Properly git-bisect reset after bisecting from non-master head

git-bisect reset without an argument would return to master even
if the bisecting started at a non-master branch. This patch makes
it save the original branch name to .git/head-name and restore it
afterwards.

This is also compatible with Cogito and cg-seek, so cg-status will
show that we are seeked on the bisect branch and cg-reset will
properly restore the original branch.

git-bisect start will refuse to work if it is not on a bisect but
.git/head-name exists; this is to protect against conflicts with
other seeking tools.

Signed-off-by: Petr Baudis <pasky@suse.cz>
Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/git-bisect.sh b/git-bisect.sh
index 51e1e44..3c024aa 100755 (executable)
--- a/git-bisect.sh
+++ b/git-bisect.sh
@@ -49,9 +49,16 @@ bisect_start() {
        die "Bad HEAD - I need a symbolic ref"
        case "$head" in
        refs/heads/bisect*)
-               git checkout master || exit
+               if [ -s "$GIT_DIR/head-name" ]; then
+                   branch=`cat "$GIT_DIR/head-name"`
+               else
+                   branch=master
+               fi
+               git checkout $branch || exit
                ;;
        refs/heads/*)
+               [ -s "$GIT_DIR/head-name" ] && die "won't bisect on seeked tree"
+               echo "$head" | sed 's#^refs/heads/##' >"$GIT_DIR/head-name"
                ;;
        *)
                die "Bad HEAD - strange symbolic ref"
@@ -159,7 +166,11 @@ bisect_visualize() {
 
 bisect_reset() {
        case "$#" in
-       0) branch=master ;;
+       0) if [ -s "$GIT_DIR/head-name" ]; then
+              branch=`cat "$GIT_DIR/head-name"`
+          else
+              branch=master
+          fi ;;
        1) test -f "$GIT_DIR/refs/heads/$1" || {
               echo >&2 "$1 does not seem to be a valid branch"
               exit 1
@@ -170,7 +181,7 @@ bisect_reset() {
        esac
        git checkout "$branch" &&
        rm -fr "$GIT_DIR/refs/bisect"
-       rm -f "$GIT_DIR/refs/heads/bisect"
+       rm -f "$GIT_DIR/refs/heads/bisect" "$GIT_DIR/head-name"
        rm -f "$GIT_DIR/BISECT_LOG"
 }