Simplest update to bash completions to prevent unbounded variable errors

index 7b074d7..323829e 100755
@@ -1,3 +1,4 @@
+#!bash
 #
 # bash completion support for core Git.
 #

@@ -50,9 +51,11 @@ case "$COMP_WORDBREAKS" in
 *)   COMP_WORDBREAKS="$COMP_WORDBREAKS:"
 esac
 
+# __gitdir accepts 0 or 1 arguments (i.e., location)
+# returns location of .git repo
 __gitdir ()
 {
-	if [ -z "$1" ]; then
+	if [ $# -eq 0 ] || [ -z "$1" ]; then
 		if [ -n "$__git_dir" ]; then
 			echo "$__git_dir"
 		elif [ -d .git ]; then

@@ -67,6 +70,8 @@ __gitdir ()
 	fi
 }
 
+# __git_ps1 accepts 0 or 1 arguments (i.e., format string)
+# returns text to add to bash PS1 prompt (includes branch name)
 __git_ps1 ()
 {
 	local g="$(git rev-parse --git-dir 2>/dev/null)"

@@ -111,7 +116,7 @@ __git_ps1 ()
 			fi
 		fi
 
-		if [ -n "$1" ]; then
+		if [ $# -gt 0 ] && [ -n "$1" ]; then
 			printf "$1" "${b##refs/heads/}$r"
 		else
 			printf " (%s)" "${b##refs/heads/}$r"

@@ -119,6 +124,7 @@ __git_ps1 ()
 	fi
 }
 
+# __gitcomp_1 requires 2 arguments
 __gitcomp_1 ()
 {
 	local c IFS=' '$'\t'$'\n'

@@ -131,6 +137,8 @@ __gitcomp_1 ()
 	done
 }
 
+# __gitcomp accepts 1, 2, 3, or 4 arguments
+# generates completion reply with compgen
 __gitcomp ()
 {
 	local cur="${COMP_WORDS[COMP_CWORD]}"

@@ -143,22 +151,23 @@ __gitcomp ()
 		;;
 	*)
 		local IFS=$'\n'
-		COMPREPLY=($(compgen -P "$2" \
-			-W "$(__gitcomp_1 "$1" "$4")" \
+		COMPREPLY=($(compgen -P "${2-}" \
+			-W "$(__gitcomp_1 "${1-}" "${4-}")" \
 			-- "$cur"))
 		;;
 	esac
 }
 
+# __git_heads accepts 0 or 1 arguments (to pass to __gitdir)
 __git_heads ()
 {
-	local cmd i is_hash=y dir="$(__gitdir "$1")"
+	local cmd i is_hash=y dir="$(__gitdir "${1-}")"
 	if [ -d "$dir" ]; then
 		git --git-dir="$dir" for-each-ref --format='%(refname:short)' \
 			refs/heads
 		return
 	fi
-	for i in $(git ls-remote "$1" 2>/dev/null); do
+	for i in $(git ls-remote "${1-}" 2>/dev/null); do
 		case "$is_hash,$i" in
 		y,*) is_hash=n ;;
 		n,*^{}) is_hash=y ;;

@@ -168,15 +177,16 @@ __git_heads ()
 	done
 }
 
+# __git_tags accepts 0 or 1 arguments (to pass to __gitdir)
 __git_tags ()
 {
-	local cmd i is_hash=y dir="$(__gitdir "$1")"
+	local cmd i is_hash=y dir="$(__gitdir "${1-}")"
 	if [ -d "$dir" ]; then
 		git --git-dir="$dir" for-each-ref --format='%(refname:short)' \
 			refs/tags
 		return
 	fi
-	for i in $(git ls-remote "$1" 2>/dev/null); do
+	for i in $(git ls-remote "${1-}" 2>/dev/null); do
 		case "$is_hash,$i" in
 		y,*) is_hash=n ;;
 		n,*^{}) is_hash=y ;;

@@ -186,9 +196,10 @@ __git_tags ()
 	done
 }
 
+# __git_refs accepts 0 or 1 arguments (to pass to __gitdir)
 __git_refs ()
 {
-	local i is_hash=y dir="$(__gitdir "$1")"
+	local i is_hash=y dir="$(__gitdir "${1-}")"
 	local cur="${COMP_WORDS[COMP_CWORD]}" format refs
 	if [ -d "$dir" ]; then
 		case "$cur" in

@@ -218,6 +229,7 @@ __git_refs ()
 	done
 }
 
+# __git_refs2 requires 1 argument (to pass to __git_refs)
 __git_refs2 ()
 {
 	local i

@@ -226,6 +238,7 @@ __git_refs2 ()
 	done
 }
 
+# __git_refs_remotes requires 1 argument (to pass to ls-remote)
 __git_refs_remotes ()
 {
 	local cmd i is_hash=y

@@ -470,6 +483,7 @@ __git_aliases ()
 	done
 }
 
+# __git_aliased_command requires 1 argument
 __git_aliased_command ()
 {
 	local word cmdline=$(git --git-dir="$(__gitdir)" \

@@ -482,6 +496,7 @@ __git_aliased_command ()
 	done
 }
 
+# __git_find_subcommand requires 1 argument
 __git_find_subcommand ()
 {
 	local word subcommand c=1

@@ -1766,13 +1781,16 @@ _gitk ()
 	__git_complete_revlist
 }
 
-complete -o default -o nospace -F _git git
-complete -o default -o nospace -F _gitk gitk
+complete -o bashdefault -o default -o nospace -F _git git 2>/dev/null \
+	|| complete -o default -o nospace -F _git git
+complete -o bashdefault -o default -o nospace -F _gitk gitk 2>/dev/null \
+	|| complete -o default -o nospace -F _gitk gitk
 
 # The following are necessary only for Cygwin, and only are needed
 # when the user has tab-completed the executable name and consequently
 # included the '.exe' suffix.
 #
 if [ Cygwin = "$(uname -o 2>/dev/null)" ]; then
-complete -o default -o nospace -F _git git.exe
+complete -o bashdefault -o default -o nospace -F _git git.exe 2>/dev/null \
+	|| complete -o default -o nospace -F _git git.exe
 fi