Fix create-next-app failing without yarn installed

[ijjk]

This fixes our package manager detection which was changed slightly in #34947 for pnpm support to ensure the default case still attempts detecting the available package manager if no preference is specified in the command args. This also adds a test case to ensure the install succeeds when we fail to detect a valid yarn binary and no preference is set via the npm_config_user_agent env variable.

Bug

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

Fixes: #35607
Fixes: #35599
Fixes: #35611

[ijjk]

Stats from current PR

Default Build (Decrease detected ✓)

General

	vercel/next.js canary	ijjk/next.js fix/cna-yarn	Change
buildDuration	20.5s	20.7s	⚠️ +204ms
buildDurationCached	7.8s	7.8s	⚠️ +52ms
nodeModulesSize	467 MB	467 MB	✓

Page Load Tests Overall decrease ⚠️

	vercel/next.js canary	ijjk/next.js fix/cna-yarn	Change
/ failed reqs	0	0	✓
/ total time (seconds)	4.481	4.354	-0.13
/ avg req/sec	557.96	574.2	+16.24
/error-in-render failed reqs	0	0	✓
/error-in-render total time (seconds)	2.109	2.199	⚠️ +0.09
/error-in-render avg req/sec	1185.3	1137.06	⚠️ -48.24

Client Bundles (main, webpack)

	vercel/next.js canary	ijjk/next.js fix/cna-yarn	Change
925.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	71.6 kB	71.6 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	ijjk/next.js fix/cna-yarn	Change
polyfills-HASH.js gzip	31 kB	31 kB	✓
Overall change	31 kB	31 kB	✓

Client Pages

	vercel/next.js canary	ijjk/next.js fix/cna-yarn	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	ijjk/next.js fix/cna-yarn	Change
_buildManifest.js gzip	460 B	460 B	✓
Overall change	460 B	460 B	✓

Rendered Page Sizes

	vercel/next.js canary	ijjk/next.js fix/cna-yarn	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 (Decrease detected ✓)

General

	vercel/next.js canary	ijjk/next.js fix/cna-yarn	Change
buildDuration	23.9s	25.5s	⚠️ +1.5s
buildDurationCached	7.8s	7.7s	-134ms
nodeModulesSize	467 MB	467 MB	✓

Page Load Tests Overall decrease ⚠️

	vercel/next.js canary	ijjk/next.js fix/cna-yarn	Change
/ failed reqs	0	0	✓
/ total time (seconds)	4.322	4.514	⚠️ +0.19
/ avg req/sec	578.49	553.79	⚠️ -24.7
/error-in-render failed reqs	0	0	✓
/error-in-render total time (seconds)	2.145	2.145	✓
/error-in-render avg req/sec	1165.55	1165.6	+0.05

Client Bundles (main, webpack)

	vercel/next.js canary	ijjk/next.js fix/cna-yarn	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	ijjk/next.js fix/cna-yarn	Change
polyfills-HASH.js gzip	31 kB	31 kB	✓
Overall change	31 kB	31 kB	✓

Client Pages

	vercel/next.js canary	ijjk/next.js fix/cna-yarn	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	ijjk/next.js fix/cna-yarn	Change
_buildManifest.js gzip	458 B	458 B	✓
Overall change	458 B	458 B	✓

Rendered Page Sizes

	vercel/next.js canary	ijjk/next.js fix/cna-yarn	Change
index.html gzip	531 B	531 B	✓
link.html gzip	545 B	545 B	✓
withRouter.html gzip	527 B	527 B	✓
Overall change	1.6 kB	1.6 kB	✓

Commit: 977b9cf