This leverages [fetch
priority](https://developer.mozilla.org/en-US/docs/Web/API/Request/Request#priority)
to ensure automatic prefetching as a result of visiting a page is sent
with "low" priority, to signal to the browser it can prioritize more
important work necessary for rendering the page.
A "temporary" prefetch (ie one that is created when there wasn't an
existing prefetch cache entry on navigation) will use a "high" priority
because it's critical to the navigation event.
All other cases will be "auto" which is the current default.
## History
When we added `priority` prop to `next/image`, there was no
`fetchPriority` so we instead used this to preload the image in the
head.
Then when browsers added support `fetchPriority`, we automatically added
`fetchPriority=high` when `priority={true}` to signal to the browser
that this was a high priority image. This priority is added to the img
and the preload.
However, we saw cases where images are blocking critical css. Per
@gnoff:
> React currently prioritizes font preloads then high priority images,
then css in the initial page load
Due to these changes in React (aka Float), we should no longer set
`fetchPriority=high`, although the user can still manually add that prop
if needed.
### What
* Warn with next.js when users customized `experimental.esmExternals`
value
* Add telemetry tracking on the customization usage for that flag. 0 for
no customization, 1 for used non-default customized value
### Why
`esmExternals` ideally can just remain as default value `true` which
Next.js can handle the customization properly. Since next.js app router
also supports it on canary now we're adding a warning to users that
don't modify `esmExternals` option as it could affect module resolution
on ESM packages.
### Why?
It could be confusing between `...` and `…`, which the later is actually
a single character.
### How?
We throw if we detect `…` instead of `...`.
The Image Optimization API currently uses `parseInt()` for `w` and `q`
query string parameters.
This doesn't handle floats as you might expect and instead coerces, for
example `parseInt('99.9') === 99`.
This PR changes the runtime to match the build time validation and only
accept integers for `w` and `q`.
When a server action responds with something other than an RSC response,
we currently silently ignore the error and it doesn't get propagated to
any rejection handlers.
This adjusts the handling so that if the server action response is a
non-successful status code, we reject the server action promise. If the
error is `text/plain`, we'll automatically propagate the text content as
the error text. Otherwise, the promise is rejected with a fallback
message.
Fixes some possible race conditions by adding a few delays to the
navigation test to ensure that we wait for hydration to occur and
prefetches to finish.
Previously, when the provided postponed state was corrupted, the render
failed which resulted in a hydration error. Instead, when the postponed
state is corrupted, we send the resume stream just for the hydration
where it'll attempt to render client side with the data that's already
available.
### What
Reland #64716
Removing the Suspense boundary on top of `next/dynamic` by default, make
it as `React.lazy` component with preloading CSS feature.
* Remove `suspense` option in `next/dynamic` since it's already
deprecated for a while
* Remove the default loading in app router implmentation of
`next/dynamic`
### Why
Extra Suspense boundary is causing extra useless rendering. For SSR, it
shouldn't render `loading` by default
Related: #64060
Related: #64687
Closes
[NEXT-3074](https://linear.app/vercel/issue/NEXT-3074/app-router-content-flickering-with-reactcreatecontext-and-nextdynamic)
This is sort of a breaking change, since removing the Suspense boundary
on top of `next/dynamic` by default. If there's error happening in side
the dynamic component you need to wrap an extra Suspense boundary on top
of it
### What
Add isEdgeRendering check condition for rewrite logic in edge adpator
Fixes#66837
Closes NEXT-3545
### Why
From headers `x-middleware-rewrite`, it's still relative url `/rewrite`,
reconstructing the url will lead to crash as it doesn't contain host.
### What
Render noindex into a flight data and rsc payload when page path is
`/404`
### Why
When it's static generation, noindex is not rendered due to the
statusCode from mock request is 200, but we can relying on the pagePath
as `/404` page should always contain `nonidex`
We were missing the noindex before for flight generation, now we'll
render it when it's 404 page.
### What
Show the full `pagePath` information for missing default component app
router convention files.
Move runtime error tests from `rsc-build-errors.test.ts` to the new test
`test/development/acceptance-app/undefined-default-export.test.ts`
### Why
Previously we only log `segment` which could be `[slug]` that is not
enough useful for users to locate the bad defined component
This test was failing when deployed with _"Unsupported URL Type
"link:"._
This tweaks the linking behavior when deployed. I wasn't able to get
this test to pass when changing both `start` and deploy to use `link`.
When accessing search params, we only track dynamic access during static
generation. This has implications on fetch caching, because the fetch
cache relies on hints set during render that it's in a dynamic scope. In
15, this would signal that it should not attempt to cache the fetch at
all. In 14, this could impact the heuristic that bails from fetch cache
if dynamic access came before certain requests types, e.g. POSTs.
Currently webpack would be incorrectly used when some of the
experimental options for builds were enabled. For example
`parallelServerCompiles` and `parallelServerBuildTraces`. This ensures
Turbopack is always used when it's specified to be used.
Fixes around 100 Turbopack build tests
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### What?
### Why?
### How?
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...with `assertHasRedbox` and `assertNoRedbox`.
`hasRedbox()` has a hardcoded timeout of 5s that is only required for
the negative assertion.
Instead, we now have dedicated assertions for the positive
(`assertHasRedbox`) and negative case (`assertNoRedbox`).
The negative assertion still has the hardcoded timeout.
But the positive assertion just retries until we find the Redbox.
This speeds up tests using the positive assertion.
Removing `hasRedbox` also uncovered some unused expressions e.g. `await
hasRedbox(browser)`.
These expressions probably wanted to use `expect(await
hasRedbox(browser)).toBe(true)
## What?
This PR adds an option to use `sass-embedded`.
## Why?
For large projects sass-embedded improves SCSS compilation time by over
50%.
See also https://github.com/vercel/next.js/discussions/36160
## How?
Added a sassOption `implementation` to configure the sass-loader which
Sass implementation to use.
See also https://www.npmjs.com/package/sass-loader#implementation
I think this a similar approach to what is done for `additionalData`.
## Additional notes
In order to support `sass-embedded`, `sass-loader` is upgraded to
12.6.0.
---------
Co-authored-by: Zack Tanner <1939140+ztanner@users.noreply.github.com>
### What?
Writes the async flag to the client reference manifest to support ESM
externals in app dir.
The `app-ssr` context can't have esm externals as that might cause a
module to be async in ssr but not on the client.
Closes PACK-2967
Fixes#64525
### What
app-dir `metadata.test.ts` is pretty big and includes a lot of erroring
tests and navigation tests. Breaking them into smaller suites to avoid
the erroring on effect on others.
- metadata
- metadata-navigation
- metadata-thrown
Moved the metadata testing utils into `next-test-utils` for sharing
purpose.
Moved the hmr test to the bottom to avoid flakyness.
When performing a redirect() with an absolute path, action-handler
attempts to detect whether the resource is hosted by NextJS. If we
believe it is, we then attempt to stream it.
Previously we were not accounting for basePath which caused absolute
redirects to resources on the same host, but not underneath the
basePath, to be resolved by NextJS. Since the resource is outside the
basePath we resolve a 404 page which returns back as `text/x-component`
and is thus streamed back to the client within the original POST
request.
This PR adds a check for the presence of the basePath within absolute
redirect URLs. This fixes the above problem.
fixes#64413fixes#64557
---------
Signed-off-by: Chris Frank <chris@cfrank.org>
Co-authored-by: JJ Kasper <jj@jjsweb.site>
This refactors our handling of passing routing information to the render
logic via headers which is legacy from when we had separate routing and
render workers. Now this will just attach this meta in our normal
request meta handling which is more consistent and type safe.
This handles the case where a middleware rewrite causes us to fail to
resolve the correct dynamic route params for an action sent to a
prerendered ISR path since the matched path wouldn't be the original
source path like we expect and instead is the prerendered path so we
need to parse the params out instead.
---------
Co-authored-by: Zack Tanner <1939140+ztanner@users.noreply.github.com>
