Install shell completions with cmake #34714

Please describe the feature you'd like to see added.

When building a package, I currently have the following code to include shell completions for the relevant components:

for tool in bitcoin bitcoin-tx bitcoin-util bitcoin-wallet bitcoin-chainstate libbitcoinkernel
do
  DESTDIR="$pkgdir" cmake --install build --component "$tool"

  # shell completions
  if [ -f "contrib/completions/bash/$tool.bash" ]; then
    install -Dm644 "contrib/completions/bash/$tool.bash" \
      "$pkgdir/usr/share/bash-completion/completions/$tool"
  fi
  if [ -f "contrib/completions/fish/$tool.fish" ]; then
    install -Dm644 contrib/completions/fish/$tool.fish \
      -t "$pkgdir/usr/share/fish/vendor_completions.d/"
  fi
done

Is your feature related to a problem, if so please describe it.

No response

Describe the solution you'd like

I'm wondering if there could be a way to include the shell completions in cmake --install, so running DESTDIR="$pkgdir" cmake --install build --component bitcoin-tx would copy shell completions to DESTDIR, if any are available.

Describe any alternatives you've considered

Keeping the current code as-is. :)

Please leave any additional context

No response

cc @purpleKarrot

Thank you for your work packaging bitcoind on Arch @kpcyrd :)

IMO this seems like a perfectly reasonable request. I'd be happy to fix it.

I'll wait to see what @purpleKarrot thinks first, but the change itself is simple.

Go for it @willcl-ark! I agree that shell completions should be installed together with each tool.

We may want to rethink the 1:1 relationship of tool and component. Usually, you have components like "runtime", "development", and "data" where "runtime" contains binaries and .so files, "development" contains headers and soname links, "data" contains documentation, config files, shell completions, etc (all architecture independent files).

Packagers may then decide how to organize components into sub-packages. Arch usually packages everything together, other distros provide packages on a finer granularity.

We should make sure that @kpcyrd can execute:

cmake --install build --prefix $pkgdir

And that should install all files to their expected location.

I use Arch btw

Opened #34721 to address this.