t0060: verify that absolute_path() fails if passed the empty string

diff --git a/git-mergetool.sh b/git-mergetool.sh
index 085e213a126e5864befc8e3436832ae3c587a624..0db0c44845f54920e26d97391f577e76305ecc56 100755 (executable)
--- a/git-mergetool.sh
+++ b/git-mergetool.sh
@@ -8,7 +8,7 @@
 # at the discretion of Junio C Hamano.
 #
 
-USAGE='[--tool=tool] [-y|--no-prompt|--prompt] [file to merge] ...'
+USAGE='[--tool=tool] [--tool-help] [-y|--no-prompt|--prompt] [file to merge] ...'
 SUBDIRECTORY_OK=Yes
 OPTIONS_SPEC=
 TOOL_MODE=merge
@@ -181,10 +181,14 @@ stage_submodule () {
 }
 
 checkout_staged_file () {
-    tmpfile=$(expr "$(git checkout-index --temp --stage="$1" "$2")" : '\([^    ]*\)    ')
+    tmpfile=$(expr \
+           "$(git checkout-index --temp --stage="$1" "$2" 2>/dev/null)" \
+           : '\([^     ]*\)    ')
 
     if test $? -eq 0 -a -n "$tmpfile" ; then
        mv -- "$(git rev-parse --show-cdup)$tmpfile" "$3"
+    else
+       >"$3"
     fi
 }
 
@@ -224,9 +228,9 @@ merge_file () {
     mv -- "$MERGED" "$BACKUP"
     cp -- "$BACKUP" "$MERGED"
 
-    base_present   && checkout_staged_file 1 "$MERGED" "$BASE"
-    local_present  && checkout_staged_file 2 "$MERGED" "$LOCAL"
-    remote_present && checkout_staged_file 3 "$MERGED" "$REMOTE"
+    checkout_staged_file 1 "$MERGED" "$BASE"
+    checkout_staged_file 2 "$MERGED" "$LOCAL"
+    checkout_staged_file 3 "$MERGED" "$REMOTE"
 
     if test -z "$local_mode" -o -z "$remote_mode"; then
        echo "Deleted merge conflict for '$MERGED':"
@@ -280,11 +284,51 @@ merge_file () {
     return 0
 }
 
+show_tool_help () {
+       TOOL_MODE=merge
+       list_merge_tool_candidates
+       unavailable= available= LF='
+'
+       for i in $tools
+       do
+               merge_tool_path=$(translate_merge_tool_path "$i")
+               if type "$merge_tool_path" >/dev/null 2>&1
+               then
+                       available="$available$i$LF"
+               else
+                       unavailable="$unavailable$i$LF"
+               fi
+       done
+       if test -n "$available"
+       then
+               echo "'git mergetool --tool=<tool>' may be set to one of the following:"
+               echo "$available" | sort | sed -e 's/^/ /'
+       else
+               echo "No suitable tool for 'git mergetool --tool=<tool>' found."
+       fi
+       if test -n "$unavailable"
+       then
+               echo
+               echo 'The following tools are valid, but not currently available:'
+               echo "$unavailable" | sort | sed -e 's/^/       /'
+       fi
+       if test -n "$unavailable$available"
+       then
+               echo
+               echo "Some of the tools listed above only work in a windowed"
+               echo "environment. If run in a terminal-only session, they will fail."
+       fi
+       exit 0
+}
+
 prompt=$(git config --bool mergetool.prompt || echo true)
 
 while test $# != 0
 do
     case "$1" in
+       --tool-help)
+               show_tool_help
+               ;;
        -t|--tool*)
            case "$#,$1" in
                *,*=*)