Bisect: implement "git bisect run <cmd>..." to automatically bisect.

This idea was suggested by Bill Lear
(Message-ID: <17920.38942.364466.642979@lisa.zopyra.com>)
and I think it is a very good one.

This patch adds a new test file for "git bisect run", but there
is currently only one basic test.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>

1 files changed, 51 insertions, 3 deletions

diff --git a/git-bisect.sh b/git-bisect.sh
index dbce0dfec..3043f6551 100755
--- a/git-bisect.sh
+++ b/git-bisect.sh
@@ -1,14 +1,15 @@
 #!/bin/sh
 
-USAGE='[start|bad|good|next|reset|visualize|replay|log]'
+USAGE='[start|bad|good|next|reset|visualize|replay|log|run]'
 LONG_USAGE='git bisect start [<pathspec>]	reset bisect state and start bisection.
 git bisect bad [<rev>]		mark <rev> a known-bad revision.
 git bisect good [<rev>...]	mark <rev>... known-good revisions.
 git bisect next			find next bisection to test and check it out.
 git bisect reset [<branch>]	finish bisection search and go back to branch.
 git bisect visualize            show bisect status in gitk.
-git bisect replay <logfile>	replay bisection log
-git bisect log			show bisect log.'
+git bisect replay <logfile>	replay bisection log.
+git bisect log			show bisect log.
+git bisect run <cmd>... 	use <cmd>... to automatically bisect.'
 
 . git-sh-setup
 require_work_tree
@@ -185,6 +186,7 @@ bisect_reset() {
 		rm -f "$GIT_DIR/refs/heads/bisect" "$GIT_DIR/head-name"
 		rm -f "$GIT_DIR/BISECT_LOG"
 		rm -f "$GIT_DIR/BISECT_NAMES"
+		rm -f "$GIT_DIR/BISECT_RUN"
 	fi
 }
 
@@ -220,6 +222,50 @@ bisect_replay () {
 	bisect_auto_next
 }
 
+bisect_run () {
+    while true
+    do
+      echo "running $@"
+      "$@"
+      res=$?
+
+      # Check for really bad run error.
+      if [ $res -lt 0 -o $res -ge 128 ]; then
+	  echo >&2 "bisect run failed:"
+	  echo >&2 "exit code $res from '$@' is < 0 or >= 128"
+	  exit $res
+      fi
+
+      # Use "bisect_good" or "bisect_bad"
+      # depending on run success or failure.
+      if [ $res -gt 0 ]; then
+	  next_bisect='bisect_bad'
+      else
+	  next_bisect='bisect_good'
+      fi
+
+      # We have to use a subshell because bisect_good or
+      # bisect_bad functions can exit.
+      ( $next_bisect > "$GIT_DIR/BISECT_RUN" )
+      res=$?
+
+      cat "$GIT_DIR/BISECT_RUN"
+
+      if [ $res -ne 0 ]; then
+	  echo >&2 "bisect run failed:"
+	  echo >&2 "$next_bisect exited with error code $res"
+	  exit $res
+      fi
+
+      if grep "is first bad commit" "$GIT_DIR/BISECT_RUN" > /dev/null; then
+	  echo "bisect run success"
+	  exit 0;
+      fi
+
+    done
+}
+
+
 case "$#" in
 0)
     usage ;;
@@ -244,6 +290,8 @@ case "$#" in
 	bisect_replay "$@" ;;
     log)
 	cat "$GIT_DIR/BISECT_LOG" ;;
+    run)
+        bisect_run "$@" ;;
     *)
         usage ;;
     esac