next.js

c7df8e99 - fix: trigger MPA navigation for server action redirects with build ID mismatch (#89946)

fix: trigger MPA navigation for server action redirects with build ID mismatch (#89946) ## Summary - Fixes cross-zone server action redirect failure where `redirect()` inside a server action produces a blank page when the target path is served by a different Next.js zone (separate Vercel project, same domain) - Adds build ID validation to `server-action-reducer.ts`, matching the existing pattern in `fetch-server-response.ts` - Adds e2e test in the deployment-skew test suite to verify server action redirects with build ID mismatch trigger MPA navigation ## Background When a server action calls `redirect()`, the server pre-fetches the redirect target and includes the RSC data in the response. In a multi-zone setup (same domain, different Next.js projects), this pre-fetched RSC data comes from a different build with a different build ID. The `fetch-server-response.ts` file already checks for build ID mismatches during regular navigations (line 245-251) and triggers MPA navigation when detected. However, `server-action-reducer.ts` was missing this check, causing the client to try to apply the foreign RSC payload — resulting in a blank page. ## Fix Added a build ID check in `fetchServerAction()` after parsing the RSC response. When a mismatch is detected, the flight data is discarded. The existing reducer logic at line 364-370 already handles this case: ```typescript if (flightData === undefined && redirectLocation !== undefined) { return completeHardNavigation(state, redirectLocation, navigateType) } ``` This triggers an MPA navigation (full page load), which is the correct behavior for cross-zone redirects. ## Repro - https://repro-main-app.vercel.app/test-redirect - Red button (server action redirect) → blank page (before fix) / full page load (after fix) - Green link (normal `<a>`) → works fine Closes https://linear.app/vercel/issue/NEXT-4856 --------- Co-authored-by: Zack Tanner <1939140+ztanner@users.noreply.github.com>