Merge branch 'cc/bisect'

* cc/bisect:
Bisect reset: do nothing when not bisecting.
Bisect: use "$GIT_DIR/BISECT_NAMES" to check if we are bisecting.
Bisect visualize: use "for-each-ref" to list all good refs.
git-bisect: modernize branch shuffling hack
git-bisect: use update-ref to mark good/bad commits
git-bisect: war on "sed"
Bisect reset: remove bisect refs that may have been packed.

diff --combined git-bisect.sh
index 3aac8164c62c1f4af8df76832322df9f25a05b38,6f20a297a5f8812935e79723a52b95306bc22306..7a6521ec3c62b04fe6d4c3e80c418ccc02b4ec65
--- 1/git-bisect.sh
--- 2/git-bisect.sh
+++ b/git-bisect.sh
@@@ -22,7 -22,6 +22,7 @@@ git bisect lo
  git bisect run <cmd>...
          use <cmd>... to automatically bisect.'
  
 +OPTIONS_SPEC=
  . git-sh-setup
  require_work_tree
  
@@@ -37,7 -36,7 +37,7 @@@ sq() 
  }
  
  bisect_autostart() {
-       test -d "$GIT_DIR/refs/bisect" || {
+       test -f "$GIT_DIR/BISECT_NAMES" || {
                echo >&2 'You need to start by "git bisect start"'
                if test -t 0
                then
@@@ -72,7 -71,7 +72,7 @@@ bisect_start() 
                ;;
        refs/heads/*)
                [ -s "$GIT_DIR/head-name" ] && die "won't bisect on seeked tree"
-               echo "$head" | sed 's#^refs/heads/##' >"$GIT_DIR/head-name"
+               echo "${head#refs/heads/}" >"$GIT_DIR/head-name"
                ;;
        *)
                die "Bad HEAD - strange symbolic ref"
@@@ -83,7 -82,6 +83,6 @@@
        # Get rid of any old bisect state
        #
        bisect_clean_state
-       mkdir "$GIT_DIR/refs/bisect"
  
        #
        # Check for one bad and then some good revisions.
@@@ -131,7 -129,7 +130,7 @@@ bisect_write() 
                good|skip)      tag="$state"-"$rev" ;;
                *)              die "Bad bisect_write argument: $state" ;;
        esac
-       echo "$rev" >"$GIT_DIR/refs/bisect/$tag"
+       git update-ref "refs/bisect/$tag" "$rev"
        echo "# $state: "$(git show-branch $rev) >>"$GIT_DIR/BISECT_LOG"
        test -z "$nolog" && echo "git-bisect $state $rev" >>"$GIT_DIR/BISECT_LOG"
  }
@@@ -192,7 -190,7 +191,7 @@@ bisect_next_check() 
                ;;
        *)
                THEN=''
-               test -d "$GIT_DIR/refs/bisect" || {
+               test -f "$GIT_DIR/BISECT_NAMES" || {
                        echo >&2 'You need to start by "git bisect start".'
                        THEN='then '
                }
@@@ -276,8 -274,7 +275,7 @@@ exit_if_skipped_commits () 
        if expr "$_tried" : ".*[|].*" > /dev/null ; then
                echo "There are only 'skip'ped commit left to test."
                echo "The first bad commit could be any of:"
-               echo "$_tried" | sed -e 's/[|]/\
- /g'
+               echo "$_tried" | tr '[|]' '[\012]'
                echo "We cannot bisect more!"
                exit 2
        fi
@@@ -318,20 -315,23 +316,23 @@@ bisect_next() 
        exit_if_skipped_commits "$bisect_rev"
  
        echo "Bisecting: $bisect_nr revisions left to test after this"
-       echo "$bisect_rev" >"$GIT_DIR/refs/heads/new-bisect"
+       git branch -f new-bisect "$bisect_rev"
        git checkout -q new-bisect || exit
-       mv "$GIT_DIR/refs/heads/new-bisect" "$GIT_DIR/refs/heads/bisect" &&
-       GIT_DIR="$GIT_DIR" git symbolic-ref HEAD refs/heads/bisect
+       git branch -M new-bisect bisect
        git show-branch "$bisect_rev"
  }
  
  bisect_visualize() {
        bisect_next_check fail
-       not=`cd "$GIT_DIR/refs" && echo bisect/good-*`
-       eval gitk bisect/bad --not $not -- $(cat "$GIT_DIR/BISECT_NAMES")
+       not=$(git for-each-ref --format='%(refname)' "refs/bisect/good-*")
+       eval gitk refs/bisect/bad --not $not -- $(cat "$GIT_DIR/BISECT_NAMES")
  }
  
  bisect_reset() {
+       test -f "$GIT_DIR/BISECT_NAMES" || {
+               echo "We are not bisecting."
+               return
+       }
        case "$#" in
        0) if [ -s "$GIT_DIR/head-name" ]; then
               branch=`cat "$GIT_DIR/head-name"`
@@@ -351,8 -351,12 +352,12 @@@
  }
  
  bisect_clean_state() {
-       rm -fr "$GIT_DIR/refs/bisect"
-       rm -f "$GIT_DIR/refs/heads/bisect"
+       # There may be some refs packed during bisection.
+       git for-each-ref --format='%(refname) %(objectname)' refs/bisect/\* refs/heads/bisect |
+       while read ref hash
+       do
+               git update-ref -d $ref $hash
+       done
        rm -f "$GIT_DIR/BISECT_LOG"
        rm -f "$GIT_DIR/BISECT_NAMES"
        rm -f "$GIT_DIR/BISECT_RUN"