fix(instrumentation): load segmentData from disk in registerInitialCache - #237
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AyronK merged 1 commit intoAug 12, 2026
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In Next.js 16.3.0 the segment prefetch protocol changed: the browser sends `next-router-segment-prefetch: /_tree` requests expecting a compact TreePrefetch payload. When segmentData is missing from the cached ISR entry the server falls back to returning the full-page RSC (InitialRSCPayload), which the Next.js 16 client cannot parse as a route-tree response and retries indefinitely — causing a flood of RSC fetch calls for the entire cache TTL after every deploy. Each pre-rendered App Router page now ships alongside a `<route>.segments/` directory whose files contain the per-segment RSC payloads (/_tree, /_full, /$locale, …). The route's .meta file lists them in a `segmentPaths` array. This commit: - Adds `segmentPaths?: string[]` to the `NextRouteMetadata` type so the field is recognised when the .meta file is parsed. - After reading the .meta file, reads every segment file listed in `meta.segmentPaths` from the `.segments/` directory and builds a `Map<string, Buffer>` that is stored as `segmentData` on the cached value. Files that are absent are skipped silently so the function remains backwards-compatible with Next.js 15 builds (which produce no .segments directories).
AyronK
self-requested a review
August 12, 2026 10:11
AyronK
approved these changes
Aug 12, 2026
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Thanks @gergokee, I'll draft a patch today. |
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In Next.js 16.3.0 the segment prefetch protocol changed: the browser sends
next-router-segment-prefetch: /_treerequests expecting a compact TreePrefetch payload. When segmentData is missing from the cached ISR entry the server falls back to returning the full-page RSC (InitialRSCPayload), which the Next.js 16 client cannot parse as a route-tree response and retries indefinitely — causing a flood of RSC fetch calls for the entire cache TTL after every deploy.Each pre-rendered App Router page now ships alongside a
<route>.segments/directory whose files contain the per-segment RSC payloads (/_tree, /_full, /$locale, …). The route's .meta file lists them in asegmentPathsarray.This commit:
segmentPaths?: string[]to theNextRouteMetadatatype so the field is recognised when the .meta file is parsed.meta.segmentPathsfrom the.segments/directory and builds aMap<string, Buffer>that is stored assegmentDataon the cached value. Files that are absent are skipped silently so the function remains backwards-compatible with Next.js 15 builds (which produce no .segments directories).