Provide non-dynamic segments to catch-all parallel routes (#65233)

Fixes an issue with https://github.com/vercel/next.js/pull/65063 where
the catch-all param only contains dynamic segments and is missing
non-dynamic route segments.

This makes building breadcrumbs extremely hard as we're missing
information to properly render the correct breadcrumb components.

This fix makes parallel route catch-all params behave like the standard
catch-all params in non-parallel routes

---------

Co-authored-by: Zack Tanner <1939140+ztanner@users.noreply.github.com>

packages/next/src/server/app-render/app-render.tsx

@@ -109,6 +109,7 @@ import {
 } from '../client-component-renderer-logger'
 import { createServerModuleMap } from './action-utils'
 import { isNodeNextRequest } from '../base-http/helpers'
+import { parseParameter } from '../../shared/lib/router/utils/route-regex'
 
 export type GetDynamicParamFromSegment = (
   // [slug] / [[slug]] / [...slug]
@@ -207,6 +208,7 @@ export type CreateSegmentPath = (child: FlightSegmentPath) => FlightSegmentPath
  */
 function makeGetDynamicParamFromSegment(
   params: { [key: string]: any },
+  pagePath: string,
   flightRouterState: FlightRouterState | undefined
 ): GetDynamicParamFromSegment {
   return function getDynamicParamFromSegment(
@@ -234,26 +236,46 @@ function makeGetDynamicParamFromSegment(
     }
 
     if (!value) {
-      // Handle case where optional catchall does not have a value, e.g. `/dashboard/[[...slug]]` when requesting `/dashboard`
-      if (
-        segmentParam.type === 'optional-catchall' ||
-        segmentParam.type === 'catchall'
-      ) {
-        // If we weren't able to match the segment to a URL param, and we have a catch-all route,
-        // provide all of the known params (in array format) to the route
-        // It should be safe to assume the order of these params is consistent with the order of the segments.
-        // However, if not, we could re-parse the `pagePath` with `getRouteRegex` and iterate over the positional order.
-        value = Object.values(params).map((i) => encodeURIComponent(i))
-        const hasValues = value.length > 0
-        const type = dynamicParamTypes[segmentParam.type]
+      const isCatchall = segmentParam.type === 'catchall'
+      const isOptionalCatchall = segmentParam.type === 'optional-catchall'
+
+      if (isCatchall || isOptionalCatchall) {
+        const dynamicParamType = dynamicParamTypes[segmentParam.type]
+        // handle the case where an optional catchall does not have a value,
+        // e.g. `/dashboard/[[...slug]]` when requesting `/dashboard`
+        if (isOptionalCatchall) {
+          return {
+            param: key,
+            value: null,
+            type: dynamicParamType,
+            treeSegment: [key, '', dynamicParamType],
+          }
+        }
+
+        // handle the case where a catchall or optional catchall does not have a value,
+        // e.g. `/foo/bar/hello` and `@slot/[...catchall]` or `@slot/[[...catchall]]` is matched
+        value = pagePath
+          .split('/')
+          // remove the first empty string
+          .slice(1)
+          // replace any dynamic params with the actual values
+          .map((pathSegment) => {
+            const param = parseParameter(pathSegment)
+
+            // if the segment matches a param, return the param value
+            // otherwise, it's a static segment, so just return that
+            return params[param.key] ?? param.key
+          })
+
         return {
           param: key,
-          value: hasValues ? value : null,
-          type: type,
+          value,
+          type: dynamicParamType,
           // This value always has to be a string.
-          treeSegment: [key, hasValues ? value.join('/') : '', type],
+          treeSegment: [key, value.join('/'), dynamicParamType],
         }
       }
+
       return findDynamicParamFromRouterState(flightRouterState, segment)
     }
 
@@ -795,6 +817,7 @@ async function renderToHTMLOrFlightImpl(
 
   const getDynamicParamFromSegment = makeGetDynamicParamFromSegment(
     params,
+    pagePath,
     // `FlightRouterState` is unconditionally provided here because this method uses it
     // to extract dynamic params as a fallback if they're not present in the path.
     parsedFlightRouterState

packages/next/src/shared/lib/router/utils/route-regex.ts

@@ -25,7 +25,7 @@ export interface RouteRegex {
  *   - `[foo]` -> `{ key: 'foo', repeat: false, optional: true }`
  *   - `bar` -> `{ key: 'bar', repeat: false, optional: false }`
  */
-function parseParameter(param: string) {
+export function parseParameter(param: string) {
   const optional = param.startsWith('[') && param.endsWith(']')
   if (optional) {
     param = param.slice(1, -1)

test/e2e/app-dir/parallel-routes-breadcrumbs/app/@slot/[...catchAll]/page.tsx

@@ -1,4 +1,4 @@
-export default function Page({ params: { catchAll } }) {
+export default function Page({ params: { catchAll = [] } }) {
   return (
     <div id="slot">
       <h1>Parallel Route!</h1>

test/e2e/app-dir/parallel-routes-breadcrumbs/app/foo/[lang]/bar/page.tsx

@@ -0,0 +1,7 @@
+export default function StaticPage() {
+  return (
+    <div>
+      <h2>/foo/[lang]/bar Page!</h2>
+    </div>
+  )
+}

test/e2e/app-dir/parallel-routes-breadcrumbs/parallel-routes-breadcrumbs.test.ts

@@ -44,4 +44,19 @@ describe('parallel-routes-breadcrumbs', () => {
     expect(await slot.text()).toContain('Album: album2')
     expect(await slot.text()).toContain('Track: track3')
   })
+
+  it('should render the breadcrumbs correctly with the non-dynamic route segments', async () => {
+    const browser = await next.browser('/foo/en/bar')
+    const slot = await browser.waitForElementByCss('#slot')
+
+    expect(await browser.elementByCss('h1').text()).toBe('Parallel Route!')
+    expect(await browser.elementByCss('h2').text()).toBe(
+      '/foo/[lang]/bar Page!'
+    )
+
+    // verify slot is rendering the params
+    expect(await slot.text()).toContain('Artist: foo')
+    expect(await slot.text()).toContain('Album: en')
+    expect(await slot.text()).toContain('Track: bar')
+  })
 })