Re: [PATCH] completion: avoid config variable name lookup error in nounset mode

[Junio C Hamano <gitster@pobox.com>]

Ville Skyttä <ville.skytta@iki.fi> writes:

> Config variable name lookup accesses the `sfx` variable before it has

The above sounds as if the function always makes an access to an
uninitialized variable, which puzzled me.  The problem exists only
when called from some callers that do not use the --sfx=X option,
which may be worth mentioning.

I see that, ever since the helper function was introduced at e1e00089
(completion: complete configuration sections and variable names for
'git -c', 2019-08-13), it would have upset 'set -u' when the caller
does not pass --sfx=X option, and even in that original version,
there was such a caller (the original author Cc'ed).

And the fix looks trivially correct.

I'll be busy preparing the -rc2 today, and will not be queuing this
patch right now, though.  As this is not a recent regression, waiting
for the current release cycle to be over and sending a reroll later
next week would be greatly appreciated.

Thanks.

> been set, causing an error in "nounset" mode. Initialize to an empty
> string to avoid that.
>
>     $ git config submodule.<Tab>bash: sfx: unbound variable
>
> Signed-off-by: Ville Skyttä <ville.skytta@iki.fi>
> ---
>  contrib/completion/git-completion.bash | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
> index 4bdd27ddc8..ecc9352755 100644
> --- a/contrib/completion/git-completion.bash
> +++ b/contrib/completion/git-completion.bash
> @@ -2631,7 +2631,7 @@ __git_complete_config_variable_value ()
>  #                 subsections) instead of the default space.
>  __git_complete_config_variable_name ()
>  {
> -	local cur_="$cur" sfx
> +	local cur_="$cur" sfx=""
>  
>  	while test $# != 0; do
>  		case "$1" in