[revert 6193] Remove Compilation.libraries

[gnzlbg]

This PR reverts #6193 .

It appears that the only reason for the removal was that this API was unused, but as pointed out in the original PR, Rust projects are using this API.

No deprecation warning indicating the migration path was issued (there was a non-doc comment indicating that the API was deprecated, but that's it, no deprecation() attribute was used at all).

#6193 cites #5651 for the removal, but this comment there also states that there are projects using this API and therefore "I'm not sure if we should just leave it, remove it, or replace it with something better". No replacement is discussed anywhere in those PRs and AFAICT no such replacement is available.

Please, do a cargo release after this PR is merged.

cc @dwijnand

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[dwijnand]

I'm not sure if this is stated anywhere formal, but Cargo doesn't have a public API so depending on its programmatic API is at your own risk and without deprecation warnings. The CLI is what's stable.

I think the output of cargo metadata is intended for programmatic consumption, so you might want to look at that.

I don't think we should revert the removal.

[gnzlbg]

I don't think we should revert the removal.

I see! I'll explore whether it is possible to migrate rust-semverver to cargo metadata in the future, in my little experience with cargo metadata I doubt that it will be possible to do so easily.

For the people of the future, I've published a fork of cargo (https://github.com/gnzlbg/cargo/tree/cargo_semverver) with this patch under cargo-semverver on crates.io in case other projects need this functionality ! Sorry for the noise!

[gnzlbg]

I think the output of cargo metadata is intended for programmatic consumption, so you might want to look at that.

FWIW I explored using cargo metadata more in-depth today, but AFAICT the output of cargo metadata does not contain any information about the output paths of rlibs, for example (or any output paths of any build artifacts whatsoever).

So it appears that we are going to have to maintain our own fork of cargo for the forseable future.

[ehuss]

output paths of rlibs

The JSON output from cargo build is probably the best way to obtain this.