Add missing isRootLayout when creating optimistic tree (vercel#45899)

Fixes vercel#45750
Closes vercel#45822 
Fixes NEXT-514

Ensures rootlayout marker is copied into the optimistic tree.

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## Bug

- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Errors have a helpful link attached, see
[`contributing.md`](https://github.com/vercel/next.js/blob/canary/contributing.md)

## Feature

- [ ] Implements an existing feature request or RFC. Make sure the
feature request has been accepted for implementation before opening a
PR.
- [ ] Related issues linked using `fixes #number`
- [ ]
[e2e](https://github.com/vercel/next.js/blob/canary/contributing/core/testing.md#writing-tests-for-nextjs)
tests added
- [ ] Documentation added
- [ ] Telemetry added. In case of a feature if it's used or not.
- [ ] Errors have a helpful link attached, see
[`contributing.md`](https://github.com/vercel/next.js/blob/canary/contributing.md)

## Documentation / Examples

- [ ] Make sure the linting passes by running `pnpm build && pnpm lint`
- [ ] The "examples guidelines" are followed from [our contributing
doc](https://github.com/vercel/next.js/blob/canary/contributing/examples/adding-examples.md)

Author: timneutkens

packages/next/src/client/components/router-reducer/create-optimistic-tree.test.ts

@@ -42,6 +42,9 @@ describe('createOptimisticTree', () => {
           'refetch',
         ],
       },
+      undefined,
+      undefined,
+      true,
     ])
   })
 })

packages/next/src/client/components/router-reducer/create-optimistic-tree.ts

@@ -10,10 +10,8 @@ export function createOptimisticTree(
   flightRouterState: FlightRouterState | null,
   parentRefetch: boolean
 ): FlightRouterState {
-  const [existingSegment, existingParallelRoutes] = flightRouterState || [
-    null,
-    {},
-  ]
+  const [existingSegment, existingParallelRoutes, url, refresh, isRootLayout] =
+    flightRouterState || [null, {}]
   const segment = segments[0]
   const isLastSegment = segments.length === 1
 
@@ -45,8 +43,18 @@ export function createOptimisticTree(
     },
   ]
 
+  if (url) {
+    result[2] = url
+  }
+
   if (!parentRefetch && shouldRefetchThisLevel) {
     result[3] = 'refetch'
+  } else if (segmentMatches && refresh) {
+    result[3] = refresh
+  }
+
+  if (segmentMatches && isRootLayout) {
+    result[4] = isRootLayout
   }
 
   return result

test/e2e/app-dir/app-prefetch/app/prefetch-false/initial/page.js

@@ -0,0 +1,15 @@
+import Link from 'next/link'
+
+export default function Page() {
+  return (
+    <>
+      <Link
+        href="/prefetch-false/result"
+        prefetch={false}
+        id="to-prefetch-false-result"
+      >
+        To prefetch false
+      </Link>
+    </>
+  )
+}

test/e2e/app-dir/app-prefetch/app/prefetch-false/result/page.js

@@ -0,0 +1,3 @@
+export default function Page() {
+  return <h1 id="prefetch-false-page-result">Result page</h1>
+}

test/e2e/app-dir/app-prefetch/prefetching.test.ts

@@ -98,5 +98,17 @@ createNextDescribe(
         ).toBe(0)
       }
     })
+
+    it('should navigate when prefetch is false', async () => {
+      const browser = await next.browser('/prefetch-false/initial')
+      await browser
+        .elementByCss('#to-prefetch-false-result')
+        .click()
+        .waitForElementByCss('#prefetch-false-page-result')
+
+      expect(
+        await browser.elementByCss('#prefetch-false-page-result').text()
+      ).toBe('Result page')
+    })
   }
 )