fix(compiler-sfc): error generating CSS sourcemap when using SCSS

[MuTsunTsai]

This is an attempt to fix #9969. See the issue for details.

[yyx990803]

Looks like I unintentionally introduced this regression in f15d2f6

If this is in fact a Buffer, we should probably just revert the change to always do JSON.parse(result.map.toString()).

[github-actions]

Size Report

Bundles

File	Size	Gzip	Brotli
runtime-dom.global.prod.js	89.5 kB	34 kB	30.7 kB
vue.global.prod.js	146 kB	53.3 kB	47.6 kB

Usages

Name	Size	Gzip	Brotli
createApp	49.8 kB	19.5 kB	17.8 kB
createSSRApp	53.1 kB	20.8 kB	19 kB
defineCustomElement	52.1 kB	20.3 kB	18.5 kB
overall	63.3 kB	24.4 kB	22.3 kB

[yyx990803]

Thanks for the PR - for some reason it seems to be including commits that shouldn't belong (maybe because the PR was based off main).

I've reverted SCSS source map handling to the old behavior in 71d3121.

[MuTsunTsai]

Thanks for the PR - for some reason it seems to be including commits that shouldn't belong (maybe because the PR was based off main).

Glad that the issue is resolved. Should I contribute anything else in the future, from which branch should I fork instead?

[yyx990803]

It's best to check out a new branch in your fork and work in that branch, so you can sync your main branch periodically with the upstream.