Ensure externals are correct for mini-css-extract-plugin

[ijjk]

This ensures we map to the correct external files while pre-compiling the mini-css-extract-plugin and also ensures we provide the NormalModule under the webpack require hook.

Bug

• Related issues linked using fixes #number
• Integration tests added

Fixes: #25276 (comment)

[ijjk]

Stats from current PR

Default Server Mode (Increase detected ⚠️)

General Overall increase ⚠️

	vercel/next.js canary	ijjk/next.js fix/compiled-css-extract-plugin	Change
buildDuration	14.1s	13.7s	-387ms
buildDurationCached	4s	3.6s	-351ms
nodeModulesSize	46.7 MB	46.7 MB	⚠️ +193 B

Page Load Tests Overall increase ✓

	vercel/next.js canary	ijjk/next.js fix/compiled-css-extract-plugin	Change
/ failed reqs	0	0	✓
/ total time (seconds)	2.469	2.38	-0.09
/ avg req/sec	1012.52	1050.2	+37.68
/error-in-render failed reqs	0	0	✓
/error-in-render total time (seconds)	1.255	1.259	0
/error-in-render avg req/sec	1992.81	1985.2	⚠️ -7.61

Client Bundles (main, webpack, commons)

	vercel/next.js canary	ijjk/next.js fix/compiled-css-extract-plugin	Change
framework-HASH.js gzip	39.3 kB	39.3 kB	✓
main-HASH.js gzip	19.4 kB	19.4 kB	✓
webpack-HASH.js gzip	994 B	994 B	✓
Overall change	59.7 kB	59.7 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	ijjk/next.js fix/compiled-css-extract-plugin	Change
polyfills-HASH.js gzip	31.1 kB	31.1 kB	✓
Overall change	31.1 kB	31.1 kB	✓

Client Pages

	vercel/next.js canary	ijjk/next.js fix/compiled-css-extract-plugin	Change
_app-HASH.js gzip	1.02 kB	1.02 kB	✓
_error-HASH.js gzip	3.06 kB	3.06 kB	✓
amp-HASH.js gzip	526 B	526 B	✓
css-HASH.js gzip	334 B	334 B	✓
hooks-HASH.js gzip	890 B	890 B	✓
index-HASH.js gzip	262 B	262 B	✓
link-HASH.js gzip	1.65 kB	1.65 kB	✓
routerDirect..HASH.js gzip	331 B	331 B	✓
withRouter-HASH.js gzip	329 B	329 B	✓
bb14e60e810b..30f.css gzip	125 B	125 B	✓
Overall change	8.54 kB	8.54 kB	✓

Client Build Manifests

	vercel/next.js canary	ijjk/next.js fix/compiled-css-extract-plugin	Change
_buildManifest.js gzip	390 B	390 B	✓
Overall change	390 B	390 B	✓

Rendered Page Sizes

	vercel/next.js canary	ijjk/next.js fix/compiled-css-extract-plugin	Change
index.html gzip	559 B	559 B	✓
link.html gzip	567 B	567 B	✓
withRouter.html gzip	555 B	555 B	✓
Overall change	1.68 kB	1.68 kB	✓

---

Serverless Mode

General Overall increase ⚠️

	vercel/next.js canary	ijjk/next.js fix/compiled-css-extract-plugin	Change
buildDuration	15.8s	15.8s	-28ms
buildDurationCached	4.9s	4.8s	-88ms
nodeModulesSize	46.7 MB	46.7 MB	⚠️ +193 B

Client Bundles (main, webpack, commons)

	vercel/next.js canary	ijjk/next.js fix/compiled-css-extract-plugin	Change
framework-HASH.js gzip	39.3 kB	39.3 kB	✓
main-HASH.js gzip	19.4 kB	19.4 kB	✓
webpack-HASH.js gzip	994 B	994 B	✓
Overall change	59.7 kB	59.7 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	ijjk/next.js fix/compiled-css-extract-plugin	Change
polyfills-HASH.js gzip	31.1 kB	31.1 kB	✓
Overall change	31.1 kB	31.1 kB	✓

Client Pages

	vercel/next.js canary	ijjk/next.js fix/compiled-css-extract-plugin	Change
_app-HASH.js gzip	1.02 kB	1.02 kB	✓
_error-HASH.js gzip	3.06 kB	3.06 kB	✓
amp-HASH.js gzip	526 B	526 B	✓
css-HASH.js gzip	334 B	334 B	✓
hooks-HASH.js gzip	890 B	890 B	✓
index-HASH.js gzip	262 B	262 B	✓
link-HASH.js gzip	1.65 kB	1.65 kB	✓
routerDirect..HASH.js gzip	331 B	331 B	✓
withRouter-HASH.js gzip	329 B	329 B	✓
bb14e60e810b..30f.css gzip	125 B	125 B	✓
Overall change	8.54 kB	8.54 kB	✓

Client Build Manifests

	vercel/next.js canary	ijjk/next.js fix/compiled-css-extract-plugin	Change
_buildManifest.js gzip	390 B	390 B	✓
Overall change	390 B	390 B	✓

Serverless bundles

	vercel/next.js canary	ijjk/next.js fix/compiled-css-extract-plugin	Change
_error.js	16.9 kB	16.9 kB	✓
404.html	2.42 kB	2.42 kB	✓
500.html	2.41 kB	2.41 kB	✓
amp.amp.html	10.8 kB	10.8 kB	✓
amp.html	1.61 kB	1.61 kB	✓
css.html	1.79 kB	1.79 kB	✓
hooks.html	1.67 kB	1.67 kB	✓
index.js	17.2 kB	17.2 kB	✓
link.js	17.4 kB	17.4 kB	✓
routerDirect.js	17.4 kB	17.4 kB	✓
withRouter.js	17.4 kB	17.4 kB	✓
Overall change	107 kB	107 kB	✓

---

Webpack 4 Mode (Decrease detected ✓)

General Overall increase ⚠️

	vercel/next.js canary	ijjk/next.js fix/compiled-css-extract-plugin	Change
buildDuration	12.9s	12.7s	-230ms
buildDurationCached	5.3s	5.3s	-60ms
nodeModulesSize	46.7 MB	46.7 MB	⚠️ +193 B

Page Load Tests Overall decrease ⚠️

	vercel/next.js canary	ijjk/next.js fix/compiled-css-extract-plugin	Change
/ failed reqs	0	0	✓
/ total time (seconds)	2.36	2.438	⚠️ +0.08
/ avg req/sec	1059.4	1025.32	⚠️ -34.08
/error-in-render failed reqs	0	0	✓
/error-in-render total time (seconds)	1.301	1.35	⚠️ +0.05
/error-in-render avg req/sec	1922.06	1852	⚠️ -70.06

Client Bundles (main, webpack, commons)

	vercel/next.js canary	ijjk/next.js fix/compiled-css-extract-plugin	Change
677f882d2ed8..HASH.js gzip	13.3 kB	13.3 kB	✓
framework.HASH.js gzip	39 kB	39 kB	✓
main-HASH.js gzip	7.25 kB	7.25 kB	✓
webpack-HASH.js gzip	751 B	751 B	✓
Overall change	60.3 kB	60.3 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	ijjk/next.js fix/compiled-css-extract-plugin	Change
polyfills-HASH.js gzip	31.3 kB	31.3 kB	✓
Overall change	31.3 kB	31.3 kB	✓

Client Pages

	vercel/next.js canary	ijjk/next.js fix/compiled-css-extract-plugin	Change
_app-HASH.js gzip	1.28 kB	1.28 kB	✓
_error-HASH.js gzip	3.74 kB	3.74 kB	✓
amp-HASH.js gzip	536 B	536 B	✓
css-HASH.js gzip	339 B	339 B	✓
hooks-HASH.js gzip	887 B	887 B	✓
index-HASH.js gzip	227 B	227 B	✓
link-HASH.js gzip	1.64 kB	1.64 kB	✓
routerDirect..HASH.js gzip	303 B	303 B	✓
withRouter-HASH.js gzip	302 B	302 B	✓
e025d2764813..52f.css gzip	125 B	125 B	✓
Overall change	9.38 kB	9.38 kB	✓

Client Build Manifests

	vercel/next.js canary	ijjk/next.js fix/compiled-css-extract-plugin	Change
_buildManifest.js gzip	420 B	420 B	✓
Overall change	420 B	420 B	✓

Rendered Page Sizes

	vercel/next.js canary	ijjk/next.js fix/compiled-css-extract-plugin	Change
index.html gzip	613 B	613 B	✓
link.html gzip	619 B	619 B	✓
withRouter.html gzip	607 B	607 B	✓
Overall change	1.84 kB	1.84 kB	✓

Commit: 11e8ab3