Re: [PATCH v2 3/5] completion: add and use __git_compute_first_level_config_vars_for_section

> From: Philippe Blain <levraiphilippeblain@gmail.com>
> 
> The function __git_complete_config_variable_name in the Bash completion
> script hardcodes several config variable names. These variables are
> those in config section where user-defined names can appear, such as
> "branch.<name>". These sections are treated first by the case statement,
> and the two last "catch all" cases are used for other sections, making
> use of the __git_compute_config_vars and __git_compute_config_sections
> function, which omit listing any variables containing wildcards or
> placeholders. Having hardcoded config variables introduces the risk of
> the completion code becoming out of sync with the actual config
> variables accepted by Git.
> 
> To avoid these hardcoded config variables, introduce a new function,
> __git_compute_first_level_config_vars_for_section, making use of the
> existing __git_config_vars variable. This function takes as argument a
> config section name and computes the matching "first level" config
> variables for that section, i.e. those _not_ containing any placeholder,
> like 'branch.autoSetupMerge, 'remote.pushDefault', etc.  Use this
> function and the variables it defines in the 'branch.*', 'remote.*' and
> 'submodule.*' switches of the case statement instead of hardcoding the
> corresponding config variables.  Note that we use indirect expansion
> instead of associative arrays because those are not supported in Bash 3,
> on which macOS is stuck for licensing reasons.
> 
> Add a test to make sure the new function works correctly by verfying it
> lists all 'submodule' config variables. This has the downside that this
> test must be updated when new 'submodule' configuration are added, but
> this should be a small burden since it happens infrequently.
> 
> Signed-off-by: Philippe Blain <levraiphilippeblain@gmail.com>
> ---
>  contrib/completion/git-completion.bash | 24 +++++++++++++++++++++---
>  t/t9902-completion.sh                  | 11 +++++++++++
>  2 files changed, 32 insertions(+), 3 deletions(-)
> 
> diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
> index 8af9bc3f4e1..2934ceb7637 100644
> --- a/contrib/completion/git-completion.bash
> +++ b/contrib/completion/git-completion.bash
> @@ -2596,6 +2596,15 @@ __git_compute_config_vars ()
>  	__git_config_vars="$(git help --config-for-completion)"
>  }
>  
> +__git_compute_first_level_config_vars_for_section ()
> +{
> +	section="$1"

> +	__git_compute_config_vars
> +	local this_section="__git_first_level_config_vars_for_section_${section}"
> +	test -n "${!this_section}" ||
> +	printf -v "__git_first_level_config_vars_for_section_${section}" %s "$(echo "$__git_config_vars" | grep -E "^${section}\.[a-z]" | awk -F. '{print $2}')"
> +}

>  __git_config_sections=
>  __git_compute_config_sections ()
>  {
> @@ -2749,8 +2758,11 @@ __git_complete_config_variable_name ()
>  	branch.*)
>  		local pfx="${cur_%.*}."
>  		cur_="${cur_#*.}"
> +		local section="${pfx%.}"
>  		__gitcomp_direct "$(__git_heads "$pfx" "$cur_" ".")"
> -		__gitcomp_nl_append $'autoSetupMerge\nautoSetupRebase\n' "$pfx" "$cur_" "${sfx:- }"
> +		__git_compute_first_level_config_vars_for_section "${section}"
> +		local this_section="__git_first_level_config_vars_for_section_${section}"
> +		__gitcomp_nl_append "${!this_section}" "$pfx" "$cur_" "${sfx:- }"
>  		return
>  		;;
>  	guitool.*.*)
> @@ -2799,8 +2811,11 @@ __git_complete_config_variable_name ()
>  	remote.*)
>  		local pfx="${cur_%.*}."
>  		cur_="${cur_#*.}"
> +		local section="${pfx%.}"
>  		__gitcomp_nl "$(__git_remotes)" "$pfx" "$cur_" "."
> -		__gitcomp_nl_append "pushDefault" "$pfx" "$cur_" "${sfx:- }"
> +		__git_compute_first_level_config_vars_for_section "${section}"
> +		local this_section="__git_first_level_config_vars_for_section_${section}"
> +		__gitcomp_nl_append "${!this_section}" "$pfx" "$cur_" "${sfx:- }"
>  		return
>  		;;
>  	submodule.*.*)
> @@ -2812,8 +2827,11 @@ __git_complete_config_variable_name ()
>  	submodule.*)
>  		local pfx="${cur_%.*}."
>  		cur_="${cur_#*.}"
> +		local section="${pfx%.}"
>  		__gitcomp_nl "$(__git config -f "$(__git rev-parse --show-toplevel)/.gitmodules" --get-regexp 'submodule.*.path' | awk -F. '{print $2}')" "$pfx" "$cur_" "."
> -		__gitcomp_nl_append $'alternateErrorStrategy\nfetchJobs\nactive\nalternateLocation\nrecurse\npropagateBranches' "$pfx" "$cur_" "${sfx:- }"
> +		__git_compute_first_level_config_vars_for_section "${section}"
> +		local this_section="__git_first_level_config_vars_for_section_${section}"
> +		__gitcomp_nl_append "${!this_section}" "$pfx" "$cur_" "${sfx:- }"
>  		return
>  		;;
>  	url.*.*)
> diff --git a/t/t9902-completion.sh b/t/t9902-completion.sh
> index 35eb534fdda..f28d8f531b7 100755
> --- a/t/t9902-completion.sh
> +++ b/t/t9902-completion.sh
> @@ -2583,6 +2583,17 @@ test_expect_success 'git config - variable name include' '
>  	EOF
>  '
>  
> +test_expect_success 'git config - variable name - __git_compute_first_level_config_vars_for_section' '
> +	test_completion "git config submodule." <<-\EOF
> +	submodule.active Z
> +	submodule.alternateErrorStrategy Z
> +	submodule.alternateLocation Z
> +	submodule.fetchJobs Z
> +	submodule.propagateBranches Z
> +	submodule.recurse Z
> +	EOF
> +'
> +

>  test_expect_success 'git config - value' '
>  	test_completion "git config color.pager " <<-\EOF
>  	false Z
> -- 
> gitgitgadget
> 
>