CLI auto-complete support

[hu55a1n1]

Crate

ibc-relayer-cli

Summary

Add auto-complete support using a rust crate (clap/gumdrop) that can automatically generate the completions file (see Clap::gen_completions()).

Acceptance Criteria

We should be able to achieve something like this ->

The hermes documentation and README.md should provide instructions for setting this up. Also, installers/packages should be updated to include and source the completions file.

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[rnbguy]

I ended up here because of this. 😄
https://github.com/informalsystems/ibc-rs/blob/09a4b114b7fd414547c539bc8d541470c30b8164/scripts/gm/bin/shell-support#L110

I can take a look at this. This can be done in the same way rustup completions (bash|fish|zsh).

Here is how Archlinux distributes shell completions for Rustup.

    # Generate completion files.
    mkdir -p "$pkgdir/usr/share/bash-completion/completions"
    "$pkgdir"/usr/bin/rustup completions bash > "$pkgdir/usr/share/bash-completion/completions/rustup"
    "$pkgdir"/usr/bin/rustup completions bash cargo > "$pkgdir/usr/share/bash-completion/completions/cargo"
    mkdir -p "$pkgdir/usr/share/fish/vendor_completions.d"
    "$pkgdir"/usr/bin/rustup completions fish > "$pkgdir/usr/share/fish/vendor_completions.d/rustup.fish"
    mkdir -p "$pkgdir/usr/share/zsh/site-functions"
    "$pkgdir"/usr/bin/rustup completions zsh > "$pkgdir/usr/share/zsh/site-functions/_rustup"
    "$pkgdir"/usr/bin/rustup completions zsh cargo > "$pkgdir/usr/share/zsh/site-functions/_cargo"

[mzabaluev]

This should be easy to do with clap 3.x.

[rnbguy]

clap_generate used to exist already, which is now deprecated in favor of clap_complete when clap 3.x reached stable.

My changes for Modelator are at informalsystems/modelator@0aa7d41.

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^{I feel clap should provide a shell-completion feature to do this automatically.}

[mzabaluev]

I think we need to approach this by way of #1752, when we can start using clap 3.0 stable.

[mzabaluev]

My changes for Modelator are at informalsystems/modelator@0aa7d41.

@rnbguy Any chance to get the rnbguy/rust/clap-v3 branch for modelator merged soon? I've used it in #1777 draft, let's see if MBTs pass.

[mzabaluev]

@rnbguy Any chance to get the rnbguy/rust/clap-v3 branch for modelator merged soon?

I was a bit out of date and I see how that informalsystems/modelator#163 has been merged. The question then turns into "when is the next release?"

[rnbguy]

I will do a patch release at the end of the day :)

[rnbguy]

modelator 0.4.2 is up 😃