, like "alpha", "beta", "rc", etc.
To prepare for this the new versioning scheme, I updated the build
script. However, **this PR does not enable the new versioning scheme
yet**. I left a TODO above the line that we'll change once we're ready.
We need to specify the expected next version numbers for each package,
somewhere. These aren't encoded anywhere today — we don't specify
version numbers until right before publishing to `@latest`, using an
interactive script: `prepare-release-from-npm`.
Instead, what we can do is track these version numbers in a module. I
added `ReactVersions.js` that acts as the single source of truth for
every package's version. The build script uses this module to build the
`@next` packages.
In the future, I want to start building the `@latest` packages the same
way we do `@next` and `@experimental`. (What we do now is download a
`@next` release from npm and swap out its version numbers.) Then we
could run automated tests in CI to confirm the packages are releasable,
instead of waiting to verify that right before publish.
Andrew Clark