Cached Navigations: Cache static stage of partially static initial HTML by unstubbable · Pull Request #90539 · vercel/next.js

unstubbable · 2026-02-25T20:33:16Z

When a partially static page is loaded via initial HTML (PPR resume), the RSC payload now includes the l (static stage byte length) field, enabling the client router to extract and cache the static stage during hydration. Subsequent navigations to the same page serve the cached static content instantly while streaming in dynamic content.

On the server, the resume path in renderToStream now uses staged rendering (mirroring generateStagedDynamicFlightRenderResult) when Cache Components is enabled. A StagedRenderingController separates the static and dynamic stages, and countStaticStageBytes resolves the byte length promise that Flight serializes into the stream as l. getRSCPayload accepts staleTimeIterable and staticStageByteLengthPromise options to wire s and l into the InitialRSCPayload.

On the client, app-index.tsx tees the inlined Flight stream when Cache Components is enabled. One copy goes to React for decoding, the other is passed to createInitialRouterState. When l is present (partially static), the clone is truncated at the byte boundary via decodeStaticStage and written into the segment cache via writeStaticStageResponseIntoCache with isResponsePartial: true. When l is absent but s is present (fully static), the same function is used with isResponsePartial: false.

createInitialRouterState now accepts a single initialRSCPayload: InitialRSCPayload prop instead of individual destructured fields.

unstubbable · 2026-02-25T20:33:31Z

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nextjs-bot · 2026-02-25T21:12:15Z

Tests Passed

nextjs-bot · 2026-02-26T12:00:59Z

Stats from current PR

🔴 2 regressions

Metric	Canary	PR	Change	Trend
node_modules Size	475 MB	476 MB	🔴 +163 kB (+0%)	▁▁▁▁▁
Cold (Listen)	1.014s	1.117s	🔴 +103ms (+10%)	▇█▁▂▁

📊 All Metrics

📖 Metrics Glossary

Dev Server Metrics:

Listen = TCP port starts accepting connections
First Request = HTTP server returns successful response
Cold = Fresh build (no cache)
Warm = With cached build artifacts

Build Metrics:

Fresh = Clean build (no .next directory)
Cached = With existing .next directory

Change Thresholds:

Time: Changes < 50ms AND < 10%, OR < 2% are insignificant
Size: Changes < 1KB AND < 1% are insignificant
All other changes are flagged to catch regressions

⚡ Dev Server

Metric	Canary	PR	Change	Trend
Cold (Listen)	1.014s	1.117s	🔴 +103ms (+10%)	▇█▁▂▁
Cold (Ready in log)	1.008s	1.088s	✓	▇█▁▂▁
Cold (First Request)	1.836s	1.922s	✓	▇█▃▂▃
Warm (Listen)	1.013s	1.066s	✓	▇█▁▂▁
Warm (Ready in log)	1.018s	1.049s	✓	▇█▁▂▁
Warm (First Request)	772ms	810ms	✓	▇█▁▁▂

📦 Dev Server (Webpack) (Legacy)

📦 Dev Server (Webpack)

Metric	Canary	PR	Change	Trend
Cold (Listen)	455ms	456ms	✓	▁▁▁▁▁
Cold (Ready in log)	437ms	437ms	✓	▁▆▆▅▅
Cold (First Request)	1.931s	1.954s	✓	▁▃▄▂▂
Warm (Listen)	456ms	456ms	✓	▁▁▁▁▁
Warm (Ready in log)	436ms	437ms	✓	▁▅▅▆▅
Warm (First Request)	1.955s	1.941s	✓	▁▃▄▃▃

⚡ Production Builds

Metric	Canary	PR	Change	Trend
Fresh Build	7.752s	7.984s	✓	▆█▁▃▁
Cached Build	7.478s	7.659s	✓	▆█▁▃▁

📦 Production Builds (Webpack) (Legacy)

📦 Production Builds (Webpack)

Metric	Canary	PR	Change	Trend
Fresh Build	14.022s	14.006s	✓	▁▁▄▁▁
Cached Build	14.088s	14.105s	✓	▁▁▄▁▁
node_modules Size	475 MB	476 MB	🔴 +163 kB (+0%)	▁▁▁▁▁

📦 Bundle Sizes

Bundle Sizes

⚡ Turbopack

Client

Main Bundles: **401 kB** → **401 kB** ⚠️ +26 B

80 files with content-based hashes (individual files not comparable between builds)

Server

Middleware

	Canary	PR	Change
middleware-b..fest.js gzip	771 B	766 B	✓
Total	771 B	766 B	✅ -5 B

Build Details

Build Manifests

	Canary	PR	Change
_buildManifest.js gzip	450 B	452 B	✓
Total	450 B	452 B	⚠️ +2 B

📦 Webpack

Client

Main Bundles

	Canary	PR	Change
5528-HASH.js gzip	5.54 kB	N/A	-
6280-HASH.js gzip	59 kB	N/A	-
6335.HASH.js gzip	169 B	N/A	-
912-HASH.js gzip	4.59 kB	N/A	-
e8aec2e4-HASH.js gzip	62.6 kB	N/A	-
framework-HASH.js gzip	59.7 kB	59.7 kB	✓
main-app-HASH.js gzip	256 B	254 B	✓
main-HASH.js gzip	39.1 kB	39.1 kB	✓
webpack-HASH.js gzip	1.68 kB	1.68 kB	✓
262-HASH.js gzip	N/A	4.59 kB	-
2889.HASH.js gzip	N/A	169 B	-
5602-HASH.js gzip	N/A	5.55 kB	-
6948ada0-HASH.js gzip	N/A	62.6 kB	-
9544-HASH.js gzip	N/A	59.8 kB	-
Total	233 kB	234 kB	⚠️ +784 B

Polyfills

	Canary	PR	Change
polyfills-HASH.js gzip	39.4 kB	39.4 kB	✓
Total	39.4 kB	39.4 kB	✓

Pages

	Canary	PR	Change
_app-HASH.js gzip	194 B	194 B	✓
_error-HASH.js gzip	183 B	180 B	🟢 3 B (-2%)
css-HASH.js gzip	331 B	330 B	✓
dynamic-HASH.js gzip	1.81 kB	1.81 kB	✓
edge-ssr-HASH.js gzip	256 B	256 B	✓
head-HASH.js gzip	351 B	352 B	✓
hooks-HASH.js gzip	384 B	383 B	✓
image-HASH.js gzip	580 B	581 B	✓
index-HASH.js gzip	260 B	260 B	✓
link-HASH.js gzip	2.51 kB	2.51 kB	✓
routerDirect..HASH.js gzip	320 B	319 B	✓
script-HASH.js gzip	386 B	386 B	✓
withRouter-HASH.js gzip	315 B	315 B	✓
1afbb74e6ecf..834.css gzip	106 B	106 B	✓
Total	7.98 kB	7.98 kB	✅ -1 B

Server

Edge SSR

	Canary	PR	Change
edge-ssr.js gzip	125 kB	125 kB	✓
page.js gzip	254 kB	256 kB	✓
Total	379 kB	380 kB	⚠️ +1.21 kB

Middleware

	Canary	PR	Change
middleware-b..fest.js gzip	617 B	617 B	✓
middleware-r..fest.js gzip	156 B	155 B	✓
middleware.js gzip	43.5 kB	43.9 kB	✓
edge-runtime..pack.js gzip	842 B	842 B	✓
Total	45.2 kB	45.5 kB	⚠️ +320 B

Build Details

Build Manifests

	Canary	PR	Change
_buildManifest.js gzip	715 B	718 B	✓
Total	715 B	718 B	⚠️ +3 B

Build Cache

	Canary	PR	Change
0.pack gzip	4.05 MB	4.06 MB	🔴 +6.84 kB (+0%)
index.pack gzip	103 kB	103 kB	✓
index.pack.old gzip	104 kB	103 kB	✓
Total	4.26 MB	4.26 MB	⚠️ +6.78 kB

🔄 Shared (bundler-independent)

Runtimes

	Canary	PR	Change
app-page-exp...dev.js gzip	321 kB	321 kB	✓
app-page-exp..prod.js gzip	170 kB	170 kB	✓
app-page-tur...dev.js gzip	321 kB	321 kB	✓
app-page-tur..prod.js gzip	170 kB	170 kB	✓
app-page-tur...dev.js gzip	317 kB	318 kB	✓
app-page-tur..prod.js gzip	168 kB	168 kB	✓
app-page.run...dev.js gzip	318 kB	318 kB	✓
app-page.run..prod.js gzip	168 kB	169 kB	✓
app-route-ex...dev.js gzip	70.8 kB	70.8 kB	✓
app-route-ex..prod.js gzip	49.3 kB	49.3 kB	✓
app-route-tu...dev.js gzip	70.9 kB	70.9 kB	✓
app-route-tu..prod.js gzip	49.3 kB	49.3 kB	✓
app-route-tu...dev.js gzip	70.5 kB	70.5 kB	✓
app-route-tu..prod.js gzip	49 kB	49 kB	✓
app-route.ru...dev.js gzip	70.4 kB	70.4 kB	✓
app-route.ru..prod.js gzip	49 kB	49 kB	✓
dist_client_...dev.js gzip	324 B	324 B	✓
dist_client_...dev.js gzip	326 B	326 B	✓
dist_client_...dev.js gzip	318 B	318 B	✓
dist_client_...dev.js gzip	317 B	317 B	✓
pages-api-tu...dev.js gzip	43.2 kB	43.2 kB	✓
pages-api-tu..prod.js gzip	32.9 kB	32.9 kB	✓
pages-api.ru...dev.js gzip	43.2 kB	43.2 kB	✓
pages-api.ru..prod.js gzip	32.9 kB	32.9 kB	✓
pages-turbo....dev.js gzip	52.6 kB	52.6 kB	✓
pages-turbo...prod.js gzip	38.5 kB	38.5 kB	✓
pages.runtim...dev.js gzip	52.6 kB	52.6 kB	✓
pages.runtim..prod.js gzip	38.5 kB	38.5 kB	✓
server.runti..prod.js gzip	61.9 kB	61.9 kB	✓
Total	2.83 MB	2.83 MB	⚠️ +1.89 kB

📝 Changed Files (8 files)

Files with changes:

app-page-exp..ntime.dev.js
app-page-exp..time.prod.js
app-page-tur..ntime.dev.js
app-page-tur..time.prod.js
app-page-tur..ntime.dev.js
app-page-tur..time.prod.js
app-page.runtime.dev.js
app-page.runtime.prod.js

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app-page-exp..time.prod.js

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app-page-tur..ntime.dev.js

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app-page-tur..time.prod.js

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app-page-tur..ntime.dev.js

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app-page-tur..time.prod.js

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app-page.runtime.dev.js

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app-page.runtime.prod.js

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📎 Tarball URL

https://vercel-packages.vercel.app/next/commits/77ae56e3cf6ffa38a24eace9a471c684b7184603/next

When a partially static page is loaded via initial HTML (PPR resume), the RSC payload now includes the `l` (static stage byte length) field, enabling the client to extract and cache the static stage during hydration. Subsequent navigations to the same page serve the cached static content instantly while streaming in dynamic content. On the server, the resume path in `renderToStream` now uses staged rendering (mirroring `generateStagedDynamicFlightRenderResult`) when Cache Components is enabled. A `StagedRenderingController` separates the static and dynamic stages, and `countStaticStageBytes` resolves the byte length promise that Flight serializes into the stream as `l`. `getRSCPayload` accepts `staleTimeIterable` and `staticStageByteLengthPromise` options to wire `s` and `l` into the `InitialRSCPayload`. On the client, `app-index.tsx` tees the inlined Flight stream when Cache Components is enabled. One copy goes to React for decoding, the other is passed to `createInitialRouterState`. When `l` is present (partially static), the clone is truncated at the byte boundary via the new `decodeStaticStage` helper and written into the segment cache via `processStaticStageResponse` and `writeStaticStageResponseIntoCache`. When `l` is absent but `s` is present (fully static), the existing `writeInitialSeedDataIntoCache` path is used unchanged. `createInitialRouterState` now accepts a single `initialRSCPayload: InitialRSCPayload` prop instead of individual destructured fields. `resolveStaticStageData`, `processStaticStageResponse`, `writeStaticStageResponseIntoCache`, and `writeDynamicRenderResponseIntoCache` are widened to accept `NavigationFlightResponse | InitialRSCPayload`.

…ML (#90539) When a partially static page is loaded via initial HTML (PPR resume), the RSC payload now includes the `l` (static stage byte length) field, enabling the client router to extract and cache the static stage during hydration. Subsequent navigations to the same page serve the cached static content instantly while streaming in dynamic content. On the server, the resume path in `renderToStream` now uses staged rendering (mirroring `generateStagedDynamicFlightRenderResult`) when Cache Components is enabled. A `StagedRenderingController` separates the static and dynamic stages, and `countStaticStageBytes` resolves the byte length promise that Flight serializes into the stream as `l`. `getRSCPayload` accepts `staleTimeIterable` and `staticStageByteLengthPromise` options to wire `s` and `l` into the `InitialRSCPayload`. On the client, `app-index.tsx` tees the inlined Flight stream when Cache Components is enabled. One copy goes to React for decoding, the other is passed to `createInitialRouterState`. When `l` is present (partially static), the clone is truncated at the byte boundary via `decodeStaticStage` and written into the segment cache via `writeStaticStageResponseIntoCache` with `isResponsePartial: true`. When `l` is absent but `s` is present (fully static), the same function is used with `isResponsePartial: false`. `createInitialRouterState` now accepts a single `initialRSCPayload: InitialRSCPayload` prop instead of individual destructured fields.

unstubbable mentioned this pull request Feb 25, 2026

Cached Navigations: Serve cached segments instantly on repeat visits #90223

Merged

nextjs-bot added created-by: Next.js team PRs by the Next.js team. tests type: next labels Feb 25, 2026

This was referenced Feb 25, 2026

Fix runtime prefetch isPartial byte stripping when deployed #90272

Merged

Cached Navigations: Cache visited fully static pages in the segment cache #90306

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unstubbable force-pushed the hl/cached-navs-2 branch 2 times, most recently from 59984fa to c0d147a Compare February 25, 2026 21:45

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unstubbable marked this pull request as ready for review February 26, 2026 16:19

unstubbable requested a review from acdlite February 26, 2026 16:19

unstubbable force-pushed the hl/cached-navs-3 branch from 2898e04 to ef7164a Compare February 27, 2026 10:12

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unstubbable mentioned this pull request Feb 27, 2026

Cached Navigations: Cache runtime stage data from navigation requests #90666

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Base automatically changed from hl/cached-navs-2 to canary March 4, 2026 15:20

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unstubbable merged commit 5a18a71 into canary Mar 4, 2026
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Cached Navigations: Cache static stage of partially static initial HTML#90539

Cached Navigations: Cache static stage of partially static initial HTML#90539
unstubbable merged 1 commit intocanaryfrom
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