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Segment Cache Silently Swallows RSC Navigation Failures And May Commit Stale Canonical URL

When the RSC payload fetch for client-side navigation hangs or rejects, the segment-cache navigation code catches the error and returns the current state, causing the click to be permanently lost with no fallback. Additionally, a cached route entry can supply a stale canonical URL containing query parameters from a previous render, leading to the address bar committing search params the user did not request.

highConfidence 88%Next.js Affected V16.2.6 Affected V16.3.2 Affected V16.4.0-Canary.4

Origin Analysis

In the segment-cache navigation logic, the promise from navigateToUnknownRoute is caught with a callback that returns the current state instead of performing a full-document fallback. This swallowed error prevents any retry or MPA navigation. The stale canonical URL issue arises because the cached Flight response includes a canonical URL that may contain query parameters from a prior render, and that cached URL is used verbatim when updating history, even if the target URL had no such search params.

1. Build a Next.js app with output: 'export' and serve the static export.\n2. Open a URL with search params (e.g., /projects?id=1&tab=estimate).\n3. Block or hang RSC payload fetches (e.g., patch window.fetch to return a pending promise for URLs containing '__next').\n4. Click a link to a different route (e.g., All Projects).\n5. Observe that nothing happens, no error is logged, and the URL remains unchanged.\n6. For the stale canonical URL symptom: with a cached route for /projects rendered with ?id=X&tab=Y, click a link to bare /projects from another page; note that the address bar changes to /projects?id=X&tab=Y.

Fixing Code Block

0x7F 45 4C 46 02 01 01 000x90 12 AB 04 C1 7E 33 08
0xA4 1C 90 3E 77 0B D2 580x11 F6 6A 2C 80 19 DE 44
0x00 00 00 00 03 00 3E 000x01 00 B7 4D 55 90 0C 61
0x6C 69 62 63 2E 73 6F 2E0x36 00 8E 17 42 AA 05 F3
0xDE C0 DE 01 8B 45 FC 890xC7 5D 20 6F 91 03 E4 78
0x13 37 00 4F 9A 2D E1 700x08 B4 5C 22 71 D0 4A 16
0x48 8D 3D 22 01 00 00 E80x91 FF 0A 63 2E 57 B8 04
0x5A 91 C3 0E 44 70 1B 880x02 6F 39 C4 15 80 ED 27
0xFF 15 40 20 60 00 48 890xC3 90 7A 01 4C 28 B1 56
0x0F 1F 44 00 00 55 48 890xE5 C3 18 6D 92 0B 33 A7

Edge Case Audit

The fallback to window.location.assign will cause a full page reload, which may be undesirable for purely client-side interactions and could lead to a double navigation if the original fetch eventually resolves. The sanitization of canonical URLs may break legitimate redirects or i18n routes that rely on server-provided canonical URLs differing from the requested href; test thoroughly with additional pathname features. This patch is a hotfix, not an official upstream solution; when upgrading Next.js, remove these overrides and verify that the underlying issue has been fixed to avoid conflicts with internal API changes. Rollback requires restoring the original catch block and canonical URL assignment.