Include HMR refresh hash in "use cache" cache keys

[unstubbable]

Today, when editing server components that use "use cache" functions, only updates to the uncached parts of the component will be reflected in the rendered result after the HMR refresh was applied. Any cached functions/components will show the same content as before the edit.

This is problematic when a function with a "use cache" directive is edited. In this case, the edits won't be applied, and stale content is shown in the browser, until the dev server is restarted.

With this PR, we are now including an HMR refresh hash in the cache key for all "use cache" functions. This ensures that those functions are revalidated when a server component is edited, which avoids showing stale content.

However, while the "use cache" functions are revalidated during the HMR refresh, we will still restore any fetches inside of "use cache" from the server components HMR cache (unless their input changed because of the edit).

For Webpack, a real content hash is used, which means that if an edit is reverted to a prior edit, the previously cached data will be retrieved from the cache. For Turbopack, the HMR hash is currently just an incrementing counter, which may be improved in a follow-up PR.

closes NAR-65

[ijjk]

Stats from current PR

Default Build (Increase detected ⚠️)

General Overall increase ⚠️

	vercel/next.js canary	vercel/next.js hl/use-cache-fix-hmr	Change
buildDuration	19.6s	17.8s	N/A
buildDurationCached	17.1s	14.2s	N/A
nodeModulesSize	391 MB	391 MB	⚠️ +28.1 kB
nextStartRea..uration (ms)	459ms	464ms	N/A

Client Bundles (main, webpack)

	vercel/next.js canary	vercel/next.js hl/use-cache-fix-hmr	Change
5306-HASH.js gzip	54 kB	54 kB	N/A
8276.HASH.js gzip	169 B	168 B	N/A
8377-HASH.js gzip	5.46 kB	5.46 kB	N/A
bccd1874-HASH.js gzip	52.9 kB	52.9 kB	N/A
framework-HASH.js gzip	57.5 kB	57.5 kB	N/A
main-app-HASH.js gzip	241 B	242 B	N/A
main-HASH.js gzip	34.5 kB	34.4 kB	N/A
webpack-HASH.js gzip	1.71 kB	1.71 kB	N/A
Overall change	0 B	0 B	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	vercel/next.js hl/use-cache-fix-hmr	Change
polyfills-HASH.js gzip	39.4 kB	39.4 kB	✓
Overall change	39.4 kB	39.4 kB	✓

Client Pages

	vercel/next.js canary	vercel/next.js hl/use-cache-fix-hmr	Change
_app-HASH.js gzip	193 B	193 B	✓
_error-HASH.js gzip	193 B	193 B	✓
amp-HASH.js gzip	512 B	510 B	N/A
css-HASH.js gzip	343 B	342 B	N/A
dynamic-HASH.js gzip	1.84 kB	1.84 kB	✓
edge-ssr-HASH.js gzip	265 B	265 B	✓
head-HASH.js gzip	363 B	362 B	N/A
hooks-HASH.js gzip	393 B	392 B	N/A
image-HASH.js gzip	4.59 kB	4.58 kB	N/A
index-HASH.js gzip	268 B	268 B	✓
link-HASH.js gzip	2.35 kB	2.35 kB	N/A
routerDirect..HASH.js gzip	328 B	328 B	✓
script-HASH.js gzip	397 B	397 B	✓
withRouter-HASH.js gzip	323 B	326 B	N/A
1afbb74e6ecf..834.css gzip	106 B	106 B	✓
Overall change	3.59 kB	3.59 kB	✓

Client Build Manifests

	vercel/next.js canary	vercel/next.js hl/use-cache-fix-hmr	Change
_buildManifest.js gzip	748 B	747 B	N/A
Overall change	0 B	0 B	✓

Rendered Page Sizes

	vercel/next.js canary	vercel/next.js hl/use-cache-fix-hmr	Change
index.html gzip	523 B	524 B	N/A
link.html gzip	538 B	538 B	✓
withRouter.html gzip	519 B	520 B	N/A
Overall change	538 B	538 B	✓

Edge SSR bundle Size

	vercel/next.js canary	vercel/next.js hl/use-cache-fix-hmr	Change
edge-ssr.js gzip	129 kB	129 kB	N/A
page.js gzip	210 kB	210 kB	N/A
Overall change	0 B	0 B	✓

Middleware size

	vercel/next.js canary	vercel/next.js hl/use-cache-fix-hmr	Change
middleware-b..fest.js gzip	670 B	665 B	N/A
middleware-r..fest.js gzip	155 B	156 B	N/A
middleware.js gzip	31.3 kB	31.3 kB	N/A
edge-runtime..pack.js gzip	844 B	844 B	✓
Overall change	844 B	844 B	✓

Next Runtimes

	vercel/next.js canary	vercel/next.js hl/use-cache-fix-hmr	Change
app-page-exp...dev.js gzip	385 kB	385 kB	N/A
app-page-exp..prod.js gzip	132 kB	132 kB	✓
app-page-tur..prod.js gzip	145 kB	145 kB	✓
app-page-tur..prod.js gzip	141 kB	141 kB	✓
app-page.run...dev.js gzip	372 kB	372 kB	N/A
app-page.run..prod.js gzip	128 kB	128 kB	✓
app-route-ex...dev.js gzip	39.2 kB	39.3 kB	N/A
app-route-ex..prod.js gzip	25.6 kB	25.6 kB	N/A
app-route-tu..prod.js gzip	25.6 kB	25.6 kB	N/A
app-route-tu..prod.js gzip	25.4 kB	25.4 kB	N/A
app-route.ru...dev.js gzip	40.8 kB	40.8 kB	N/A
app-route.ru..prod.js gzip	25.4 kB	25.4 kB	N/A
dist_client_...dev.js gzip	356 B	356 B	✓
dist_client_...dev.js gzip	349 B	349 B	✓
pages-api-tu..prod.js gzip	9.69 kB	9.69 kB	✓
pages-api.ru...dev.js gzip	11.8 kB	11.8 kB	✓
pages-api.ru..prod.js gzip	9.68 kB	9.68 kB	✓
pages-turbo...prod.js gzip	21.9 kB	21.9 kB	✓
pages.runtim...dev.js gzip	31.5 kB	31.5 kB	✓
pages.runtim..prod.js gzip	21.9 kB	21.9 kB	✓
server.runti..prod.js gzip	60.2 kB	60.2 kB	✓
Overall change	713 kB	713 kB	✓

build cache Overall increase ⚠️

	vercel/next.js canary	vercel/next.js hl/use-cache-fix-hmr	Change
0.pack gzip	2.1 MB	2.1 MB	⚠️ +4.8 kB
index.pack gzip	76.7 kB	74.8 kB	N/A
Overall change	2.1 MB	2.1 MB	⚠️ +4.8 kB

Diff details

Diff for middleware.js

Diff too large to display

Diff for edge-ssr.js

Diff too large to display

Diff for 5306-HASH.js

Diff too large to display

Diff for main-HASH.js

Diff too large to display

Diff for app-page-exp..ntime.dev.js

Diff too large to display

Diff for app-page.runtime.dev.js

Diff too large to display

Diff for app-route-ex..ntime.dev.js

Diff too large to display

Diff for app-route-ex..time.prod.js

Diff too large to display

Diff for app-route-tu..time.prod.js

Diff too large to display

Diff for app-route-tu..time.prod.js

Diff too large to display

Diff for app-route.runtime.dev.js

Diff too large to display

Diff for app-route.ru..time.prod.js

Diff too large to display

Commit: 0cc4fc5

[unstubbable]

• Add regression test for previously hanging compilation with Turbopack #75507
• Include HMR refresh hash in "use cache" cache keys #75474 👈 (View in Graphite)
• canary

This stack of pull requests is managed by Graphite. Learn more about stacking.