git-completion.bash: use __gitcomp_builtin() in _git_stash()

The completion for 'git stash' has not changed in a major way since it
was converted from shell script to builtin. Now that it's a builtin, we
can take advantage of the groundwork laid out by parse-options and use
the generated options.

Rewrite _git_stash() to take use __gitcomp_builtin() to generate
completions for subcommands.

The main `git stash` command does not take any arguments directly. If no
subcommand is given, it automatically defaults to `git stash push`. This
means that we can simplify the logic for when no subcommands have been
given yet. We only have to offer subcommand completions when we're
completing a non-option after "stash".

One area that this patch could improve upon is that the `git stash list`
command accepts log-options. It would be nice if the completion for this
were unified with that of _git_log() and _git_show() which would allow
completions to be provided for options such as `--pretty` but that is
outside the scope of this patch.

Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

contrib/completion/git-completion.bash

@@ -3013,26 +3013,19 @@ _git_sparse_checkout ()
 
 _git_stash ()
 {
-	local save_opts='--all --keep-index --no-keep-index --quiet --patch --include-untracked'
 	local subcommands='push list show apply clear drop pop create branch'
 	local subcommand="$(__git_find_on_cmdline "$subcommands save")"
-	if [ -z "$subcommand" -a -n "$(__git_find_on_cmdline "-p")" ]; then
+
-		subcommand="push"
-	fi
 	if [ -z "$subcommand" ]; then
-		case "$cur" in
+		case "$((cword - __git_subcommand_idx)),$cur" in
-		--*)
+		*,--*)
-			__gitcomp "$save_opts"
+			__gitcomp_builtin stash_push
 			;;
-		sa*)
+		1,sa*)
-			if [ -z "$(__git_find_on_cmdline "$save_opts")" ]; then
+			__gitcomp "save"
-				__gitcomp "save"
-			fi
 			;;
-		*)
+		1,*)
-			if [ -z "$(__git_find_on_cmdline "$save_opts")" ]; then
+			__gitcomp "$subcommands"
-				__gitcomp "$subcommands"
-			fi
 			;;
 		esac
 		return
@@ -3040,24 +3033,29 @@ _git_stash ()
 
 	case "$subcommand,$cur" in
 	push,--*)
-		__gitcomp "$save_opts --message"
+		__gitcomp_builtin stash_push
 		;;
 	save,--*)
-		__gitcomp "$save_opts"
+		__gitcomp_builtin stash_save
 		;;
-	apply,--*|pop,--*)
+	pop,--*)
-		__gitcomp "--index --quiet"
+		__gitcomp_builtin stash_pop
+		;;
+	apply,--*)
+		__gitcomp_builtin stash_apply
 		;;
 	drop,--*)
-		__gitcomp "--quiet"
+		__gitcomp_builtin stash_drop
 		;;
 	list,--*)
-		__gitcomp "--name-status --oneline --patch-with-stat"
+		# NEEDSWORK: can we somehow unify this with the options in _git_log() and _git_show()
+		__gitcomp_builtin stash_list "$__git_log_common_options $__git_diff_common_options"
 		;;
 	show,--*)
-		__gitcomp "$__git_diff_common_options"
+		__gitcomp_builtin stash_show "$__git_diff_common_options"
 		;;
 	branch,--*)
+		__gitcomp_builtin stash_branch
 		;;
 	branch,*)
 		if [ $cword -eq $((__git_subcommand_idx+2)) ]; then