Fix fail when upgrading incompatible optional dependencies

[katakonst]

Summary
This was caused by setting the optional field to false.This is fixed by searching if the optional dependency exists in manifest.

fixes #5471

[arcanis]

Hey @katakonst! Sorry for the delay - can you please add a test? I'll then merge it for the 1.13 release (scheduled in two weeks from now, I'd say).

[buildsize]

File name	Previous Size	New Size	Change
yarn-[version].noarch.rpm	1.1 MB	1.1 MB	-1.56 KB (0%)
yarn-[version].js	4.46 MB	4.46 MB	102 bytes (0%)
yarn-legacy-[version].js	4.65 MB	4.63 MB	-17.26 KB (0%)
yarn-v[version].tar.gz	1.11 MB	1.11 MB	-1.84 KB (0%)
yarn_[version]all.deb	813.46 KB	812.6 KB	-886 bytes (0%)

[katakonst]

Added a test!

[kristian]

Will likely also fix #6526. Could this one be merged w/ the next release? A review is still pending. Thanks.

[dylanmerrick]

Any chance this can go in? It's been sitting idle for a while...

[kristian]

@arcanis any update here? Still we cannot use / switch to Yarn 2, because we have the issue that some of our optional dependencies do not exist in some of our repositories, and we need the install to not fail (which atm. it still does).

Update: Sorry I just saw this is for Yarn 1. I will open the same issue in the berry repository.

[kristian]

I did create follow-up ticket: yarnpkg/berry#4306 in the https://github.com/yarnpkg/berry/ repository. Please let me know if I should suggest a PR to fix it.