Fix browser navigation buttons not working with shallow routing and middleware (#43919)

This PR fixes #41064.
In some particular cases, while using a middleware and shallow routing
the navigation get stucks and stop refreshing the page. After futher
investigation it seems that a line of code was added that causes the
router pathname to be incorrect and then making Next believe it's the
same page that is loading.

## Bug

- [x] Related issues linked using `fixes #number`
- [x] Integration tests added
- [x] 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)

Co-authored-by: JJ Kasper <jj@jjsweb.site>

packages/next/shared/lib/router/router.ts

@@ -1456,15 +1456,13 @@ export default class Router implements BaseRouter {
 
     // we don't attempt resolve asPath when we need to execute
     // middleware as the resolving will occur server-side
-    const isMiddlewareMatch = await matchesMiddleware({
-      asPath: as,
-      locale: nextState.locale,
-      router: this,
-    })
-
-    if (options.shallow && isMiddlewareMatch) {
-      pathname = this.pathname
-    }
+    const isMiddlewareMatch =
+      !options.shallow &&
+      (await matchesMiddleware({
+        asPath: as,
+        locale: nextState.locale,
+        router: this,
+      }))
 
     if (isQueryUpdating && isMiddlewareMatch) {
       shouldResolveHref = false

test/e2e/middleware-shallow-link/app/middleware.js

@@ -0,0 +1,9 @@
+import { NextResponse } from 'next/server'
+
+export async function middleware() {
+  return NextResponse.next()
+}
+
+export const config = {
+  matcher: '/(.*$)',
+}

test/e2e/middleware-shallow-link/app/pages/index.js

@@ -0,0 +1,26 @@
+import Link from 'next/link'
+import React from 'react'
+
+const Page = () => {
+  return (
+    <>
+      <h1>Content for page 1</h1>
+      <div>
+        <Link
+          data-next-shallow-push
+          shallow
+          href={{ query: { params: 'testParams' } }}
+        >
+          Shallow push
+        </Link>
+      </div>
+      <div>
+        <Link data-next-page href="/page2">
+          Go to page 2
+        </Link>
+      </div>
+    </>
+  )
+}
+
+export default Page

test/e2e/middleware-shallow-link/app/pages/page2.js

@@ -0,0 +1,25 @@
+import Link from 'next/link'
+import React from 'react'
+
+const Page = () => {
+  return (
+    <>
+      <h1>Content for page 2</h1>
+      <Link
+        data-next-shallow-replace
+        replace
+        shallow
+        href={{ query: { params: 'testParams' } }}
+      >
+        Shallow replace
+      </Link>
+      <div>
+        <button data-go-back onClick={() => window.history.back()}>
+          Go Back
+        </button>
+      </div>
+    </>
+  )
+}
+
+export default Page

test/e2e/middleware-shallow-link/index.test.ts

@@ -0,0 +1,42 @@
+import { createNext, FileRef } from 'e2e-utils'
+import { NextInstance } from 'test/lib/next-modes/base'
+import webdriver from 'next-webdriver'
+import { join } from 'path'
+
+describe('browser-shallow-navigation', () => {
+  let next: NextInstance
+
+  beforeAll(async () => {
+    next = await createNext({
+      files: {
+        pages: new FileRef(join(__dirname, 'app/pages')),
+        'middleware.js': new FileRef(join(__dirname, 'app/middleware.js')),
+      },
+    })
+  })
+
+  afterAll(() => next.destroy())
+
+  it('should render the correct page', async () => {
+    const browser = await webdriver(next.url, '/')
+
+    /// do shallow push
+    await browser.elementByCss('[data-next-shallow-push]').click()
+    await browser.waitForElementByCss('[data-next-page]')
+
+    // go to another page
+    await browser.elementByCss('[data-next-page]').click()
+    await browser.waitForElementByCss('[data-next-shallow-replace]')
+
+    // do shadow replace
+    await browser.elementByCss('[data-next-shallow-replace]').click()
+    await browser.waitForElementByCss('[data-go-back]')
+
+    // go back using history api
+    await browser.elementByCss('[data-go-back]').click()
+
+    // get page h1
+    let title = await browser.elementByCss('h1').text()
+    expect(title).toContain('Content for page 1')
+  })
+})