use a separate webpack runtime for middleware

[sokra]

it should not leak into the client runtime

cc @javivelasco

Bug

• Related issues linked using fixes #number
• Integration tests added
• Errors have helpful link attached, see contributing.md

Feature

• Implements an existing feature request or RFC. Make sure the feature request has been accepted for implementation before opening a PR.
• Related issues linked using fixes #number
• Integration tests added
• Documentation added
• Telemetry added. In case of a feature if it's used or not.
• Errors have helpful link attached, see contributing.md

Documentation / Examples

• Make sure the linting passes by running yarn lint

[ijjk]

Failing test suites

Commit: 8103be9

test/production/required-server-files.test.ts

• should set-up next > should output middleware correctly

Expand output

● should set-up next › should output middleware correctly

expect(received).toBe(expected) // Object.is equality

Expected: true
Received: false

  85 |     )
  86 |     appPort = await findPort()
> 87 |     server = await initNextServerScript(
     |                                         ^
  88 |       testServer,
  89 |       /Listening on/,
  90 |       {

  at Object.<anonymous> (production/required-server-files.test.ts:87:116)

[ijjk]

Stats from current PR

Default Build (Decrease detected ✓)

General Overall decrease ✓

	vercel/next.js canary	vercel/next.js bugfix/separate-runtime-for-middleware	Change
buildDuration	14.4s	14.4s	⚠️ +8ms
buildDurationCached	3.1s	3.2s	⚠️ +57ms
nodeModulesSize	355 MB	355 MB	-354 B

Page Load Tests Overall decrease ⚠️

	vercel/next.js canary	vercel/next.js bugfix/separate-runtime-for-middleware	Change
/ failed reqs	0	0	✓
/ total time (seconds)	2.877	2.928	⚠️ +0.05
/ avg req/sec	869.04	853.95	⚠️ -15.09
/error-in-render failed reqs	0	0	✓
/error-in-render total time (seconds)	1.335	1.372	⚠️ +0.04
/error-in-render avg req/sec	1872.01	1822.24	⚠️ -49.77

Client Bundles (main, webpack, commons)

	vercel/next.js canary	vercel/next.js bugfix/separate-runtime-for-middleware	Change
450.HASH.js gzip	179 B	179 B	✓
framework-HASH.js gzip	42.2 kB	42.2 kB	✓
main-HASH.js gzip	27.1 kB	27.1 kB	✓
webpack-HASH.js gzip	1.45 kB	1.45 kB	✓
Overall change	70.9 kB	70.9 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	vercel/next.js bugfix/separate-runtime-for-middleware	Change
polyfills-HASH.js gzip	31 kB	31 kB	✓
Overall change	31 kB	31 kB	✓

Client Pages

	vercel/next.js canary	vercel/next.js bugfix/separate-runtime-for-middleware	Change
_app-HASH.js gzip	1.37 kB	1.37 kB	✓
_error-HASH.js gzip	194 B	194 B	✓
amp-HASH.js gzip	312 B	312 B	✓
css-HASH.js gzip	326 B	326 B	✓
dynamic-HASH.js gzip	2.37 kB	2.37 kB	✓
head-HASH.js gzip	350 B	350 B	✓
hooks-HASH.js gzip	919 B	919 B	✓
image-HASH.js gzip	4.74 kB	4.74 kB	✓
index-HASH.js gzip	263 B	263 B	✓
link-HASH.js gzip	2.13 kB	2.13 kB	✓
routerDirect..HASH.js gzip	321 B	321 B	✓
script-HASH.js gzip	383 B	383 B	✓
withRouter-HASH.js gzip	318 B	318 B	✓
85e02e95b279..7e3.css gzip	107 B	107 B	✓
Overall change	14.1 kB	14.1 kB	✓

Client Build Manifests

	vercel/next.js canary	vercel/next.js bugfix/separate-runtime-for-middleware	Change
_buildManifest.js gzip	459 B	459 B	✓
Overall change	459 B	459 B	✓

Rendered Page Sizes

	vercel/next.js canary	vercel/next.js bugfix/separate-runtime-for-middleware	Change
index.html gzip	532 B	532 B	✓
link.html gzip	546 B	546 B	✓
withRouter.html gzip	527 B	527 B	✓
Overall change	1.6 kB	1.6 kB	✓

---

Default Build with SWC (Decrease detected ✓)

General Overall decrease ✓

	vercel/next.js canary	vercel/next.js bugfix/separate-runtime-for-middleware	Change
buildDuration	15.9s	15.8s	-98ms
buildDurationCached	3.2s	3.1s	-6ms
nodeModulesSize	355 MB	355 MB	-354 B

Page Load Tests Overall decrease ⚠️

	vercel/next.js canary	vercel/next.js bugfix/separate-runtime-for-middleware	Change
/ failed reqs	0	0	✓
/ total time (seconds)	2.862	2.896	⚠️ +0.03
/ avg req/sec	873.5	863.4	⚠️ -10.1
/error-in-render failed reqs	0	0	✓
/error-in-render total time (seconds)	1.326	1.337	⚠️ +0.01
/error-in-render avg req/sec	1885.94	1869.72	⚠️ -16.22

Client Bundles (main, webpack, commons)

	vercel/next.js canary	vercel/next.js bugfix/separate-runtime-for-middleware	Change
450.HASH.js gzip	179 B	179 B	✓
framework-HASH.js gzip	42.3 kB	42.3 kB	✓
main-HASH.js gzip	27.2 kB	27.2 kB	✓
webpack-HASH.js gzip	1.44 kB	1.44 kB	✓
Overall change	71.1 kB	71.1 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	vercel/next.js bugfix/separate-runtime-for-middleware	Change
polyfills-HASH.js gzip	31 kB	31 kB	✓
Overall change	31 kB	31 kB	✓

Client Pages

	vercel/next.js canary	vercel/next.js bugfix/separate-runtime-for-middleware	Change
_app-HASH.js gzip	1.35 kB	1.35 kB	✓
_error-HASH.js gzip	180 B	180 B	✓
amp-HASH.js gzip	305 B	305 B	✓
css-HASH.js gzip	321 B	321 B	✓
dynamic-HASH.js gzip	2.36 kB	2.36 kB	✓
head-HASH.js gzip	342 B	342 B	✓
hooks-HASH.js gzip	906 B	906 B	✓
image-HASH.js gzip	4.76 kB	4.76 kB	✓
index-HASH.js gzip	256 B	256 B	✓
link-HASH.js gzip	2.19 kB	2.19 kB	✓
routerDirect..HASH.js gzip	314 B	314 B	✓
script-HASH.js gzip	375 B	375 B	✓
withRouter-HASH.js gzip	309 B	309 B	✓
85e02e95b279..7e3.css gzip	107 B	107 B	✓
Overall change	14.1 kB	14.1 kB	✓

Client Build Manifests

	vercel/next.js canary	vercel/next.js bugfix/separate-runtime-for-middleware	Change
_buildManifest.js gzip	458 B	458 B	✓
Overall change	458 B	458 B	✓

Rendered Page Sizes

	vercel/next.js canary	vercel/next.js bugfix/separate-runtime-for-middleware	Change
index.html gzip	532 B	532 B	✓
link.html gzip	546 B	546 B	✓
withRouter.html gzip	526 B	526 B	✓
Overall change	1.6 kB	1.6 kB	✓

Commit: 2c09f82