[PATCH v4 3/3] git-mergetool--lib: Make vimdiff retain the current directory

[David Aguilar <davvid@gmail.com>]

When using difftool with vimdiff it can be unexpected that
the current directory changes to the root of the project.
Tell vim to chdir to the value of $GIT_PREFIX to fix this.

Care is taken to quote the variable so that vim expands it.
This avoids problems when directory names contain spaces.

Signed-off-by: David Aguilar <davvid@gmail.com>
Reported-by: Frédéric Heitzmann <frederic.heitzmann@gmail.com>
---
How embarassing.  I'm going to bed now.  This one works.

 git-mergetool--lib.sh |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/git-mergetool--lib.sh b/git-mergetool--lib.sh
index 4db9212..91f90ac 100644
--- a/git-mergetool--lib.sh
+++ b/git-mergetool--lib.sh
@@ -86,6 +86,11 @@ get_merge_tool_cmd () {
 }
 
 run_merge_tool () {
+	# If GIT_PREFIX is empty then we cannot use it in tools
+	# that expect to be able to chdir() to its value.
+	GIT_PREFIX=${GIT_PREFIX:-.}
+	export GIT_PREFIX
+
 	merge_tool_path="$(get_merge_tool_path "$1")" || exit
 	base_present="$2"
 	status=0
@@ -188,6 +193,7 @@ run_merge_tool () {
 			check_unchanged
 		else
 			"$merge_tool_path" -R -f -d -c "wincmd l" \
+				-c 'cd $GIT_PREFIX' \
 				"$LOCAL" "$REMOTE"
 		fi
 		;;
@@ -199,6 +205,7 @@ run_merge_tool () {
 			check_unchanged
 		else
 			"$merge_tool_path" -R -f -d -c "wincmd l" \
+				-c 'cd $GIT_PREFIX' \
 				"$LOCAL" "$REMOTE"
 		fi
 		;;
-- 
1.7.5.2.663.gfcb11.dirty