Re: [PATCH 2/2] sparse-checkout: custom tab completion

[Derrick Stolee <stolee@gmail.com>]

On 12/29/2021 7:32 PM, Lessley Dennington via GitGitGadget wrote:
> From: Lessley Dennington <lessleydennington@gmail.com>
> 
> Fix custom tab completion for sparse-checkout command. This will ensure:
> 
> 1. The full list of subcommands is provided when users enter git
> sparse-checkout <TAB>.
> 2. The --help option is tab-completable.
> 3. Subcommand options are tab-completable.
> 4. A list of directories (but not files) is provided when users enter git
> sparse-checkout add <TAB> or git sparse-checkout set <TAB>.
> 
> Failing tests that were added in the previous commit to verify these
> scenarios are now passing with these updates.
> 
> Signed-off-by: Lessley Dennington <lessleydennington@gmail.com>
> ---
>  contrib/completion/git-completion.bash | 34 +++++++++++++++++---------
>  t/t9902-completion.sh                  |  8 +++---
>  2 files changed, 26 insertions(+), 16 deletions(-)
> 
> diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
> index 377d6c5494a..b8f1caece83 100644
> --- a/contrib/completion/git-completion.bash
> +++ b/contrib/completion/git-completion.bash
> @@ -2986,24 +2986,34 @@ _git_show_branch ()
>  	__git_complete_revlist
>  }
>  
> +__git_sparse_checkout_init_opts="--cone --sparse-index --no-sparse-index"
> +
>  _git_sparse_checkout ()
>  {
> -	local subcommands="list init set disable"
> +	local subcommands="list init set disable add reapply"
>  	local subcommand="$(__git_find_on_cmdline "$subcommands")"
> +
>  	if [ -z "$subcommand" ]; then
> -		__gitcomp "$subcommands"
> -		return
> +		case "$cur" in
> +			--*)
> +				__gitcomp "--help"
> +				;;
> +			*)
> +				__gitcomp "$subcommands"
> +				;;
> +		esac

This part fixes the --<tab> completion. I suppose if someone
did "-<tab>" then nothing would show up?

>  	fi
>  
> -	case "$subcommand,$cur" in
> -	init,--*)
> -		__gitcomp "--cone"
> -		;;
> -	set,--*)
> -		__gitcomp "--stdin"
> -		;;
> -	*)
> -		;;
> +	case "$prev" in
> +		init)
> +			__gitcomp "$__git_sparse_checkout_init_opts"
> +			;;
> +		add|set)
> +			__gitcomp "--stdin"
> +			__gitcomp "$(git ls-tree -d -r HEAD --name-only)"> +			;;

With the thinking of rebasing onto en/sparse-checkout-set, this
could possibly be rearranged so the add|set) cases pass-through
into the init) and reapply) cases (skip the ;; between) to save
some duplication. Or, it is possible that doesn't work, but it
might be worth a try.

Also, since you are using 'git ls-tree' and not 'git ls-files',
the sparse index will not have an effect on the performance.
There will be some corner cases where a directory exists in one
of HEAD or the index but not the other. That's probably still
the right way to go since 'git ls-files' doesn't have a way to
only list directories. It just means that you probably don't
need to explicitly disable the sparse index in your test.

Thanks,
-Stolee