fix: avoid race condition when download swc wasm

[d3lm]

What?

I noticed that code that was responsible for download the SWC Wasm fallback wasn't bullet proof and there was a chance for a race condition. The reason was that both write and close from a write stream are async operations and it's best to wait for them to complete, otherwise the promise returned from body.pipeTo could resolve before all data has been written and the stream was closed. Right after that it calls rename and it could happen that, at that point, tempFile doesn't contain all the data yet which means an empty file may be renamed into another file ending up with path.join(cacheDirectory, tarFileName) being empty as well.

The fix is to wait for both write and close to be completed which eliminates the potential race condition between the fetch and the rename.

[ijjk]

Allow CI Workflow Run

• approve CI run for commit: 13af30b

Note: this should only be enabled once the PR is ready to go and can only be enabled by a maintainer

[ijjk]

Allow CI Workflow Run

• approve CI run for commit: 13af30b

Note: this should only be enabled once the PR is ready to go and can only be enabled by a maintainer

[ijjk]

Stats from current PR

Default Build

General Overall increase ⚠️

	vercel/next.js canary	d3lm/next.js delm/fix/downloading-of-wasm	Change
buildDuration	10.7s	10.5s	N/A
buildDurationCached	6s	6.7s	⚠️ +633ms
nodeModulesSize	199 MB	199 MB	⚠️ +3.1 kB
nextStartRea..uration (ms)	429ms	430ms	N/A

Client Bundles (main, webpack)

	vercel/next.js canary	d3lm/next.js delm/fix/downloading-of-wasm	Change
199-HASH.js gzip	28.7 kB	28.7 kB	N/A
3f784ff6-HASH.js gzip	53.3 kB	53.3 kB	✓
494.HASH.js gzip	180 B	181 B	N/A
framework-HASH.js gzip	45.2 kB	45.2 kB	✓
main-app-HASH.js gzip	242 B	239 B	N/A
main-HASH.js gzip	31.7 kB	31.7 kB	N/A
webpack-HASH.js gzip	1.7 kB	1.7 kB	✓
Overall change	100 kB	100 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	d3lm/next.js delm/fix/downloading-of-wasm	Change
polyfills-HASH.js gzip	31 kB	31 kB	✓
Overall change	31 kB	31 kB	✓

Client Pages

	vercel/next.js canary	d3lm/next.js delm/fix/downloading-of-wasm	Change
_app-HASH.js gzip	194 B	195 B	N/A
_error-HASH.js gzip	182 B	181 B	N/A
amp-HASH.js gzip	501 B	503 B	N/A
css-HASH.js gzip	322 B	323 B	N/A
dynamic-HASH.js gzip	2.5 kB	2.5 kB	✓
edge-ssr-HASH.js gzip	253 B	255 B	N/A
head-HASH.js gzip	348 B	347 B	N/A
hooks-HASH.js gzip	369 B	368 B	N/A
image-HASH.js gzip	4.28 kB	4.27 kB	N/A
index-HASH.js gzip	256 B	256 B	✓
link-HASH.js gzip	2.61 kB	2.6 kB	N/A
routerDirect..HASH.js gzip	311 B	311 B	✓
script-HASH.js gzip	384 B	383 B	N/A
withRouter-HASH.js gzip	307 B	308 B	N/A
1afbb74e6ecf..834.css gzip	106 B	106 B	✓
Overall change	3.17 kB	3.17 kB	✓

Client Build Manifests

	vercel/next.js canary	d3lm/next.js delm/fix/downloading-of-wasm	Change
_buildManifest.js gzip	484 B	483 B	N/A
Overall change	0 B	0 B	✓

Rendered Page Sizes

	vercel/next.js canary	d3lm/next.js delm/fix/downloading-of-wasm	Change
index.html gzip	529 B	526 B	N/A
link.html gzip	540 B	541 B	N/A
withRouter.html gzip	524 B	522 B	N/A
Overall change	0 B	0 B	✓

Edge SSR bundle Size

	vercel/next.js canary	d3lm/next.js delm/fix/downloading-of-wasm	Change
edge-ssr.js gzip	92.4 kB	92.4 kB	N/A
page.js gzip	145 kB	145 kB	N/A
Overall change	0 B	0 B	✓

Middleware size

	vercel/next.js canary	d3lm/next.js delm/fix/downloading-of-wasm	Change
middleware-b..fest.js gzip	626 B	624 B	N/A
middleware-r..fest.js gzip	150 B	151 B	N/A
middleware.js gzip	24.8 kB	24.8 kB	N/A
edge-runtime..pack.js gzip	1.92 kB	1.92 kB	✓
Overall change	1.92 kB	1.92 kB	✓

Next Runtimes

	vercel/next.js canary	d3lm/next.js delm/fix/downloading-of-wasm	Change
app-page-exp...dev.js gzip	167 kB	167 kB	✓
app-page-exp..prod.js gzip	93.4 kB	93.4 kB	✓
app-page-tur..prod.js gzip	94.1 kB	94.1 kB	✓
app-page-tur..prod.js gzip	88.7 kB	88.7 kB	✓
app-page.run...dev.js gzip	137 kB	137 kB	✓
app-page.run..prod.js gzip	88 kB	88 kB	✓
app-route-ex...dev.js gzip	23.8 kB	23.8 kB	✓
app-route-ex..prod.js gzip	16.4 kB	16.4 kB	✓
app-route-tu..prod.js gzip	16.5 kB	16.5 kB	✓
app-route-tu..prod.js gzip	16 kB	16 kB	✓
app-route.ru...dev.js gzip	23.2 kB	23.2 kB	✓
app-route.ru..prod.js gzip	16 kB	16 kB	✓
pages-api-tu..prod.js gzip	9.37 kB	9.37 kB	✓
pages-api.ru...dev.js gzip	9.64 kB	9.64 kB	✓
pages-api.ru..prod.js gzip	9.37 kB	9.37 kB	✓
pages-turbo...prod.js gzip	21.8 kB	21.8 kB	✓
pages.runtim...dev.js gzip	22.5 kB	22.5 kB	✓
pages.runtim..prod.js gzip	21.8 kB	21.8 kB	✓
server.runti..prod.js gzip	49.1 kB	49.1 kB	✓
Overall change	924 kB	924 kB	✓

Commit: a114a39

[ijjk]

Tests Passed

[ForsakenHarmony]

LGTM

probably a better way to convert the streams with Writable.toWeb or Readable.fromWeb, but this should work and I don't think it matters