nextjs - ✅(Solved) Fix Prefetch full refetch the payload if there is already an inflight on Next 16 [1 pull requests, 1 participants]

hamidrezahanafi · 2025-11-22T00:58:27Z

[nextjs] PR 86700: fix: prevent duplicate RSC requests when navigation happens during inflight prefetch - Repository: vercel/next.js - Author: rosbitskyy - Sta… # PR #86700: fix: prevent duplicate RSC requests when navigation happens during inflight prefetch - Repository: vercel/next.js - Author: rosbitskyy - State: open | merged: False - Link: https://github.com/vercel/next.js/pull/86700 ## Description (problem / solution / changelog) ### What? Fixed duplicate RSC requests when navigation happens while a prefetch is already in progress. Previously, when a user clicked a link quickly after prefetch started, navigation would immediately make a new RSC request instead of waiting for the inflight prefetch to complete. ### Why? When a prefetch has `Pending` status (request already in flight), the navigation logic was only checking for `Fulfilled` status. If the prefetch was still pending, navigation would fall through to `navigateDynamicallyWithNoPrefetch`, which immediately makes a new RSC request. This caused duplicate requests and wasted network bandwidth, especially when users clicked links quickly after prefetch was initiated. ### How? - Added `promise` field to `PendingRouteCacheEntry` to track navigation requests waiting for prefetch completion - Created `waitForRouteCacheEntry` function (similar to `waitForSegmentCacheEntry`) that returns a promise resolving when the prefetch completes - Updated `fulfillRouteCacheEntry` and `rejectRouteCacheEntry` to resolve the promise when prefetch completes or fails - Modified `navigate` function to check for `Pending` status and wait for prefetch completion before making a new request - Added e2e test to verify only one request is made when navigation happens during inflight prefetch The implementation follows the same pattern already used for segment cache entries, ensuring consistency across the codebase. Fixes #86400 ## Changed files - `.gitignore` (modified, +1/-0) - `crates/next-core/src/next_shared/webpack_rules/sass.rs` (modified, +34/-2) - `packages/next/src/build/create-compiler-aliases.ts` (modified, +7/-2) - `packages/next/src/build/entries.ts` (modified, +0/-6) - `packages/next/src/client/components/app-router-announcer.tsx` (modified, +40/-15) - `packages/next/src/client/components/router-reducer/reducers/navigate-reducer.ts` (modified, +6/-1) - `packages/next/src/client/components/segment-cache/cache.ts` (modified, +41/-0) - `packages/next/src/client/components/segment-cache/navigation.ts` (modified, +97/-0) - `packages/next/src/client/web-vitals.ts` (modified, +104/-7) - `packages/next/src/server/app-render/create-component-styles-and-scripts.tsx` (modified, +1/-1) - `packages/next/src/server/app-render/dynamic-rendering.ts` (modified, +9/-0) - `packages/next/src/server/app-render/get-layer-assets.tsx` (modified, +1/-1) - `packages/next/src/server/base-server.ts` (modified, +16/-0) - `packages/next/src/server/config.ts` (modified, +3/-1) - `packages/next/src/server/lib/router-server.ts` (modified, +23/-0) - `packages/next/src/server/next-server.ts` (modified, +45/-7) - `packages/next/src/server/route-modules/app-route/module.ts` (modified, +91/-0) - `packages/next/src/server/route-modules/app-route/shared-modules.ts` (modified, +19/-1) - `packages/next/src/server/route-modules/route-module.ts` (modified, +1/-1) - `test/e2e/app-dir/app-middleware-proxy-esm/app-middleware-proxy-esm.test.ts` (added, +28/-0) - `test/e2e/app-dir/app-middleware-proxy-esm/app/api/test/route.js` (added, +5/-0) - `test/e2e/app-dir/app-middleware-proxy-esm/app/layout.js` (added, +7/-0) - `test/e2e/app-dir/app-middleware-proxy-esm/app/page.js` (added, +3/-0) - `test/e2e/app-dir/app-middleware-proxy-esm/app/rewritten/page.js` (added, +3/-0) - `test/e2e/app-dir/app-middleware-proxy-esm/next.config.js` (added, +6/-0) - `test/e2e/app-dir/app-middleware-proxy-esm/package.json` (added, +3/-0) - `test/e2e/app-dir/app-middleware-proxy-esm/proxy.js` (added, +24/-0) - `test/e2e/app-dir/app-routes/app-custom-routes.test.ts` (modified, +14/-0) - `test/e2e/app-dir/app-routes/app/layout.tsx` (modified, +2/-0) - `test/e2e/app-dir/app-routes/app/test-layout-cookies/layout.tsx` (added, +20/-0) - `test/e2e/app-dir/app-routes/app/test-layout-cookies/page.tsx` (added, +5/-0) - `test/e2e/app-dir/app/useReportWebVitals.test.ts` (modified, +52/-0) - `test/e2e/app-dir/cache-components-errors/cache-components-dynamic-metadata-empty-shell.test.ts` (added, +157/-0) - `test/e2e/app-dir/cache-components-errors/fixtures/dynamic-metadata-empty-shell/app/dynamic-metadata-connection-empty-shell/page.tsx` (added, +18/-0) - `test/e2e/app-dir/cache-components-errors/fixtures/dynamic-metadata-empty-shell/app/layout.tsx` (added, +11/-0) - `test/e2e/app-dir/cache-components-errors/fixtures/dynamic-metadata-empty-shell/next.config.js` (added, +9/-0) - `test/e2e/app-dir/cache-components/cache-components.test.ts` (modified, +24/-0) - `test/e2e/app-dir/interception-search-params-update/app/@modal/(.)search/page.tsx` (add

nextjs2025-11-22 00:58:27

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vercel/next.js#86400•Fetched 2026-04-08 02:11:10

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hamidrezahanafi

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Fix Action

Fixed

Fixed by PR: fix: prevent duplicate RSC requests when navigation happens during inflight prefetch (https://github.com/vercel/next.js/pull/86700)

PR fix notes

PR #86700: fix: prevent duplicate RSC requests when navigation happens during inflight prefetch

Repository: vercel/next.js
Author: rosbitskyy
State: open | merged: False
Link: https://github.com/vercel/next.js/pull/86700

Description (problem / solution / changelog)

What?

Fixed duplicate RSC requests when navigation happens while a prefetch is already in progress. Previously, when a user clicked a link quickly after prefetch started, navigation would immediately make a new RSC request instead of waiting for the inflight prefetch to complete.

Why?

When a prefetch has Pending status (request already in flight), the navigation logic was only checking for Fulfilled status. If the prefetch was still pending, navigation would fall through to navigateDynamicallyWithNoPrefetch, which immediately makes a new RSC request. This caused duplicate requests and wasted network bandwidth, especially when users clicked links quickly after prefetch was initiated.

How?

Added promise field to PendingRouteCacheEntry to track navigation requests waiting for prefetch completion
Created waitForRouteCacheEntry function (similar to waitForSegmentCacheEntry) that returns a promise resolving when the prefetch completes
Updated fulfillRouteCacheEntry and rejectRouteCacheEntry to resolve the promise when prefetch completes or fails
Modified navigate function to check for Pending status and wait for prefetch completion before making a new request
Added e2e test to verify only one request is made when navigation happens during inflight prefetch

The implementation follows the same pattern already used for segment cache entries, ensuring consistency across the codebase.

Fixes #86400

Changed files

.gitignore (modified, +1/-0)
crates/next-core/src/next_shared/webpack_rules/sass.rs (modified, +34/-2)
packages/next/src/build/create-compiler-aliases.ts (modified, +7/-2)
packages/next/src/build/entries.ts (modified, +0/-6)
packages/next/src/client/components/app-router-announcer.tsx (modified, +40/-15)
packages/next/src/client/components/router-reducer/reducers/navigate-reducer.ts (modified, +6/-1)
packages/next/src/client/components/segment-cache/cache.ts (modified, +41/-0)
packages/next/src/client/components/segment-cache/navigation.ts (modified, +97/-0)
packages/next/src/client/web-vitals.ts (modified, +104/-7)
packages/next/src/server/app-render/create-component-styles-and-scripts.tsx (modified, +1/-1)
packages/next/src/server/app-render/dynamic-rendering.ts (modified, +9/-0)
packages/next/src/server/app-render/get-layer-assets.tsx (modified, +1/-1)
packages/next/src/server/base-server.ts (modified, +16/-0)
packages/next/src/server/config.ts (modified, +3/-1)
packages/next/src/server/lib/router-server.ts (modified, +23/-0)
packages/next/src/server/next-server.ts (modified, +45/-7)
packages/next/src/server/route-modules/app-route/module.ts (modified, +91/-0)
packages/next/src/server/route-modules/app-route/shared-modules.ts (modified, +19/-1)
packages/next/src/server/route-modules/route-module.ts (modified, +1/-1)
test/e2e/app-dir/app-middleware-proxy-esm/app-middleware-proxy-esm.test.ts (added, +28/-0)
test/e2e/app-dir/app-middleware-proxy-esm/app/api/test/route.js (added, +5/-0)
test/e2e/app-dir/app-middleware-proxy-esm/app/layout.js (added, +7/-0)
test/e2e/app-dir/app-middleware-proxy-esm/app/page.js (added, +3/-0)
test/e2e/app-dir/app-middleware-proxy-esm/app/rewritten/page.js (added, +3/-0)
test/e2e/app-dir/app-middleware-proxy-esm/next.config.js (added, +6/-0)
test/e2e/app-dir/app-middleware-proxy-esm/package.json (added, +3/-0)
test/e2e/app-dir/app-middleware-proxy-esm/proxy.js (added, +24/-0)
test/e2e/app-dir/app-routes/app-custom-routes.test.ts (modified, +14/-0)
test/e2e/app-dir/app-routes/app/layout.tsx (modified, +2/-0)
test/e2e/app-dir/app-routes/app/test-layout-cookies/layout.tsx (added, +20/-0)
test/e2e/app-dir/app-routes/app/test-layout-cookies/page.tsx (added, +5/-0)
test/e2e/app-dir/app/useReportWebVitals.test.ts (modified, +52/-0)
test/e2e/app-dir/cache-components-errors/cache-components-dynamic-metadata-empty-shell.test.ts (added, +157/-0)
test/e2e/app-dir/cache-components-errors/fixtures/dynamic-metadata-empty-shell/app/dynamic-metadata-connection-empty-shell/page.tsx (added, +18/-0)
test/e2e/app-dir/cache-components-errors/fixtures/dynamic-metadata-empty-shell/app/layout.tsx (added, +11/-0)
test/e2e/app-dir/cache-components-errors/fixtures/dynamic-metadata-empty-shell/next.config.js (added, +9/-0)
test/e2e/app-dir/cache-components/cache-components.test.ts (modified, +24/-0)
test/e2e/app-dir/interception-search-params-update/app/@modal/(.)search/page.tsx (added, +13/-0)
test/e2e/app-dir/interception-search-params-update/app/@modal/default.tsx (added, +3/-0)
test/e2e/app-dir/interception-search-params-update/app/@modal/layout.tsx (added, +9/-0)
test/e2e/app-dir/interception-search-params-update/app/layout.tsx (added, +13/-0)
test/e2e/app-dir/interception-search-params-update/app/page.tsx (added, +11/-0)
test/e2e/app-dir/interception-search-params-update/app/search/page.tsx (added, +55/-0)
test/e2e/app-dir/interception-search-params-update/interception-search-params-update.test.ts (added, +77/-0)
test/e2e/app-dir/interception-search-params-update/next.config.js (added, +6/-0)
test/e2e/app-dir/segment-cache/prefetch-inflight-duplicate/app/layout.tsx (added, +11/-0)
test/e2e/app-dir/segment-cache/prefetch-inflight-duplicate/app/page.tsx (added, +12/-0)
test/e2e/app-dir/segment-cache/prefetch-inflight-duplicate/app/search/page.tsx (added, +8/-0)
test/e2e/app-dir/segment-cache/prefetch-inflight-duplicate/next.config.js (added, +5/-0)
test/e2e/app-dir/segment-cache/prefetch-inflight-duplicate/prefetch-inflight-duplicate.test.ts (added, +112/-0)
test/integration/next-image-new/loader-config-windows/dummy-loader.js (added, +3/-0)
test/integration/next-image-new/loader-config-windows/next.config.js (added, +8/-0)
test/integration/next-image-new/loader-config-windows/pages/get-img-props.js (added, +34/-0)
test/integration/next-image-new/loader-config-windows/pages/index.js (added, +35/-0)
test/integration/next-image-new/loader-config-windows/public/logo.png (added, +0/-0)
test/integration/next-image-new/loader-config-windows/test/index.test.ts (added, +89/-0)
test/production/app-dir/turbopack-bootstrap-scss-windows/app/globals.scss (added, +15/-0)
test/production/app-dir/turbopack-bootstrap-scss-windows/app/layout.tsx (added, +18/-0)
test/production/app-dir/turbopack-bootstrap-scss-windows/app/page.tsx (added, +12/-0)
test/production/app-dir/turbopack-bootstrap-scss-windows/index.test.ts (added, +43/-0)
test/production/app-dir/turbopack-bootstrap-scss-windows/next.config.js (added, +6/-0)
test/production/app-dir/turbopack-route-handler-notfound/app/api/not-found/route.ts (added, +5/-0)
test/production/app-dir/turbopack-route-handler-notfound/app/layout.tsx (added, +13/-0)
test/production/app-dir/turbopack-route-handler-notfound/app/page.tsx (added, +5/-0)
test/production/app-dir/turbopack-route-handler-notfound/index.test.ts (added, +33/-0)
test/unit/app-router-announcer.test.tsx (added, +319/-0)
test/unit/router-server-process-listeners.test.ts (added, +93/-0)
turbopack/crates/turbopack-ecmascript/src/minify.rs (modified, +6/-6)
turbopack/crates/turbopack-node/js/src/transforms/webpack-loaders.ts (modified, +7/-1)
turbopack/crates/turbopack-tests/tests/snapshot/basic/ecmascript_minify_inline_conflict/input/index.js (added, +25/-0)
turbopack/crates/turbopack-tests/tests/snapshot/basic/ecmascript_minify_inline_conflict/options.json (added, +9/-0)
turbopack/crates/turbopack-tests/tests/snapshot/basic/ecmascript_minify_inline_conflict/output/[turbopack]_runtime.js (added, +4/-0)
turbopack/crates/turbopack-tests/tests/snapshot/basic/ecmascript_minify_inline_conflict/output/[turbopack]_runtime.js.map (added, +5/-0)
turbopack/crates/turbopack-tests/tests/snapshot/basic/ecmascript_minify_inline_conflict/output/bf321_tests_snapshot_basic_ecmascript_minify_inline_conflict_input_index_3a45d1a2.js (added, +3/-0)
turbopack/crates/turbopack-tests/tests/snapshot/basic/ecmascript_minify_inline_conflict/output/bf321_tests_snapshot_basic_ecmascript_minify_inline_conflict_input_index_3a45d1a2.js.map (added, +1/-0)
turbopack/crates/turbopack-tests/tests/snapshot/basic/ecmascript_minify_inline_conflict/output/index.entry.js (added, +4/-0)
turbopack/crates/turbopack-tests/tests/snapshot/basic/ecmascript_minify_inline_conflict/output/index.entry.js.map (added, +5/-0)

Code Example

Operating System:
  Platform: darwin
  Arch: arm64
  Version: Darwin Kernel Version 24.6.0: Wed Oct 15 21:12:15 PDT 2025; root:xnu-11417.140.69.703.14~1/RELEASE_ARM64_T6041
  Available memory (MB): 49152
  Available CPU cores: 14
Binaries:
  Node: 22.20.0
  npm: 10.9.3
  Yarn: 1.22.22
  pnpm: N/A
Relevant Packages:
  next: 16.0.3 // Latest available version is detected (16.0.3).
  eslint-config-next: N/A
  react: 19.2.0
  react-dom: 19.2.0
  typescript: 5.9.3
Next.js Config:

RAW_BUFFERClick to expand / collapse

Link to the code that reproduces this issue

https://github.com/hamidrezahanafi/prefetch-full

To Reproduce

npm install
npm run build
npm run start
try to click on search link as fast as possible

Current vs. Expected behavior

Current Extra RSC request is being made even though a full prefetch is still on flight Expected Only one RSC request should go out even if the click is super fast

Provide environment information

Operating System:
  Platform: darwin
  Arch: arm64
  Version: Darwin Kernel Version 24.6.0: Wed Oct 15 21:12:15 PDT 2025; root:xnu-11417.140.69.703.14~1/RELEASE_ARM64_T6041
  Available memory (MB): 49152
  Available CPU cores: 14
Binaries:
  Node: 22.20.0
  npm: 10.9.3
  Yarn: 1.22.22
  pnpm: N/A
Relevant Packages:
  next: 16.0.3 // Latest available version is detected (16.0.3).
  eslint-config-next: N/A
  react: 19.2.0
  react-dom: 19.2.0
  typescript: 5.9.3
Next.js Config:

Which area(s) are affected? (Select all that apply)

Route Handlers

Which stage(s) are affected? (Select all that apply)

next start (local)

Additional context

No response

extent analysis

TL;DR

Implement a debouncing mechanism to prevent multiple RSC requests when clicking the search link rapidly.

Guidance

Review the prefetch implementation in the provided code to identify potential issues with concurrent requests.
Consider adding a flag to track whether a full prefetch is currently in flight and skip subsequent RSC requests until it completes.
Investigate using a library like lodash.debounce to simplify the debouncing logic.
Verify the fix by repeating the steps to reproduce the issue and checking the network requests.

Example

import debounce from 'lodash.debounce';

const isPrefetching = false;
const debouncedPrefetch = debounce(async () => {
  if (isPrefetching) return;
  isPrefetching = true;
  try {
    // Perform the prefetch request
  } finally {
    isPrefetching = false;
  }
}, 500); // Adjust the debounce timeout as needed

// Call debouncedPrefetch when the search link is clicked

Notes

The provided code and environment information suggest a Next.js application with a specific version of React and TypeScript.
The issue might be related to the implementation of prefetch in the next package or the application's custom routing logic.

Recommendation

Apply a workaround using debouncing to mitigate the issue, as the root cause may be related to the underlying library or framework.

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#memory management #API rate limit #retriever error #indexing error #inference speed

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nextjs - ✅(Solved) Fix Prefetch full refetch the payload if there is already an inflight on Next 16 [1 pull requests, 1 participants]

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Fix Action

Fixed

PR fix notes

PR #86700: fix: prevent duplicate RSC requests when navigation happens during inflight prefetch

Description (problem / solution / changelog)

What?

Why?

How?

Changed files

Code Example

Link to the code that reproduces this issue

To Reproduce

Current vs. Expected behavior

Provide environment information

Which area(s) are affected? (Select all that apply)

Which stage(s) are affected? (Select all that apply)

Additional context

extent analysis

TL;DR

Guidance

Example

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Recommendation

Still need to ship something?

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nextjs - ✅(Solved) Fix Prefetch full refetch the payload if there is already an inflight on Next 16 [1 pull requests, 1 participants]

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Fix Action

Fixed

PR fix notes

PR #86700: fix: prevent duplicate RSC requests when navigation happens during inflight prefetch

Description (problem / solution / changelog)

What?

Why?

How?

Changed files

Code Example

Link to the code that reproduces this issue

To Reproduce

Current vs. Expected behavior

Provide environment information

Which area(s) are affected? (Select all that apply)

Which stage(s) are affected? (Select all that apply)

Additional context

extent analysis

TL;DR

Guidance

Example

Notes

Recommendation

Still need to ship something?

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