Fix NEXT-2165
### What?
Addresses the limitation of #60240, where a dummy `default` file is
required in parallel route child slot to prevent errors in dev server
rendering (`TypeError: Cannot read properties of undefined (reading
'clientModules')`) as well as errors in build and deploy (`Error:
ENOENT: no such file or directory, lstat
‘/vercel/path0/.next/server/app/parallel-route/[section]/@part/[partSlug]/page_client-reference-manifest.js’`)
Without the `default.tsx`, builds and deployments will fail with:
<img width="956" alt="CleanShot 2024-01-18 at 02 12 36@2x"
src="https://github.com/vercel/next.js/assets/179761/80ba61bd-6ec0-4b16-a393-dc9375227e19">
local dev server will also crash with:
<img width="986" alt="CleanShot 2024-01-18 at 02 13 19@2x"
src="https://github.com/vercel/next.js/assets/179761/cc500a32-b2f8-47b4-999e-e57cf5141b2f">
> TypeError: Cannot read properties of undefined (reading
'clientModules')
### Why?
Since `default.tsx` is not a compulsory when you have slot that are
specific and ends with a dynamic route segment, this PR extends support
so that it is possible mixing catch-all routes with specific
non-catchall routes without requiring an additional `default.tsx` .
This PR will allow the following test cases to pass:
```
it('should not add the catch-all route to segments that have a more specific [dynamicRoute]', () => {
const appPaths = {
'/': ['/page'],
'/[[...catchAll]]': ['/[[...catchAll]]/page'],
'/nested/[foo]/[bar]/default': [
'/nested/[foo]/[bar]/default',
'/nested/[foo]/[bar]/@slot0/default',
'/nested/[foo]/[bar]/@slot2/default',
],
'/nested/[foo]/[bar]': [
'/nested/[foo]/[bar]/@slot0/page',
'/nested/[foo]/[bar]/@slot1/page',
],
'/nested/[foo]/[bar]/[baz]': [
'/nested/[foo]/[bar]/@slot0/[baz]/page',
'/nested/[foo]/[bar]/@slot1/[baz]/page',
],
'/[locale]/nested/[foo]/[bar]/[baz]/[qux]': [
'/[locale]/nested/[foo]/[bar]/@slot1/[baz]/[qux]/page',
],
}
const initialAppPaths = JSON.parse(JSON.stringify(appPaths))
normalizeCatchAllRoutes(appPaths)
expect(appPaths).toMatchObject(initialAppPaths)
})
...
```
```it('should not add the catch-all route to segments that have a more specific [dynamicRoute]', () => {
const appPaths = {
'/': ['/page'],
'/[[...catchAll]]': ['/[[...catchAll]]/page'],
'/nested/[foo]/[bar]/default': [
'/nested/[foo]/[bar]/default',
'/nested/[foo]/[bar]/@slot0/default',
'/nested/[foo]/[bar]/@slot2/default',
],
'/nested/[foo]/[bar]': [
'/nested/[foo]/[bar]/@slot0/page',
'/nested/[foo]/[bar]/@slot1/page',
],
'/nested/[foo]/[bar]/[baz]': [
'/nested/[foo]/[bar]/@slot0/[baz]/page',
'/nested/[foo]/[bar]/@slot1/[baz]/page',
],
'/[locale]/nested/[foo]/[bar]/[baz]/[qux]': [
'/[locale]/nested/[foo]/[bar]/@slot1/[baz]/[qux]/page',
],
}
...
```
and allow parallel routes defined in this [code
repro](https://github.com/williamli/nextjs-NEXT-2165) to build.
### How?
`packages/next/src/build/normalize-catchall-routes.ts` is extended to
check `appPath` to see if it is:
1. the route is not a catchall
2. `isMoreSpecific` than the closest `catchAllRoute`.
where `isMoreSpecific` is defined as:
```
function isMoreSpecific(pathname: string, catchAllRoute: string): boolean {
const pathnameDepth = pathname.split('/').length
const catchAllRouteDepth = catchAllRoute.split('/').length - 1
return pathnameDepth > catchAllRouteDepth
}
```
---------
Co-authored-by: Zack Tanner <zacktanner@gmail.com>
### 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
Willi#m ⬣
Zack Tanner