Fix server component render condition

[shuding]

We are currently using !!ComponentMod.__next_rsc__ as the hint for the renderer to tell if the component is a server component, however that export field (__next_rsc__) is assigned to client components (.client.[ext]) as well.

This PR adds a new __next_rsc_server__ field which is only true when the component is a server component so the renderer can handle client components correctly.

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

[huozhi]

Do you want to change other places of references of __next_rsc__ as well? Though they're not critical now

[shuding]

@huozhi It depends, AppMod.__next_rsc__ can be changed to AppMod.__next_rsc_server__ but not sure about other places (some are accessed by the client). We can figure this out later.

[ijjk]

Stats from current PR

Default Build (Increase detected ⚠️)

General Overall increase ⚠️

	vercel/next.js canary	shuding/next.js shu/7a80	Change
buildDuration	18.7s	17.8s	-835ms
buildDurationCached	7.1s	7.2s	⚠️ +15ms
nodeModulesSize	467 MB	467 MB	⚠️ +192 B

Page Load Tests Overall increase ✓

	vercel/next.js canary	shuding/next.js shu/7a80	Change
/ failed reqs	0	0	✓
/ total time (seconds)	3.717	3.654	-0.06
/ avg req/sec	672.53	684.27	+11.74
/error-in-render failed reqs	0	0	✓
/error-in-render total time (seconds)	1.67	1.592	-0.08
/error-in-render avg req/sec	1496.92	1570.77	+73.85

Client Bundles (main, webpack)

	vercel/next.js canary	shuding/next.js shu/7a80	Change
925.HASH.js gzip	179 B	179 B	✓
framework-HASH.js gzip	42 kB	42 kB	✓
main-HASH.js gzip	28 kB	28 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/7a80	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/7a80	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	2.57 kB	2.57 kB	✓
head-HASH.js gzip	351 B	351 B	✓
hooks-HASH.js gzip	920 B	920 B	✓
image-HASH.js gzip	5.48 kB	5.48 kB	✓
index-HASH.js gzip	263 B	263 B	✓
link-HASH.js gzip	2.26 kB	2.26 kB	✓
routerDirect..HASH.js gzip	320 B	320 B	✓
script-HASH.js gzip	387 B	387 B	✓
withRouter-HASH.js gzip	319 B	319 B	✓
85e02e95b279..7e3.css gzip	107 B	107 B	✓
Overall change	15.2 kB	15.2 kB	✓

Client Build Manifests

	vercel/next.js canary	shuding/next.js shu/7a80	Change
_buildManifest.js gzip	460 B	460 B	✓
Overall change	460 B	460 B	✓

Rendered Page Sizes

	vercel/next.js canary	shuding/next.js shu/7a80	Change
index.html gzip	531 B	531 B	✓
link.html gzip	544 B	544 B	✓
withRouter.html gzip	525 B	525 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/7a80	Change
buildDuration	21.8s	21.8s	⚠️ +25ms
buildDurationCached	7.3s	7s	-257ms
nodeModulesSize	467 MB	467 MB	⚠️ +192 B

Page Load Tests Overall decrease ⚠️

	vercel/next.js canary	shuding/next.js shu/7a80	Change
/ failed reqs	0	0	✓
/ total time (seconds)	3.598	3.638	⚠️ +0.04
/ avg req/sec	694.93	687.22	⚠️ -7.71
/error-in-render failed reqs	0	0	✓
/error-in-render total time (seconds)	1.523	1.638	⚠️ +0.12
/error-in-render avg req/sec	1641.25	1525.93	⚠️ -115.32

Client Bundles (main, webpack)

	vercel/next.js canary	shuding/next.js shu/7a80	Change
925.HASH.js gzip	178 B	178 B	✓
framework-HASH.js gzip	42.3 kB	42.3 kB	✓
main-HASH.js gzip	28.2 kB	28.2 kB	✓
webpack-HASH.js gzip	1.45 kB	1.45 kB	✓
Overall change	72.1 kB	72.1 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	shuding/next.js shu/7a80	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/7a80	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	324 B	324 B	✓
dynamic-HASH.js gzip	2.56 kB	2.56 kB	✓
head-HASH.js gzip	351 B	351 B	✓
hooks-HASH.js gzip	921 B	921 B	✓
image-HASH.js gzip	5.59 kB	5.59 kB	✓
index-HASH.js gzip	261 B	261 B	✓
link-HASH.js gzip	2.33 kB	2.33 kB	✓
routerDirect..HASH.js gzip	322 B	322 B	✓
script-HASH.js gzip	388 B	388 B	✓
withRouter-HASH.js gzip	317 B	317 B	✓
85e02e95b279..7e3.css gzip	107 B	107 B	✓
Overall change	15.3 kB	15.3 kB	✓

Client Build Manifests

	vercel/next.js canary	shuding/next.js shu/7a80	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/7a80	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: 663d944