Refactor incremental cache to be extensible

[ijjk]

This refactors the incremental-cache and moves the file-system cache handling to it's own cache handler allowing it to be replaced by a custom cache handler (experimental).

Closes: #22619

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
• The examples guidelines are followed from our contributing doc

[ijjk]

Stats from current PR

Default Build (Decrease detected ✓)

General Overall increase ⚠️

	vercel/next.js canary	ijjk/next.js update/refactor-incremental-cache	Change
buildDuration	21s	20.9s	-69ms
buildDurationCached	8s	8s	⚠️ +16ms
nodeModulesSize	626 MB	626 MB	⚠️ +3.58 kB

Page Load Tests Overall decrease ⚠️

	vercel/next.js canary	ijjk/next.js update/refactor-incremental-cache	Change
/ failed reqs	0	0	✓
/ total time (seconds)	5.528	5.521	-0.01
/ avg req/sec	452.23	452.83	+0.6
/error-in-render failed reqs	0	0	✓
/error-in-render total time (seconds)	2.226	2.282	⚠️ +0.06
/error-in-render avg req/sec	1123.21	1095.64	⚠️ -27.57

Client Bundles (main, webpack)

	vercel/next.js canary	ijjk/next.js update/refactor-incremental-cache	Change
925.HASH.js gzip	179 B	179 B	✓
framework-HASH.js gzip	42 kB	42 kB	✓
main-HASH.js gzip	29.2 kB	29.2 kB	✓
webpack-HASH.js gzip	1.54 kB	1.54 kB	✓
Overall change	72.9 kB	72.9 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	ijjk/next.js update/refactor-incremental-cache	Change
polyfills-HASH.js gzip	31 kB	31 kB	✓
Overall change	31 kB	31 kB	✓

Client Pages

	vercel/next.js canary	ijjk/next.js update/refactor-incremental-cache	Change
_app-HASH.js gzip	1.36 kB	1.36 kB	✓
_error-HASH.js gzip	193 B	193 B	✓
amp-HASH.js gzip	308 B	308 B	✓
css-HASH.js gzip	327 B	327 B	✓
dynamic-HASH.js gzip	2.7 kB	2.7 kB	✓
head-HASH.js gzip	359 B	359 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	2.65 kB	2.65 kB	✓
routerDirect..HASH.js gzip	320 B	320 B	✓
script-HASH.js gzip	391 B	391 B	✓
withRouter-HASH.js gzip	318 B	318 B	✓
85e02e95b279..7e3.css gzip	107 B	107 B	✓
Overall change	16 kB	16 kB	✓

Client Build Manifests

	vercel/next.js canary	ijjk/next.js update/refactor-incremental-cache	Change
_buildManifest.js gzip	459 B	459 B	✓
Overall change	459 B	459 B	✓

Rendered Page Sizes

	vercel/next.js canary	ijjk/next.js update/refactor-incremental-cache	Change
index.html gzip	533 B	533 B	✓
link.html gzip	547 B	547 B	✓
withRouter.html gzip	528 B	528 B	✓
Overall change	1.61 kB	1.61 kB	✓

---

Default Build with SWC (Decrease detected ✓)

General Overall increase ⚠️

	vercel/next.js canary	ijjk/next.js update/refactor-incremental-cache	Change
buildDuration	23.9s	24.1s	⚠️ +179ms
buildDurationCached	8s	7.9s	-126ms
nodeModulesSize	626 MB	626 MB	⚠️ +3.58 kB

Page Load Tests Overall decrease ⚠️

	vercel/next.js canary	ijjk/next.js update/refactor-incremental-cache	Change
/ failed reqs	0	0	✓
/ total time (seconds)	5.443	5.481	⚠️ +0.04
/ avg req/sec	459.29	456.1	⚠️ -3.19
/error-in-render failed reqs	0	0	✓
/error-in-render total time (seconds)	2.19	2.248	⚠️ +0.06
/error-in-render avg req/sec	1141.8	1112.01	⚠️ -29.79

Client Bundles (main, webpack)

	vercel/next.js canary	ijjk/next.js update/refactor-incremental-cache	Change
925.HASH.js gzip	178 B	178 B	✓
framework-HASH.js gzip	42.7 kB	42.7 kB	✓
main-HASH.js gzip	29.7 kB	29.7 kB	✓
webpack-HASH.js gzip	1.54 kB	1.54 kB	✓
Overall change	74 kB	74 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	ijjk/next.js update/refactor-incremental-cache	Change
polyfills-HASH.js gzip	31 kB	31 kB	✓
Overall change	31 kB	31 kB	✓

Client Pages

	vercel/next.js canary	ijjk/next.js update/refactor-incremental-cache	Change
_app-HASH.js gzip	1.35 kB	1.35 kB	✓
_error-HASH.js gzip	179 B	179 B	✓
amp-HASH.js gzip	311 B	311 B	✓
css-HASH.js gzip	324 B	324 B	✓
dynamic-HASH.js gzip	2.9 kB	2.9 kB	✓
head-HASH.js gzip	357 B	357 B	✓
hooks-HASH.js gzip	920 B	920 B	✓
image-HASH.js gzip	5.84 kB	5.84 kB	✓
index-HASH.js gzip	261 B	261 B	✓
link-HASH.js gzip	2.78 kB	2.78 kB	✓
routerDirect..HASH.js gzip	322 B	322 B	✓
script-HASH.js gzip	392 B	392 B	✓
withRouter-HASH.js gzip	317 B	317 B	✓
85e02e95b279..7e3.css gzip	107 B	107 B	✓
Overall change	16.4 kB	16.4 kB	✓

Client Build Manifests

	vercel/next.js canary	ijjk/next.js update/refactor-incremental-cache	Change
_buildManifest.js gzip	458 B	458 B	✓
Overall change	458 B	458 B	✓

Rendered Page Sizes

	vercel/next.js canary	ijjk/next.js update/refactor-incremental-cache	Change
index.html gzip	532 B	532 B	✓
link.html gzip	546 B	546 B	✓
withRouter.html gzip	528 B	528 B	✓
Overall change	1.61 kB	1.61 kB	✓

Commit: 7401927

[PizzaPete]

Is there any documentation about this feature?

[timneutkens]

Experimental features are intentionally not documented as they can change at any time until they are released as stable.