Turbopack: generate less JS before minification

[mischnic]

Use the final __turbopack_context_.X directly, which saves use the long destructuring.
The original versions (__turbopack_load__, __turbopack_import__) are still available as the user-facing API (implemented via free var replacements).

src-rolldown-1000 before:

input_len	6.776151mb
output_len	1.318701mb

src-rolldown-1000 after:

input_len	2.879056mb
output_len	1.147727mb

canary (0f7251fc78):
without sourcemaps:
15,3
506.01s user 104.05s system 780% cpu 1:18.21 total
500.73s user 105.54s system 767% cpu 1:18.98 total

with sourcemaps:
23,3gb
542.87s user 119.60s system 752% cpu 1:28.06 total
537.84s user 117.53s system 799% cpu 1:22.02 total

after (e09b2a5517):
without sourcemaps:
14,65gb
503.89s user 102.31s system 770% cpu 1:18.63 total
493.39s user 100.04s system 768% cpu 1:17.18 total
494.93s user 101.16s system 769% cpu 1:17.44 total

with sourcemaps:
22,7
529.38s user 115.85s system 785% cpu 1:22.09 total
522.39s user 115.70s system 781% cpu 1:21.66 total

Closes PACK-3881

[mischnic]

• Turbopack: generate less JS before minification #75358 👈 (View in Graphite)
• Turbopack: generate shorter variable idents #75611
• canary

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[ijjk]

Tests Passed

[ijjk]

Stats from current PR

Default Build (Increase detected ⚠️)

General

	vercel/next.js canary	vercel/next.js mischnic/less-js	Change
buildDuration	17.8s	16s	N/A
buildDurationCached	15s	13s	N/A
nodeModulesSize	392 MB	392 MB	✓
nextStartRea..uration (ms)	440ms	438ms	N/A

Client Bundles (main, webpack)

	vercel/next.js canary	vercel/next.js mischnic/less-js	Change
5306-HASH.js gzip	54 kB	53.9 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	✓
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	52.9 kB	52.9 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	vercel/next.js mischnic/less-js	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 mischnic/less-js	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 mischnic/less-js	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 mischnic/less-js	Change
index.html gzip	523 B	523 B	✓
link.html gzip	537 B	538 B	N/A
withRouter.html gzip	518 B	519 B	N/A
Overall change	523 B	523 B	✓

Edge SSR bundle Size

	vercel/next.js canary	vercel/next.js mischnic/less-js	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 mischnic/less-js	Change
middleware-b..fest.js gzip	669 B	664 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 mischnic/less-js	Change
app-page-exp...dev.js gzip	386 kB	386 kB	N/A
app-page-exp..prod.js gzip	131 kB	131 kB	✓
app-page-tur..prod.js gzip	144 kB	144 kB	✓
app-page-tur..prod.js gzip	140 kB	140 kB	✓
app-page.run...dev.js gzip	373 kB	373 kB	N/A
app-page.run..prod.js gzip	128 kB	128 kB	✓
app-route-ex...dev.js gzip	39.4 kB	39.4 kB	✓
app-route-ex..prod.js gzip	25 kB	25 kB	✓
app-route-tu..prod.js gzip	25 kB	25 kB	✓
app-route-tu..prod.js gzip	24.8 kB	24.8 kB	✓
app-route.ru...dev.js gzip	41 kB	41 kB	✓
app-route.ru..prod.js gzip	24.8 kB	24.8 kB	✓
dist_client_...dev.js gzip	326 B	326 B	✓
dist_client_...dev.js gzip	318 B	318 B	✓
pages-api-tu..prod.js gzip	8.81 kB	8.81 kB	✓
pages-api.ru...dev.js gzip	11.5 kB	11.5 kB	✓
pages-api.ru..prod.js gzip	8.8 kB	8.8 kB	✓
pages-turbo...prod.js gzip	21.6 kB	21.6 kB	✓
pages.runtim...dev.js gzip	31.3 kB	31.3 kB	N/A
pages.runtim..prod.js gzip	21.6 kB	21.6 kB	✓
server.runti..prod.js gzip	73.7 kB	73.7 kB	✓
Overall change	870 kB	870 kB	✓

build cache Overall increase ⚠️

	vercel/next.js canary	vercel/next.js mischnic/less-js	Change
0.pack gzip	2.1 MB	2.1 MB	⚠️ +4.95 kB
index.pack gzip	75.2 kB	75.7 kB	⚠️ +456 B
Overall change	2.18 MB	2.18 MB	⚠️ +5.4 kB

Diff details

Diff for main-HASH.js

Diff too large to display

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

failed to diff

Diff for app-page.runtime.dev.js

failed to diff

Diff for pages.runtime.dev.js

Diff too large to display

Commit: 3afe10c

[sokra]

I hope .into() doesn't make it a string expression...

[mischnic]

No:

impl Display for TurbopackRuntimeFunctionShortcut {
    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
        f.write_str(self.full)
    }
}

impl From<&TurbopackRuntimeFunctionShortcut> for FreeVarReference {
    fn from(val: &TurbopackRuntimeFunctionShortcut) -> Self {
        FreeVarReference::Member("__turbopack_context__".into(), val.shortcut.into())
    }
}

impl From<&TurbopackRuntimeFunctionShortcut> for Expr {
    fn from(val: &TurbopackRuntimeFunctionShortcut) -> Self {
        Expr::Member(MemberExpr {
            obj: Box::new(Expr::Ident("__turbopack_context__".into())),
            prop: MemberProp::Ident(val.shortcut.into()),
            ..Default::default()
        })
    }
}