Re: [PATCH v2 2/2] sparse-checkout: custom tab completion

[Elijah Newren <newren@gmail.com>]

On Fri, Dec 31, 2021 at 2:33 AM Lessley Dennington via GitGitGadget
<gitgitgadget@gmail.com> 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 | 38 ++++++++++++++++++--------
>  t/t9902-completion.sh                  |  8 +++---
>  2 files changed, 30 insertions(+), 16 deletions(-)
>
> diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
> index c82ccaebcc7..7de997ee64e 100644
> --- a/contrib/completion/git-completion.bash
> +++ b/contrib/completion/git-completion.bash
> @@ -2986,24 +2986,38 @@ _git_show_branch ()
>         __git_complete_revlist
>  }
>
> +__git_sparse_checkout_subcommand_opts="--cone --no-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
>         fi
>
> -       case "$subcommand,$cur" in
> -       init,--*)
> -               __gitcomp "--cone"
> -               ;;
> -       set,--*)
> -               __gitcomp "--stdin"
> -               ;;
> -       *)
> -               ;;
> +       case "$prev" in

Shouldn't this be "$subcommand" rather than "$prev"?  I think with
prev, it will only correctly complete the first path after "set",
"add", etc.

> +               set)
> +                       __gitcomp "$__git_sparse_checkout_subcommand_opts --stdin"
> +                       __gitcomp "$(git ls-tree -d -r HEAD --name-only)"
> +                       ;;
> +               add)
> +                       __gitcomp "--stdin"
> +                       __gitcomp "$(git ls-tree -d -r HEAD --name-only)"

I was going to make a simple suggestion for making it just complete
one additional level at a time and leaving out the -r, and then tried
it out and found out it wasn't simple.  I got something working,
eventually, but it's slightly ugly...so it probably belongs in a
separate patch anyway.  If you're curious, it's basically replacing
the second __gitcomp... call for each of set and add with
`__gitcomp_directories`, after first defining:

__gitcomp_directories ()
{
    local _tmp_dir _tmp_completions

    # Get the directory of the current token; this differs from dirname
    # in that it keeps up to the final trailing slash.  If no slash found
    # that's fine too.
    [[ "$cur" =~ .*/ ]]
    _tmp_dir=$BASH_REMATCH

    # Find possible directory completions, adding trailing '/' characters
    _tmp_completions="$(git ls-tree -d --name-only HEAD $_tmp_dir |
        sed -e s%$%/%)"

    if [[ -n "$_tmp_completions" ]]; then
        # There were some directory completions, so find ones that
        # start with "$cur", the current token, and put those in COMPREPLY
        local i=0 c IFS=$' \t\n'
        for c in $_tmp_completions; do
            if [[ $c == "$cur"* ]]; then
                COMPREPLY+=("$c")
            fi
        done
    elif [[ "$cur" =~ /$ ]]; then
        # No possible further completions any deeper, so assume we're at
        # a leaf directory and just consider it complete
        __gitcomp_direct_append "$cur "
    fi
}

But I don't think that needs to be part of this series; I can submit
it later and hopefully get a completion expert to point out
better/cleaner ways of what I've done above.

> +                       ;;
> +               init|reapply)
> +                       __gitcomp "$__git_sparse_checkout_subcommand_opts"
> +                       ;;
> +               *)
> +                       ;;
>         esac
>  }
>
> diff --git a/t/t9902-completion.sh b/t/t9902-completion.sh
> index 51d0f2d93a1..4dc93ee0595 100755
> --- a/t/t9902-completion.sh
> +++ b/t/t9902-completion.sh
> @@ -1447,7 +1447,7 @@ test_expect_success 'git checkout - with --detach, complete only references' '
>         EOF
>  '
>
> -test_expect_failure 'sparse-checkout completes subcommands' '
> +test_expect_success 'sparse-checkout completes subcommands' '
>         test_completion "git sparse-checkout " <<-\EOF
>         list Z
>         init Z
> @@ -1458,13 +1458,13 @@ test_expect_failure 'sparse-checkout completes subcommands' '
>         EOF
>  '
>
> -test_expect_failure 'sparse-checkout completes options' '
> +test_expect_success 'sparse-checkout completes options' '
>         test_completion "git sparse-checkout --" <<-\EOF
>         --help Z
>         EOF
>  '
>
> -test_expect_failure 'sparse-checkout completes subcommand options' '
> +test_expect_success 'sparse-checkout completes subcommand options' '
>         test_completion "git sparse-checkout init --" <<-\EOF &&
>         --cone Z
>         --no-cone Z
> @@ -1492,7 +1492,7 @@ test_expect_failure 'sparse-checkout completes subcommand options' '
>         EOF
>  '
>
> -test_expect_failure 'sparse-checkout completes directory names' '
> +test_expect_success 'sparse-checkout completes directory names' '
>         # set up sparse-checkout repo
>         git init sparse-checkout &&
>         (
> --
> gitgitgadget

Patch looks good to me, other than the $prev vs. $subcommand thing.