Improve clippy --version output

[phansch]

Currently, running cargo clippy --version just returns 0.0.212. For debugging Clippy properly, we now need to know the exact commit that was included in rust nightly.

It would be nice to bring this in line with other components like cargo:

cargo 1.29.0-nightly (b42488270 2018-08-04)

The implementation from cargo is here

[matthiaskrgr]

I'll give this a try :)

[matthiaskrgr]

It seems that some of the env vars like CFG_RELEASE_CHANNEL and CFG_COMMIT_DATE are set by the rustc bootstrap program.

This means that when using these we can get commit hash info for the clippy shipped by rustup but when building locally, these information won't be available unless I start calling git "manually" and try to extract current repo hash etc...
Is this ok?

[matthiaskrgr]

calling git "manually" and try to extract current repo hash etc

RLS is taking this approach:

https://github.com/rust-lang-nursery/rls/blob/b6cdf4af930ee495a010bd3ade9460d3bbf0bd52/src/main.rs#L104

https://github.com/rust-lang-nursery/rls/blob/master/build.rs#L29-L63

[oli-obk]

Yea, I think replicating what rls does is ok, although we should probably move it into a crate that both clippy and rls use. Maybe something like rustc-tools-util where we can also add other stuff that they share.

[matthiaskrgr]

There seem to already be dedicated crates to do this, I'll have a look :)
https://crates.io/search?q=git%20version

[matthiaskrgr]

Ok, it turns out, when I put everything into an extra crate and query for env!("CARGO_PKG_VERSION_MAJOR"), we will get the version of rustc-tools-util crate and not of clippy xD

I guess the easiest fix is to actually move the code into the root repo...?

current progress: matthiaskrgr@01528b7

[oli-obk]

does it work if you make the VersionInfo::new function a macro? Will the other macros get expanded in the using crate?

[matthiaskrgr]

I tried that, it works for the clippy version but not for the git commands to find out the commit hash. These need to be executed in build.rs so we can bake an actual string inside clippy, as soon as we call "git" at runtime, we lost and get false information depending what CWD we are in.

[oli-obk]

Oh, now I understand. Running in build.rs is fine! I just meant to have the code to be run centralized in a crate that can be reused