### What?
Our
[docs](https://nextjs.org/docs/app/building-your-application/routing/parallel-routes#convention)
point out that `app/page.js` is equivalent to `app/@children/page.js`,
however in practice this is not the case, and causes type errors when
using `@children` slots as well as incorrect behavior when matching
catch-all routes.
### Why?
- When typechecking, `@children` slots would be added to the typeguard
file for the associated layout, resulting in duplicate identifiers for
the `children` prop
- When determining where to insert catchall slots, the `hasMatchedSlots`
check wasn't considering that the `@children` slot corresponds with the
page component, so matching another page would clobber the previous one.
### How?
- Filters out the `@children` slot when collecting slots for
typechecking
- Filters out the `@children` slot when running the `hasMatchedSlots`
function in the catch-all normalizer
Closes NEXT-1984
### Fixing a bug
I'm sorry, I have no idea how I managed to delete this, as I just copied
the code.
However, I had to figure out why the tests passed. When I test the
running application locally, it works as expected.
So, when a route is first used in a running production application in a
test, `ctx.fetchCache` is `undefined`. Therefore, the error rule does
not trigger on the first request, and the cache is successfully written.
This may result in artifacts in FetchCache in Vercel and possibly in
other parts of the code.
```ts
if (
ctx.fetchCache && // <- Undefined on first request
// we don't show this error/warning when a custom cache handler is being used
// as it might not have this limit
!this.hasCustomCacheHandler &&
JSON.stringify(data).length > 2 * 1024 * 1024
) {
if (this.dev) {
throw new Error(`fetch for over 2MB of data can not be cached`)
}
return
}
```
I'm 95% sure that this is a bug and it shouldn't work like this. I'll
look into this later and if there is an error, I'll put it into a task
and try to figure it out later.
Unfortunately, the
[test](7e028fb6d8/test/e2e/app-dir/app-static/app-static.test.ts (L3080))
from [previous PR](https://github.com/vercel/next.js/pull/59976) is not
working yet, although it is correct from my point of view. I think it
should be kept and the problem above should be fixed.
Co-authored-by: JJ Kasper <jj@jjsweb.site>
### What?
When relying on a `default` route as a fallback, greedier catch-all
segments in the application hierarchy would take precedence, causing
unexpected errors/matching behavior.
### Why?
When performing parallel route catch-all normalization, we push
potential catch-all matches to paths without considering that a path
might instead be matched by a `default` page. Because of this, the
catch-all take precedence and the app will not try and load the default.
For example, given this structure:
```
{
"/": ["/page"],
"/[[...catchAll]]": ["/[[...catchAll]]/page"],
"/nested/[foo]/[bar]": ["/nested/[foo]/[bar]/@slot/page"],
"/nested/[foo]/[bar]/[baz]": ["/nested/[foo]/[bar]/@slot/[baz]/page"],
}
```
(Where there's a `/nested/[foo]/[bar]/default.tsx`)
The route normalization logic would produce:
```
{
"/": ["/page"],
"/[[...catchAll]]": ["/[[...catchAll]]/page"],
"/nested/[foo]/[bar]": [
"/nested/[foo]/[bar]/@slot/page",
"/[[...catchAll]]/page",
],
"/nested/[foo]/[bar]/[baz]": [
"/nested/[foo]/[bar]/@slot/[baz]/page",
"/[[...catchAll]]/page",
],
}
```
This means that when building the `LoaderTree`, it won't ever try to
find the default for that segment. **This solution operates under the
assumption that if you defined a `default` at a particular layout
segment, you intend for that to render in place of a greedier
catch-all.** (Let me know if this is an incorrect assumption)
### How?
We can't safely normalize catch-all parallel routes without having
context about where the `default` segments are, so this updates
`appPaths` to be inclusive of default segments and then filters them
when doing anything relating to build/export to maintain existing
behavior. We use this information to check if an existing default exists
at the same segment level that we'd push the catch-all to. If one
exists, we don't push the catch-all. Otherwise we proceed as normal.
Closes NEXT-1987
### What?
Turbopack does not apply same transform for the react server components,
which makes missing lot of compilation error validation and custom
comments. PR refactors transform to be used in next-swc / turbopack
both, then apply it into turbopack.
There are still some of test cases are not passing, might need further
digging for the transform condition.
Closes PACK-2155
---------
Co-authored-by: Tim Neutkens <tim@timneutkens.nl>
- `useSearchParams` opts the client component subtree out of static
rendering (pre-rendering), not dynamic rendering. We recommend wrapping
the component that uses `useSearchParams` in a Suspense boundary to
allow client components above it to be statically rendered (part of the
initial HTML).
Closes: https://vercel.slack.com/archives/C03S9JCH2Q5/p1704398859737719
This fixes a case in the PPR navigations implementation where page data
was not being applied.
During a navigation, we compare the route trees of the old and new pages
to determine which layouts are shared. If the segment keys of two
layouts are the same, they are reused.
However, the server doesn't bother to assign segment keys to the leaf
segments (which we refer to as "page" segments) because they are never
part of a shared layout. It assigns all of them a special constant
(`__PAGE__`).
In the PPR implementation, I overlooked this and compared the segment
keys of all segments, including pages, not just shared layouts. So if
the only thing that changed during a navigation was the page data, and
not any parent layout, the client would fail to apply the navigation.
The fix is to add a special case for page segments before comparing
nested layouts. I also moved an existing special case for default pages,
since those are also leaf segments and are conceptually similar.
### Fixing a bug
### What?
Disable 2MB limit for custom incrementalCacheHandler
### Why?
The limit is necessary because `FetchCache` has a 2MB limit, but it
seems there was a miscommunication regarding the key coincidence, where
`fetchCache` is a flag indicating that the method is called from fetch,
rather than indicating that the `FetchCache` Provider is currently being
used.
We do not use Vercel, and as I understand it, we do not have the
opportunity to use this functionality.
In any case, it is more important for us to increase the limits, and in
some cases, using a file storage is even preferable.
### How?
I have created a flag that determines whether the use of `FetchCache` is
possible at least in theory - if no custom provider is passed, and
additionally configured it so that it is not an implementation of
`FetchCache` as a protection against special individuals (*like me :)*).
If everything is fine, I will write proper tests.
Also, I would like to recommend making `FileSystemCache` public (_i.e.
support it as public functionality_) so that it can be imported and
extended or simply used to fix only it.
Fixes#48324 (partially)
---------
Co-authored-by: JJ Kasper <jj@jjsweb.site>
This test was changed in https://github.com/vercel/next.js/pull/59074
because the latest sharp stopped working with yarn. However, we can
update these tests to use npm instead and continue testing the latest
sharp.
Closes NEXT-1986
Closes#57007
### What?
Errors were updated to MDX as part of
https://github.com/vercel/next.js/pull/52038, and as a part of this, the
`errors/manifest.json` file was removed.
This PR did not update the generators used to create new errors, causing
the error gen to...error 😄
This fixes the generator.
Fixes#57038
# What?
Added an error message when `generateStaticParams` returns an empty
array with `output:export`.
# Why?
To provide developers with clear feedback when `generateStaticParams` is
not used correctly.
# How?
Modified the condition checks around the use of `generateStaticParams`
to include a check for an empty array and added a corresponding error
message.
---------
Co-authored-by: Steven <steven@ceriously.com>
### What & Why?
When visiting a route that attempts to render a slot with no page & no default, the fallback behavior is to trigger a 404. However this can lead to a confusing development experience for complex parallel routing cases as you might not realize a default is missing, or which slot is causing the error.
Previous issues where this caused confusion:
- https://github.com/vercel/next.js/issues/51805
- https://github.com/vercel/next.js/issues/49569
### How?
This is a dev-only modification to track parallel slots that are using the default fallback (aka missing). When the `NotFoundBoundary` is triggered in development mode, this will log a warning about why it 404ed, along with a list of slot(s) that were determined to be missing.
### Future
We should eventually lift this into some sort of dev-only UI to help catch it when not monitoring the browser console (similar to the error overlay). However, this will require some design thought and isn't necessary for the first iteration.
Closes NEXT-1798
When trying to generate my SSG docs site I couldn't figure out why the
navigation links (`href="/about`) were not mapping to the generated
files (e.g. `/out/about.html)`.
`trailingSlash` was key to converting the files to
`/out/about/index.html` to make the SSG links work properly.
I've updated the trailingSlash docs to be clear how they affect SSG
mode.
It might also make sense to add this to the SSG guide as well.
Co-authored-by: Steven <steven@ceriously.com>
## What?
Currently there is a bug in Server Actions when you `fetch` as it uses
the same defaults (caching when not specified) as rendering, this causes
some issues as you want to read your writes in Server Actions.
This change adds the `no-store` default for Server Actions, you can
still override it by specifying `cache: 'force-cache'` for example, but
it defaults to `cache: 'no-store'`.
Fixes NEXT-1926
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---------
Co-authored-by: Zack Tanner <zacktanner@gmail.com>
