Don't import typescript at runtime

[mischnic]

Closes #86981
Closes PACK-6209

Don't import typescript at runtime to determine the tsconfig, to be able to transpile next.config.ts.

Instead, read the tsconfig file directly.

[mischnic]

• Don't import typescript at runtime #88321 👈 (View in Graphite)
• Turbopack: improve next-server.nft.json tests #88320 : 1 other dependent PR (#88322 )
• canary

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[vercel]

Notifying the following users due to files changed in this PR based on this repo's notify modifiers:

@timneutkens, @ijjk, @shuding, @huozhi:

packages/next/src/server/config.ts

[nextjs-bot]

Tests Passed

[nextjs-bot]

Stats from current PR

✅ No significant changes detected

📊 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)	454ms	455ms	✓	▁▁▁▁▁
Cold (First Request)	1.094s	1.136s	✓	▁█▁██
Warm (Listen)	456ms	456ms	✓	▁▁▁▁▁
Warm (First Request)	336ms	334ms	✓	▅▆▅▁▁

📦 Dev Server (Webpack) (Legacy)

📦 Dev Server (Webpack)

Metric	Canary	PR	Change	Trend
Cold (Listen)	455ms	455ms	✓	▁██▁▁
Cold (First Request)	1.741s	1.752s	✓	▄▁█▅▄
Warm (Listen)	456ms	455ms	✓	▅▅▅▅▁
Warm (First Request)	1.739s	1.755s	✓	▅▁█▅▄

⚡ Production Builds

Metric	Canary	PR	Change	Trend
Fresh Build	4.073s	4.009s	✓	▂▁▅▁▁
Cached Build	4.032s	4.044s	✓	▂▁▃▁▂

📦 Production Builds (Webpack) (Legacy)

📦 Production Builds (Webpack)

Metric	Canary	PR	Change	Trend
Fresh Build	13.851s	13.858s	✓	▂▁█▂▁
Cached Build	13.875s	13.923s	✓	▂▁█▁▁
node_modules Size	457 MB	457 MB	✓	▇▇▇▇█

📦 Bundle Sizes

Bundle Sizes

⚡ Turbopack

Client

Main Bundles: **430 kB** → **430 kB** ✅ -4 B

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

Server

Middleware

	Canary	PR	Change
middleware-b..fest.js gzip	793 B	796 B	✓
Total	793 B	796 B	⚠️ +3 B

Build Details

Build Manifests

	Canary	PR	Change
_buildManifest.js gzip	449 B	450 B	✓
Total	449 B	450 B	⚠️ +1 B

📦 Webpack

Client

Main Bundles

	Canary	PR	Change
2086.HASH.js gzip	169 B	N/A	-
2161-HASH.js gzip	5.41 kB	N/A	-
2747-HASH.js gzip	4.48 kB	N/A	-
4322-HASH.js gzip	52.7 kB	N/A	-
ec793fe8-HASH.js gzip	62.3 kB	N/A	-
framework-HASH.js gzip	59.8 kB	59.8 kB	✓
main-app-HASH.js gzip	251 B	253 B	✓
main-HASH.js gzip	38.6 kB	39 kB	✓
webpack-HASH.js gzip	1.68 kB	1.68 kB	✓
1596.HASH.js gzip	N/A	169 B	-
2658-HASH.js gzip	N/A	52.5 kB	-
6349-HASH.js gzip	N/A	4.46 kB	-
7019-HASH.js gzip	N/A	5.43 kB	-
b17a3386-HASH.js gzip	N/A	62.3 kB	-
Total	225 kB	225 kB	⚠️ +156 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	193 B	✓
_error-HASH.js gzip	182 B	182 B	✓
css-HASH.js gzip	336 B	335 B	✓
dynamic-HASH.js gzip	1.8 kB	1.8 kB	✓
edge-ssr-HASH.js gzip	256 B	256 B	✓
head-HASH.js gzip	352 B	349 B	✓
hooks-HASH.js gzip	385 B	384 B	✓
image-HASH.js gzip	580 B	580 B	✓
index-HASH.js gzip	259 B	258 B	✓
link-HASH.js gzip	2.5 kB	2.51 kB	✓
routerDirect..HASH.js gzip	319 B	317 B	✓
script-HASH.js gzip	385 B	387 B	✓
withRouter-HASH.js gzip	316 B	315 B	✓
1afbb74e6ecf..834.css gzip	106 B	106 B	✓
Total	7.97 kB	7.96 kB	✅ -8 B

Server

Edge SSR

	Canary	PR	Change
edge-ssr.js gzip	125 kB	125 kB	✓
page.js gzip	239 kB	239 kB	✓
Total	364 kB	364 kB	⚠️ +273 B

Middleware

	Canary	PR	Change
middleware-b..fest.js gzip	653 B	654 B	✓
middleware-r..fest.js gzip	155 B	156 B	✓
middleware.js gzip	32.9 kB	33.1 kB	✓
edge-runtime..pack.js gzip	842 B	842 B	✓
Total	34.5 kB	34.8 kB	⚠️ +236 B

Build Details

Build Manifests

	Canary	PR	Change
_buildManifest.js gzip	738 B	738 B	✓
Total	738 B	738 B	✓

Build Cache

	Canary	PR	Change
0.pack gzip	3.61 MB	3.61 MB	✓
index.pack gzip	98.9 kB	98.5 kB	✓
index.pack.old gzip	99.5 kB	98.9 kB	✓
Total	3.81 MB	3.81 MB	⚠️ +148 B

🔄 Shared (bundler-independent)

Runtimes

	Canary	PR	Change
app-page-exp...dev.js gzip	303 kB	303 kB	✓
app-page-exp..prod.js gzip	157 kB	157 kB	✓
app-page-tur...dev.js gzip	302 kB	302 kB	✓
app-page-tur..prod.js gzip	157 kB	157 kB	✓
app-page-tur...dev.js gzip	299 kB	299 kB	✓
app-page-tur..prod.js gzip	155 kB	155 kB	✓
app-page.run...dev.js gzip	299 kB	299 kB	✓
app-page.run..prod.js gzip	155 kB	155 kB	✓
app-route-ex...dev.js gzip	68.2 kB	68.2 kB	✓
app-route-ex..prod.js gzip	46.9 kB	46.9 kB	✓
app-route-tu...dev.js gzip	68.2 kB	68.2 kB	✓
app-route-tu..prod.js gzip	46.9 kB	46.9 kB	✓
app-route-tu...dev.js gzip	67.8 kB	67.8 kB	✓
app-route-tu..prod.js gzip	46.7 kB	46.7 kB	✓
app-route.ru...dev.js gzip	67.8 kB	67.8 kB	✓
app-route.ru..prod.js gzip	46.7 kB	46.7 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	41.1 kB	41.1 kB	✓
pages-api-tu..prod.js gzip	31.2 kB	31.2 kB	✓
pages-api.ru...dev.js gzip	41.1 kB	41.1 kB	✓
pages-api.ru..prod.js gzip	31.2 kB	31.2 kB	✓
pages-turbo....dev.js gzip	50.8 kB	50.8 kB	✓
pages-turbo...prod.js gzip	38.2 kB	38.2 kB	✓
pages.runtim...dev.js gzip	50.8 kB	50.8 kB	✓
pages.runtim..prod.js gzip	38.2 kB	38.2 kB	✓
server.runti..prod.js gzip	62 kB	62 kB	✓
Total	2.67 MB	2.67 MB	⚠️ +4 B