Branch autocompletion does not work with git alias for push

Question

I am using Git with git-completion and everything works fine with a single exception: when I do

git p some_remote [TAB]

I get as autocomplete suggestions the files in the current directory (wrong). p is a Git alias:

$ cat ~/.gitconfig
[alias]
    p = push

Still, when I do:

git push some_remote [TAB]

I get as suggestions the branches in the current repository (correct). In both cases the completion for some_remote works correctly.

What is the reason for this?

Answer 1

It's a bug!

git-completion.bash does go through your git aliases, wiring each up to the right completion function.

But then four of those—the functions for git push, fetch, pull, and remote—delegate to __git_complete_remote_or_refspec(), which starts like this:

__git_complete_remote_or_refspec ()
{
    local cur_="$cur" cmd="${words[1]}"
    ...

$words is just the list of tokens from the command line, and a few lines down, it starts checking $cmd without expanding aliases, for example:

case "$cmd" in
fetch)
  # ...
pull|remote)
  # ...

As far as I can tell, Gábor Szeder first reported this two years ago in a thread about making completion work with shell aliases.

He mentioned it again in 2012 in reply to a patch from Felipe Contreras (@felipec). Last month, Felipe announced his fork of git, which actually has a self-contained patch for this: b7b6be72.

I don't know if that's been submitted upstream, but in the meantime... if you want to test it out, apply the patch to your git-completion.bash:

curl https://github.com/felipec/git/commit/b7b6be72d60d.diff |
  patch -d [directory containing git-completion.bash]
  # useful options for patch: --verbose --dry-run

If you don't know where your current git-completion.bash lives, try declare -F:

dirname "$(shopt -s extdebug; declare -F __git_complete | awk '{ print $3 }')"

(After patching git-completion.bash, it'll prompt you for the location of git-completion.zsh to apply the second hunk... you can just hit ^C to skip it.)

Answer 2

Update April 2014, for Git 2.0:

The commit 880111c (Felipe Contreras (felipec)) now includes:

completion: fix completing args of aliased "push", "fetch", etc.

Some commands need the first word to determine the actual action that is being executed, however, the command is wrong when we use an alias, for example 'alias.p=push', if we try to complete 'git p origin <TAB>', the result would be wrong because __git_complete_remote_or_refspec() doesn't know where it came from.

So let's override words[1], so the alias 'p' is override by the actual command, 'push'.

---

git-completion doesn't seem to work well with git alias or regular alias.

For instance, if you had defined an alias 'gp' for 'git push', as in "How do I get bash completion to work with aliases?", you could type:

__git_complete gp _git_push

Maybe something similar exist for git aliases, as in this script.