[PATCH] completion: bash: fix late declaration of __git_cmd_idx

A recent update to contrib/completion/git-completion.bash causes bash to fail
auto complete custom commands that are wrapped with __git_func_wrap. Declaring
__git_cmd_idx=0 inside __git_func_wrap resolves the issue.

Signed-off-by: Fabian Wermelinger <redacted>
---
Fixes `bash: [: -lt: unary operator expected` error for tab completions
of wrapped `git` commands.  For example, assume the convenience command
`gaa` defined in a shell script as

git aa "$@"

where `git aa` is an alias to `git add --all`.  Then `gaa` is wrapped
for bash completion like

__git_complete gaa _git_add

For this example, the current bash completion fails at
`contrib/completion/git-completion.bash:1190` due to empty local
variable `c` as `__git_cmd_idx` is empty at the definition in
`contrib/completion/git-completion.bash:1179`.  Defining
`__git_cmd_idx=0` earlier in `__git_func_wrap` attempts to solve this
problem.

 contrib/completion/git-completion.bash | 1 +
 1 file changed, 1 insertion(+)

diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
index b50c5d0ea3..ca5b456173 100644
--- a/contrib/completion/git-completion.bash
+++ b/contrib/completion/git-completion.bash

@@ -3512,6 +3512,7 @@ fi
 __git_func_wrap ()
 {
 	local cur words cword prev
+	local __git_cmd_idx=0
 	_get_comp_words_by_ref -n =: cur words cword prev
 	$1
 }

-- 
2.32.0

Fabian Wermelinger wrote:

A recent update to contrib/completion/git-completion.bash causes bash to fail
auto complete custom commands that are wrapped with __git_func_wrap. Declaring
__git_cmd_idx=0 inside __git_func_wrap resolves the issue.

I was about to say the idx should be 1, and that fixes the issue, but
actually 0 is more correct, since when we do __git_complete there's
actually no real command.

In the future we might want to improve __git_complete to manufacture a
real command since some completions do check the command at
__git_cmd_idx (e.g. __git_complete_remote_or_refspec), and then set
__git_cmd_idx to 1.

But for now your patch fixes the issue better than my previous patch
[1], however, it's still missing the zsh part. I've sent an update patch
with the best of both [2].

Cheers.

[1] https://lore.kernel.org/git/20210618182518.697912-2-felipe.contreras@gmail.com/
[2] https://lore.kernel.org/git/20210618185832.700477-1-felipe.contreras@gmail.com/

Cheers.

-- 
Felipe Contreras