next.js

0a2bdd7f - Handle null history.state in client-side router popstate handler (#90083)

Handle null history.state in client-side router popstate handler (#90083) ### What? Handle `null` `history.state` in the client-side router's `popstate` handler. ### Why? When `pushState` or `replaceState` is called outside of Next.js with a `null` state (or the initial history entry has no state), navigating back/forward to that entry fires a `popstate` event with `event.state === null`. Previously, the `onPopState` handler returned early without doing anything, leaving the router tree completely out of sync with the browser URL — `usePathname()`, `useSearchParams()`, etc. would return stale values. ### How? When `event.state` is `null`, call `window.location.reload()` to perform a hard navigation, the same behavior as when a non-Next.js history entry is encountered (`!event.state.__NA`). This ensures the router always returns to a consistent state. Added an e2e test that: 1. Navigates to a second page via client-side Link 2. Pushes history entries with truly `null` state (via `History.prototype.pushState` to bypass the Next.js patch) 3. Goes back and verifies the page correctly reloads Fixes #90080