mergetool: use path to mergetool in config var mergetool.<tool>.path

This commit adds a mechanism to provide absolute paths to the
external programs called by 'git mergetool'. A path can be
specified in the configuation variable mergetool.<tool>.path.
The configuration variable is similar to how we name branches
and remotes. It is extensible if we need to specify more details
about a tool.

The mechanism is especially useful on Windows, where external
programs are unlikely to be in PATH.

[sp: Fixed a few minor issues prior to applying]

Signed-off-by: Steffen Prohaska <prohaska@zib.de>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

diff --git a/Documentation/git-mergetool.txt b/Documentation/git-mergetool.txt
index 6c32c6d..78b2f43 100644 (file)
--- a/Documentation/git-mergetool.txt
+++ b/Documentation/git-mergetool.txt
@@ -31,6 +31,12 @@ If a merge resolution program is not specified, 'git mergetool'
 will use the configuration variable merge.tool.  If the
 configuration variable merge.tool is not set, 'git mergetool'
 will pick a suitable default.
++
+You can explicitly provide a full path to the tool by setting the
+configuration variable mergetool.<tool>.path. For example, you
+can configure the absolute path to kdiff3 by setting
+mergetool.kdiff3.path. Otherwise, 'git mergetool' assumes the tool
+is available in PATH.
 
 Author
 ------

diff --git a/git-mergetool.sh b/git-mergetool.sh
index 9f4f313..4f89cbe 100755 (executable)
--- a/git-mergetool.sh
+++ b/git-mergetool.sh
@@ -192,10 +192,10 @@ merge_file () {
     case "$merge_tool" in
        kdiff3)
            if base_present ; then
-               (kdiff3 --auto --L1 "$path (Base)" --L2 "$path (Local)" --L3 "$path (Remote)" \
+               ("$merge_tool_path" --auto --L1 "$path (Base)" --L2 "$path (Local)" --L3 "$path (Remote)" \
                    -o "$path" -- "$BASE" "$LOCAL" "$REMOTE" > /dev/null 2>&1)
            else
-               (kdiff3 --auto --L1 "$path (Local)" --L2 "$path (Remote)" \
+               ("$merge_tool_path" --auto --L1 "$path (Local)" --L2 "$path (Remote)" \
                    -o "$path" -- "$LOCAL" "$REMOTE" > /dev/null 2>&1)
            fi
            status=$?
@@ -203,35 +203,35 @@ merge_file () {
            ;;
        tkdiff)
            if base_present ; then
-               tkdiff -a "$BASE" -o "$path" -- "$LOCAL" "$REMOTE"
+               "$merge_tool_path" -a "$BASE" -o "$path" -- "$LOCAL" "$REMOTE"
            else
-               tkdiff -o "$path" -- "$LOCAL" "$REMOTE"
+               "$merge_tool_path" -o "$path" -- "$LOCAL" "$REMOTE"
            fi
            status=$?
            save_backup
            ;;
        meld|vimdiff)
            touch "$BACKUP"
-           $merge_tool -- "$LOCAL" "$path" "$REMOTE"
+           "$merge_tool_path" -- "$LOCAL" "$path" "$REMOTE"
            check_unchanged
            save_backup
            ;;
        gvimdiff)
                touch "$BACKUP"
-               gvimdiff -f -- "$LOCAL" "$path" "$REMOTE"
+               "$merge_tool_path" -f -- "$LOCAL" "$path" "$REMOTE"
                check_unchanged
                save_backup
                ;;
        xxdiff)
            touch "$BACKUP"
            if base_present ; then
-               xxdiff -X --show-merged-pane \
+               "$merge_tool_path" -X --show-merged-pane \
                    -R 'Accel.SaveAsMerged: "Ctrl-S"' \
                    -R 'Accel.Search: "Ctrl+F"' \
                    -R 'Accel.SearchForward: "Ctrl-G"' \
                    --merged-file "$path" -- "$LOCAL" "$BASE" "$REMOTE"
            else
-               xxdiff -X --show-merged-pane \
+               "$merge_tool_path" -X --show-merged-pane \
                    -R 'Accel.SaveAsMerged: "Ctrl-S"' \
                    -R 'Accel.Search: "Ctrl+F"' \
                    -R 'Accel.SearchForward: "Ctrl-G"' \
@@ -243,18 +243,18 @@ merge_file () {
        opendiff)
            touch "$BACKUP"
            if base_present; then
-               opendiff "$LOCAL" "$REMOTE" -ancestor "$BASE" -merge "$path" | cat
+               "$merge_tool_path" "$LOCAL" "$REMOTE" -ancestor "$BASE" -merge "$path" | cat
            else
-               opendiff "$LOCAL" "$REMOTE" -merge "$path" | cat
+               "$merge_tool_path" "$LOCAL" "$REMOTE" -merge "$path" | cat
            fi
            check_unchanged
            save_backup
            ;;
        emerge)
            if base_present ; then
-               emacs -f emerge-files-with-ancestor-command "$LOCAL" "$REMOTE" "$BASE" "$(basename "$path")"
+               "$merge_tool_path" -f emerge-files-with-ancestor-command "$LOCAL" "$REMOTE" "$BASE" "$(basename "$path")"
            else
-               emacs -f emerge-files-command "$LOCAL" "$REMOTE" "$(basename "$path")"
+               "$merge_tool_path" -f emerge-files-command "$LOCAL" "$REMOTE" "$(basename "$path")"
            fi
            status=$?
            save_backup
@@ -297,17 +297,38 @@ do
     shift
 done
 
+valid_tool() {
+       case "$1" in
+               kdiff3 | tkdiff | xxdiff | meld | opendiff | emerge | vimdiff | gvimdiff)
+                       ;; # happy
+               *)
+                       return 1
+                       ;;
+       esac
+}
+
+init_merge_tool_path() {
+       merge_tool_path=`git config mergetool.$1.path`
+       if test -z "$merge_tool_path" ; then
+               case "$1" in
+                       emerge)
+                               merge_tool_path=emacs
+                               ;;
+                       *)
+                               merge_tool_path=$1
+                               ;;
+               esac
+       fi
+}
+
+
 if test -z "$merge_tool"; then
     merge_tool=`git config merge.tool`
-    case "$merge_tool" in
-       kdiff3 | tkdiff | xxdiff | meld | opendiff | emerge | vimdiff | gvimdiff | "")
-           ;; # happy
-       *)
+    if ! valid_tool "$merge_tool"; then
            echo >&2 "git config option merge.tool set to unknown tool: $merge_tool"
            echo >&2 "Resetting to default..."
            unset merge_tool
-           ;;
-    esac
+    fi
 fi
 
 if test -z "$merge_tool" ; then
@@ -329,40 +350,30 @@ if test -z "$merge_tool" ; then
     merge_tool_candidates="$merge_tool_candidates opendiff emerge vimdiff"
     echo "merge tool candidates: $merge_tool_candidates"
     for i in $merge_tool_candidates; do
-        if test $i = emerge ; then
-            cmd=emacs
-        else
-            cmd=$i
-        fi
-        if type $cmd > /dev/null 2>&1; then
+        init_merge_tool_path $i
+        if type "$merge_tool_path" > /dev/null 2>&1; then
             merge_tool=$i
             break
         fi
     done
     if test -z "$merge_tool" ; then
-       echo "No available merge resolution programs available."
+       echo "No known merge resolution program available."
        exit 1
     fi
+else
+    if ! valid_tool "$merge_tool"; then
+        echo >&2 "Unknown merge_tool $merge_tool"
+        exit 1
+    fi
+
+    init_merge_tool_path "$merge_tool"
+
+    if ! type "$merge_tool_path" > /dev/null 2>&1; then
+        echo "The merge tool $merge_tool is not available as '$merge_tool_path'"
+        exit 1
+    fi
 fi
 
-case "$merge_tool" in
-    kdiff3|tkdiff|meld|xxdiff|vimdiff|gvimdiff|opendiff)
-       if ! type "$merge_tool" > /dev/null 2>&1; then
-           echo "The merge tool $merge_tool is not available"
-           exit 1
-       fi
-       ;;
-    emerge)
-       if ! type "emacs" > /dev/null 2>&1; then
-           echo "Emacs is not available"
-           exit 1
-       fi
-       ;;
-    *)
-       echo "Unknown merge tool: $merge_tool"
-       exit 1
-       ;;
-esac
 
 if test $# -eq 0 ; then
        files=`git ls-files -u | sed -e 's/^[^  ]*      //' | sort -u`