bash-completion: Support running when set -u is enabled

Under "set -u" semantics, it is an error to access undefined variables.
Some user environments may enable this setting in the interactive shell.

In any context where the completion functions access an undefined
variable, accessing a default empty string (aka "${1-}" instead of "$1")
is a reasonable way to code the function, as it silences the undefined
variable error while still supplying an empty string.

In this patch, functions that should always take an argument still use
$1. Functions that have optional arguments use ${1-}.

Signed-off-by: Ted Pavlic <ted@tedpavlic.com>
Acked-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
index 7b074d79854813ffa38f781218bd878a79cbb505..5d1515cec4758c122c8838718d24ed72ae43b321 100755 (executable)
--- a/contrib/completion/git-completion.bash
+++ b/contrib/completion/git-completion.bash
@@ -52,7 +52,7 @@ esac
 
 __gitdir ()
 {
-       if [ -z "$1" ]; then
+       if [ -z "${1-}" ]; then
                if [ -n "$__git_dir" ]; then
                        echo "$__git_dir"
                elif [ -d .git ]; then
@@ -111,7 +111,7 @@ __git_ps1 ()
                        fi
                fi
 
-               if [ -n "$1" ]; then
+               if [ -n "${1-}" ]; then
                        printf "$1" "${b##refs/heads/}$r"
                else
                        printf " (%s)" "${b##refs/heads/}$r"
@@ -143,8 +143,8 @@ __gitcomp ()
                ;;
        *)
                local IFS=$'\n'
-               COMPREPLY=($(compgen -P "$2" \
-                       -W "$(__gitcomp_1 "$1" "$4")" \
+               COMPREPLY=($(compgen -P "${2-}" \
+                       -W "$(__gitcomp_1 "${1-}" "${4-}")" \
                        -- "$cur"))
                ;;
        esac
@@ -152,13 +152,13 @@ __gitcomp ()
 
 __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 ;;
@@ -170,13 +170,13 @@ __git_heads ()
 
 __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 ;;
@@ -188,7 +188,7 @@ __git_tags ()
 
 __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