Generate shell completions with clap during build

[davideGiovannini]

Auto-generate shell-completion files via clap #115

[sharkdp]

This looks great, thank you very much!

We should also ship these files with each release (see e.g. https://github.com/sharkdp/fd/blob/56b6389dac945df313ce54072fcc01b91211a76c/ci/before_deploy.bash#L41-L43)

[sharkdp]

I think we should use "2.32" to be consistent with the dependency above.

[sharkdp]

Can we use the same mechanism as in fd here:

let outdir = std::env::var_os("SHELL_COMPLETIONS_DIR").or(std::env::var_os("OUT_DIR"));

See sharkdp/fd#121

It would also require us to use fs::create_dir_all:
sharkdp/fd@3104729

[sharkdp]

We need to make sure that the target directory exists.

[sharkdp]

Also, it would be great to do this for Windows deployments as well (in the before_deploy.ps1 script). I think we don't need a subfolder in case of the Windows archive.

[davideGiovannini]

I'm not familiar with how it should work on Windows.

Should it be something like this ?

Copy-Item "$SRC_DIR\target\release\build\bat-*\out\_bat.ps1" '.\autocomplete'

[sharkdp]

I guess just

Copy-Item $SRC_DIR\target\release\build\bat-*\out\_bat.ps1 '.\'

[sharkdp]

Travis is currently failing due to some formatting issues. You can cargo +nightly install rustfmt-nightly and then run cargo fmt from the repository folder. I can also do this for you, if you want.

[davideGiovannini]

You can cargo +nightly install rustfmt-nightly and then run cargo fmt from the repository folder.

is this the same as running cargo fmt installed with rustup component add rustfmt-preview ?
It's changing the formatting of files that I did not change

        modified:   src/assets.rs
        modified:   src/diff.rs
        modified:   src/printer.rs

Do wildcards work inside quotes?

Uhm probably not.
I'm removing the quotes

[sharkdp]

Hm, I'm not sure, but there might very well be a change in the format between this and rustfmt-nightly (which we currently use to enforce the style guide). This is unfortunate, but apparently there will be a 1.0 release soon which should stabilize the format.

[sharkdp]

Thank you very much!!