Request: Support aliases in argcompletion

[jonasstoetzel]

Hi,

For my-awesome-script, we currently don't do any work to make this work with aliases. If you need this, I'd suggest opening a new issue to request the feature.

There it is! :-)
I currently have a script at /path/to/file which takes two positional arguments arg1 + arg2. The script is usually called via alias a=python3 /path/to/file arg1 and arg2 should be completable. It works fine when I type it out, but it would be really nice if I could use argcomplete with my alias.

Thanks!

[evanunderscore]

From my limited reading it seems this is a general problem with completion and not something we should deal with inside argcomplete. Here a few of the pages I've looked at:

• https://stackoverflow.com/questions/342969/how-do-i-get-bash-completion-to-work-with-aliases
• https://unix.stackexchange.com/questions/4219/how-do-i-get-bash-completion-for-command-aliases
• https://ubuntuforums.org/showthread.php?t=733397

[jonasstoetzel]

The suggestions for arg2 are computed inside of /path/to/file though and I don't know how to do that in bash (getting suggestions from a single file). It would be a lot easier if this could be done in argcomplete. Is there any chance this could be implemented? I'm sure lots of users would benefit from this feature if it existed.

[evanunderscore]

Looking at this a bit more closely, we would at least have to replace the alias in COMP_LINE for any generic solution to work, including in global completion where the above links don't apply. I don't have any time to work on this, but I'd be happy to help where I can if you want to work on a solution (provided @kislyuk is interested in merging this feature in some form).

[jonasstoetzel]

I'm afraid I don't know how to approach this. I managed to circumvent this issue by defining

• a function in .bashrc which calls /path/to/file and
• a wrapper in /etc/bash_completion.d/ inspired by "A Basic Example" from https://debian-administration.org/article/317/An_introduction_to_bash_completion_part_2

However, this does not work with aliases. The function defined in .bashrc acts speeds things up though.

[kislyuk]

I'm not sure if we want to accommodate aliases. In case we do, here is how the git bashcomp shellcode does it:

__git_complete ()
{
    local wrapper="__git_wrap${2}";
    eval "$wrapper () { __git_func_wrap $2 ; }";
    complete -o bashdefault -o default -o nospace -F $wrapper $1 2> /dev/null || complete -o default -o nospace -F $wrapper $1
}
__git_func_wrap ()
{
    local cur words cword prev;
    _get_comp_words_by_ref -n =: cur words cword prev;
    $1
}