Use finally to clean up seen requests

[fmmoret]

Bug

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Feature

• Implements an existing feature request or RFC. Make sure the feature request has been accepted for implementation before opening a PR.
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• Telemetry added. In case of a feature if it's used or not.
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Documentation / Examples

• Make sure the linting passes by running yarn lint

Saw that 1) if an exception in router.execute is ever thrown, next will have a memory leak, 2) this func looks painful to keep leaks out of.

To reviewers: Use PR settings -> diff view -> hide whitespace to see actual changes. Mass indent is hard to reveiw without it. Any lines not related to reference cleanup are just prettier auto-formatting long lines.

[ijjk]

Stats from current PR

Default Build (Increase detected ⚠️)

General Overall increase ⚠️

	vercel/next.js canary	fmmoret/next.js fm-try-finally-router-req-references	Change
buildDuration	17.3s	17.2s	-124ms
buildDurationCached	6.8s	6.8s	-7ms
nodeModulesSize	485 MB	485 MB	⚠️ +608 B

Page Load Tests Overall increase ✓

	vercel/next.js canary	fmmoret/next.js fm-try-finally-router-req-references	Change
/ failed reqs	0	0	✓
/ total time (seconds)	3.687	3.523	-0.16
/ avg req/sec	678.03	709.57	+31.54
/error-in-render failed reqs	0	0	✓
/error-in-render total time (seconds)	1.569	1.508	-0.06
/error-in-render avg req/sec	1593.31	1657.76	+64.45

Client Bundles (main, webpack)

	vercel/next.js canary	fmmoret/next.js fm-try-finally-router-req-references	Change
925.HASH.js gzip	179 B	179 B	✓
framework-HASH.js gzip	42 kB	42 kB	✓
main-HASH.js gzip	28.5 kB	28.5 kB	✓
webpack-HASH.js gzip	1.44 kB	1.44 kB	✓
Overall change	72.1 kB	72.1 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	fmmoret/next.js fm-try-finally-router-req-references	Change
polyfills-HASH.js gzip	31 kB	31 kB	✓
Overall change	31 kB	31 kB	✓

Client Pages

	vercel/next.js canary	fmmoret/next.js fm-try-finally-router-req-references	Change
_app-HASH.js gzip	1.36 kB	1.36 kB	✓
_error-HASH.js gzip	192 B	192 B	✓
amp-HASH.js gzip	309 B	309 B	✓
css-HASH.js gzip	327 B	327 B	✓
dynamic-HASH.js gzip	3.04 kB	3.04 kB	✓
head-HASH.js gzip	351 B	351 B	✓
hooks-HASH.js gzip	920 B	920 B	✓
image-HASH.js gzip	5.74 kB	5.74 kB	✓
index-HASH.js gzip	263 B	263 B	✓
link-HASH.js gzip	2.36 kB	2.36 kB	✓
routerDirect..HASH.js gzip	320 B	320 B	✓
script-HASH.js gzip	392 B	392 B	✓
withRouter-HASH.js gzip	319 B	319 B	✓
85e02e95b279..7e3.css gzip	107 B	107 B	✓
Overall change	16 kB	16 kB	✓

Client Build Manifests

	vercel/next.js canary	fmmoret/next.js fm-try-finally-router-req-references	Change
_buildManifest.js gzip	461 B	461 B	✓
Overall change	461 B	461 B	✓

Rendered Page Sizes

	vercel/next.js canary	fmmoret/next.js fm-try-finally-router-req-references	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	✓

---

Default Build with SWC (Increase detected ⚠️)

General Overall increase ⚠️

	vercel/next.js canary	fmmoret/next.js fm-try-finally-router-req-references	Change
buildDuration	19.8s	19.7s	-123ms
buildDurationCached	6.5s	6.8s	⚠️ +247ms
nodeModulesSize	485 MB	485 MB	⚠️ +608 B

Page Load Tests Overall increase ✓

	vercel/next.js canary	fmmoret/next.js fm-try-finally-router-req-references	Change
/ failed reqs	0	0	✓
/ total time (seconds)	3.659	3.437	-0.22
/ avg req/sec	683.19	727.46	+44.27
/error-in-render failed reqs	0	0	✓
/error-in-render total time (seconds)	1.561	1.522	-0.04
/error-in-render avg req/sec	1601.9	1642.66	+40.76

Client Bundles (main, webpack)

	vercel/next.js canary	fmmoret/next.js fm-try-finally-router-req-references	Change
925.HASH.js gzip	178 B	178 B	✓
framework-HASH.js gzip	42.3 kB	42.3 kB	✓
main-HASH.js gzip	28.9 kB	28.9 kB	✓
webpack-HASH.js gzip	1.45 kB	1.45 kB	✓
Overall change	72.8 kB	72.8 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	fmmoret/next.js fm-try-finally-router-req-references	Change
polyfills-HASH.js gzip	31 kB	31 kB	✓
Overall change	31 kB	31 kB	✓

Client Pages

	vercel/next.js canary	fmmoret/next.js fm-try-finally-router-req-references	Change
_app-HASH.js gzip	1.35 kB	1.35 kB	✓
_error-HASH.js gzip	179 B	179 B	✓
amp-HASH.js gzip	313 B	313 B	✓
css-HASH.js gzip	325 B	325 B	✓
dynamic-HASH.js gzip	3.02 kB	3.02 kB	✓
head-HASH.js gzip	351 B	351 B	✓
hooks-HASH.js gzip	921 B	921 B	✓
image-HASH.js gzip	5.78 kB	5.78 kB	✓
index-HASH.js gzip	261 B	261 B	✓
link-HASH.js gzip	2.44 kB	2.44 kB	✓
routerDirect..HASH.js gzip	322 B	322 B	✓
script-HASH.js gzip	393 B	393 B	✓
withRouter-HASH.js gzip	317 B	317 B	✓
85e02e95b279..7e3.css gzip	107 B	107 B	✓
Overall change	16.1 kB	16.1 kB	✓

Client Build Manifests

	vercel/next.js canary	fmmoret/next.js fm-try-finally-router-req-references	Change
_buildManifest.js gzip	457 B	457 B	✓
Overall change	457 B	457 B	✓

Rendered Page Sizes

	vercel/next.js canary	fmmoret/next.js fm-try-finally-router-req-references	Change
index.html gzip	530 B	530 B	✓
link.html gzip	544 B	544 B	✓
withRouter.html gzip	525 B	525 B	✓
Overall change	1.6 kB	1.6 kB	✓

Commit: 1e42860