Freeze loaded manifests

[wyattjoh]

Manifests in the runtime should be treated as immutable objects to ensure that side effects aren't created that depend on the mutability of these shared objects. Instead, mutable references should be used in places where this is desirable.

This also introduces the new DeepReadonly utility type, which when paired with existing manifest types, will modify every field to be read only, ensuring that the type system will help catch accidental modifications to these loaded manifest values as well.

Future work could eliminate these types by modifying the manifest types themselves to be read only, only allowing code that generated them to be writable.

Closes NEXT-3069

[wyattjoh]

• [PPR] Enable incremental adoption #63847
• Freeze loaded manifests #64313 👈
• Shared Revalidate Timings #64370
• canary

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Tests Passed

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Stats from current PR

Default Build

General Overall increase ⚠️

	vercel/next.js canary	vercel/next.js wyattjoh/immutable-prerender-manifest	Change
buildDuration	14s	14s	N/A
buildDurationCached	7.6s	6.3s	N/A
nodeModulesSize	199 MB	199 MB	⚠️ +29.3 kB
nextStartRea..uration (ms)	403ms	409ms	N/A

Client Bundles (main, webpack)

	vercel/next.js canary	vercel/next.js wyattjoh/immutable-prerender-manifest	Change
2453-HASH.js gzip	31.4 kB	31.4 kB	N/A
3304.HASH.js gzip	181 B	181 B	✓
3f784ff6-HASH.js gzip	53.7 kB	53.7 kB	✓
8299-HASH.js gzip	5.1 kB	5.1 kB	N/A
framework-HASH.js gzip	45.2 kB	45.2 kB	✓
main-app-HASH.js gzip	242 B	241 B	N/A
main-HASH.js gzip	32.2 kB	32.2 kB	N/A
webpack-HASH.js gzip	1.68 kB	1.68 kB	N/A
Overall change	99 kB	99 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	vercel/next.js wyattjoh/immutable-prerender-manifest	Change
polyfills-HASH.js gzip	31 kB	31 kB	✓
Overall change	31 kB	31 kB	✓

Client Pages

	vercel/next.js canary	vercel/next.js wyattjoh/immutable-prerender-manifest	Change
_app-HASH.js gzip	196 B	197 B	N/A
_error-HASH.js gzip	184 B	184 B	✓
amp-HASH.js gzip	505 B	505 B	✓
css-HASH.js gzip	324 B	325 B	N/A
dynamic-HASH.js gzip	2.5 kB	2.5 kB	N/A
edge-ssr-HASH.js gzip	258 B	258 B	✓
head-HASH.js gzip	352 B	352 B	✓
hooks-HASH.js gzip	370 B	371 B	N/A
image-HASH.js gzip	4.27 kB	4.27 kB	✓
index-HASH.js gzip	259 B	259 B	✓
link-HASH.js gzip	2.67 kB	2.67 kB	N/A
routerDirect..HASH.js gzip	314 B	312 B	N/A
script-HASH.js gzip	386 B	386 B	✓
withRouter-HASH.js gzip	309 B	309 B	✓
1afbb74e6ecf..834.css gzip	106 B	106 B	✓
Overall change	6.63 kB	6.63 kB	✓

Client Build Manifests

	vercel/next.js canary	vercel/next.js wyattjoh/immutable-prerender-manifest	Change
_buildManifest.js gzip	483 B	485 B	N/A
Overall change	0 B	0 B	✓

Rendered Page Sizes

	vercel/next.js canary	vercel/next.js wyattjoh/immutable-prerender-manifest	Change
index.html gzip	529 B	529 B	✓
link.html gzip	541 B	541 B	✓
withRouter.html gzip	525 B	524 B	N/A
Overall change	1.07 kB	1.07 kB	✓

Edge SSR bundle Size

	vercel/next.js canary	vercel/next.js wyattjoh/immutable-prerender-manifest	Change
edge-ssr.js gzip	95.6 kB	95.6 kB	N/A
page.js gzip	3.06 kB	3.06 kB	✓
Overall change	3.06 kB	3.06 kB	✓

Middleware size

	vercel/next.js canary	vercel/next.js wyattjoh/immutable-prerender-manifest	Change
middleware-b..fest.js gzip	626 B	626 B	✓
middleware-r..fest.js gzip	155 B	156 B	N/A
middleware.js gzip	25.5 kB	25.5 kB	N/A
edge-runtime..pack.js gzip	839 B	839 B	✓
Overall change	1.47 kB	1.47 kB	✓

Next Runtimes

	vercel/next.js canary	vercel/next.js wyattjoh/immutable-prerender-manifest	Change
app-page-exp...dev.js gzip	171 kB	171 kB	✓
app-page-exp..prod.js gzip	97.4 kB	97.4 kB	✓
app-page-tur..prod.js gzip	99.2 kB	99.2 kB	✓
app-page-tur..prod.js gzip	93.4 kB	93.4 kB	✓
app-page.run...dev.js gzip	144 kB	144 kB	✓
app-page.run..prod.js gzip	91.9 kB	91.9 kB	✓
app-route-ex...dev.js gzip	21.4 kB	21.4 kB	✓
app-route-ex..prod.js gzip	15.2 kB	15.2 kB	✓
app-route-tu..prod.js gzip	15.2 kB	15.2 kB	✓
app-route-tu..prod.js gzip	14.9 kB	14.9 kB	✓
app-route.ru...dev.js gzip	21.1 kB	21.1 kB	✓
app-route.ru..prod.js gzip	14.9 kB	14.9 kB	✓
pages-api-tu..prod.js gzip	9.55 kB	9.55 kB	✓
pages-api.ru...dev.js gzip	9.82 kB	9.82 kB	✓
pages-api.ru..prod.js gzip	9.55 kB	9.55 kB	✓
pages-turbo...prod.js gzip	22.5 kB	22.5 kB	✓
pages.runtim...dev.js gzip	23.1 kB	23.1 kB	✓
pages.runtim..prod.js gzip	22.5 kB	22.5 kB	✓
server.runti..prod.js gzip	51.3 kB	51.3 kB	N/A
Overall change	897 kB	897 kB	✓

build cache

	vercel/next.js canary	vercel/next.js wyattjoh/immutable-prerender-manifest	Change
0.pack gzip	1.59 MB	1.58 MB	N/A
index.pack gzip	107 kB	106 kB	N/A
Overall change	0 B	0 B	✓

Diff details

Diff for middleware.js

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Diff for server.runtime.prod.js

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Commit: d90fc32

[ztanner]

Appreciate all the comments 🙏

Would be good to split this into two as discussed! (freeze and SharedRevalidateTimings being separate diffs)