Re: Bash completion for git aliases containing nested subcommands

On Mon, Oct 03, 2022 at 11:45:51AM +0000, Tim Jaacks wrote:

In general: no. Our Bash completion script is organized as one _git_cmd() function for each git supported command. If a command has subcommands, then its completion function looks for any of its subcommands amond the words on the command line, and takes the appropriate action, which is usually executing a particular arm of a case statement. The two main issues are that in case of such an alias there is no subcommand ("show") on the command line, and there is no dedicated function to handle only the completion for 'git stash show'.

However, it is possible to make completion work for your particular alias by using our completion script's extension mechanism that allows users to specify completion functions to their own git commands. If you type 'git foo <TAB>' and there is a _git_foo() function in your shell's environment, then the completion script will invoke that function to perform completion; this works not only for commands but for aliases as well. So for your alias you only need to "borrow" all the "show"-subcommand-specific case arms from _git_stash() and place them in a _git_ss() function, e.g. like this:

_git_ss () {
	case "$cur" in
	--*)
		__gitcomp_builtin stash_show "$__git_diff_common_options"
		;;
	*)
		__gitcomp_nl "$(__git stash list | sed -n -e 's/:.*//p')"
		;;
	esac
}

Add it to your ~/.bashrc, or to a separate file that you source from your .bashrc; If you use bash-completion, then you don't even have to touch you .bashrc: save that function to a file 'git-ss' (dash, not underscore!) in one of the directories scanned by bash-completion ($BASH_COMPLETION_USER_DIR, ~/.local/share/bash-completion/completions or its XDG_DATA_HOME-equivalent) and it will be auto-loaded as needed.

This approach should work just as well for any other similar "command subcommand" alias that you might have; with the downside that you'll have to write all these functions yourself.