Fix flight root failed to hydrate in strict mode

[shuding]

To make sure we refetch the data on client transitions, we remove the flight cache after hydrating the root. However with strict mode enabled, the hydration process (initial render) will be invoked twice before hydration ends. This PR moves the cache clean up logic to an effect so we only do that after the successful hydration (and every rerender).

Changed tests to enable strict mode to ensure it works.

Relies on #34338.

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

[shuding]

Noticed two bugs of RouteAnnouncer due to the failed tests, need to fix them first.

[ijjk]

Stats from current PR

Default Build (Decrease detected ✓)

General Overall increase ⚠️

	vercel/next.js canary	shuding/next.js shu/ebd2	Change
buildDuration	15.5s	15.4s	-82ms
buildDurationCached	6s	6s	-26ms
nodeModulesSize	359 MB	359 MB	⚠️ +110 B

Page Load Tests Overall decrease ⚠️

	vercel/next.js canary	shuding/next.js shu/ebd2	Change
/ failed reqs	0	0	✓
/ total time (seconds)	3.032	3.089	⚠️ +0.06
/ avg req/sec	824.63	809.2	⚠️ -15.43
/error-in-render failed reqs	0	0	✓
/error-in-render total time (seconds)	1.216	1.21	-0.01
/error-in-render avg req/sec	2056.64	2066.89	+10.25

Client Bundles (main, webpack, commons)

	vercel/next.js canary	shuding/next.js shu/ebd2	Change
450.HASH.js gzip	179 B	179 B	✓
framework-HASH.js gzip	42 kB	42 kB	✓
main-HASH.js gzip	27.9 kB	27.9 kB	✓
webpack-HASH.js gzip	1.44 kB	1.44 kB	✓
Overall change	71.5 kB	71.5 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	shuding/next.js shu/ebd2	Change
polyfills-HASH.js gzip	31 kB	31 kB	✓
Overall change	31 kB	31 kB	✓

Client Pages

	vercel/next.js canary	shuding/next.js shu/ebd2	Change
_app-HASH.js gzip	1.36 kB	1.36 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	2.57 kB	2.57 kB	✓
head-HASH.js gzip	350 B	350 B	✓
hooks-HASH.js gzip	919 B	919 B	✓
image-HASH.js gzip	5.01 kB	5.01 kB	✓
index-HASH.js gzip	263 B	263 B	✓
link-HASH.js gzip	2.26 kB	2.26 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	14.7 kB	14.7 kB	✓

Client Build Manifests

	vercel/next.js canary	shuding/next.js shu/ebd2	Change
_buildManifest.js gzip	459 B	459 B	✓
Overall change	459 B	459 B	✓

Rendered Page Sizes

	vercel/next.js canary	shuding/next.js shu/ebd2	Change
index.html gzip	532 B	532 B	✓
link.html gzip	545 B	545 B	✓
withRouter.html gzip	526 B	526 B	✓
Overall change	1.6 kB	1.6 kB	✓

---

Default Build with SWC (Decrease detected ✓)

General Overall increase ⚠️

	vercel/next.js canary	shuding/next.js shu/ebd2	Change
buildDuration	19.2s	18.8s	-388ms
buildDurationCached	6.1s	6s	-99ms
nodeModulesSize	359 MB	359 MB	⚠️ +484 B

Page Load Tests Overall decrease ⚠️

	vercel/next.js canary	shuding/next.js shu/ebd2	Change
/ failed reqs	0	0	✓
/ total time (seconds)	3.056	3.076	⚠️ +0.02
/ avg req/sec	818.04	812.83	⚠️ -5.21
/error-in-render failed reqs	0	0	✓
/error-in-render total time (seconds)	1.218	1.24	⚠️ +0.02
/error-in-render avg req/sec	2051.89	2016.89	⚠️ -35

Client Bundles (main, webpack, commons)

	vercel/next.js canary	shuding/next.js shu/ebd2	Change
450.HASH.js gzip	179 B	179 B	✓
framework-HASH.js gzip	42.1 kB	42.1 kB	✓
main-HASH.js gzip	27.9 kB	27.9 kB	✓
webpack-HASH.js gzip	1.44 kB	1.44 kB	✓
Overall change	71.6 kB	71.6 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	shuding/next.js shu/ebd2	Change
polyfills-HASH.js gzip	31 kB	31 kB	✓
Overall change	31 kB	31 kB	✓

Client Pages

	vercel/next.js canary	shuding/next.js shu/ebd2	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	2.56 kB	2.56 kB	✓
head-HASH.js gzip	342 B	342 B	✓
hooks-HASH.js gzip	911 B	911 B	✓
image-HASH.js gzip	5.05 kB	5.05 kB	✓
index-HASH.js gzip	256 B	256 B	✓
link-HASH.js gzip	2.28 kB	2.28 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	14.7 kB	14.7 kB	✓

Client Build Manifests

	vercel/next.js canary	shuding/next.js shu/ebd2	Change
_buildManifest.js gzip	458 B	458 B	✓
Overall change	458 B	458 B	✓

Rendered Page Sizes

	vercel/next.js canary	shuding/next.js shu/ebd2	Change
index.html gzip	533 B	533 B	✓
link.html gzip	546 B	546 B	✓
withRouter.html gzip	527 B	527 B	✓
Overall change	1.61 kB	1.61 kB	✓

Commit: 3c9757b

[ijjk]

Failing test suites

Commit: 3c9757b

yarn testheadless test/integration/image-optimizer/test/sharp.test.js

• with latest sharp > Server support with next.config.js > should use cached image file when parameters are the same for animated gif

Expand output

● with latest sharp › Server support with next.config.js › should use cached image file when parameters are the same for animated gif

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

Expected: "HIT"
Received: "MISS"

  837 |     const res2 = await fetchViaHTTP(ctx.appPort, '/_next/image', query, opts)
  838 |     expect(res2.status).toBe(200)
> 839 |     expect(res2.headers.get('X-Nextjs-Cache')).toBe('HIT')
      |                                                ^
  840 |     expect(res2.headers.get('Content-Type')).toBe('image/gif')
  841 |     expect(res2.headers.get('Content-Disposition')).toBe(
  842 |       `inline; filename="animated.gif"`

  at Object.<anonymous> (integration/image-optimizer/test/util.js:839:48)

Read more about building and testing Next.js in contributing.md.

[huozhi]

Noice