[PATCH] Bisect: teach "bisect start" to optionally use one bad and many good revs.

[Christian Couder <chriscool@tuxfamily.org>]

As Junio said:

"One bad commit is fundamentally needed for bisect to run,
and if we beforehand know more good commits, we can narrow
the bisect space down without doing the whole tree checkout
every time we give good commits.  I think it may be a good
idea to have:

    git bisect start [$bad [$good1 $good2...]] [-- <paths>...]

as a short-hand for this command sequence:

    git bisect start
    git bisect bad $bad
    git bisect good $good1 $good2...

That would be a good script-shorterner, without limiting it to
any specific use scenario."

In fact this patch implements:

    git bisect start [<bad> [<good>...]] [--] [<pathspec>...]

I think this is more backward compatible because older script
probably didn't used -- before <pathspec>...

On the other hand, there may be some confusion between revs
(<bad> and <good>...) and <pathspec>... if -- is not used
and if an invalid rev or a pathspec that looks like a rev is
given.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
---

Junio wrote:

> > +	for arg in "$@"; do
> > +	    case "$arg" in --) has_double_dash=1; break ;; esac
> > +	done
>
> Style.  'in "$@"' is superfluous.

Fixed in this patch.

> > +	orig_args="$@"
>
> Doesn't this defeat the whole point of later running 'sq' on it?
> The reason we do sq is to protect whitespaces in pathspecs and
> make the strings correctly split when evaled/sourced.

This should also be fixed.

Thanks,
Christian.


 git-bisect.sh         |  105 ++++++++++++++++++++++++++++++++++++++-----------
 t/t6030-bisect-run.sh |   20 ++++++++-
 2 files changed, 99 insertions(+), 26 deletions(-)

diff --git a/git-bisect.sh b/git-bisect.sh
index 11313a7..2e68e3d 100755
--- a/git-bisect.sh
+++ b/git-bisect.sh
@@ -1,15 +1,24 @@
 #!/bin/sh
 
 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 run <cmd>... 	use <cmd>... to automatically bisect.'
+LONG_USAGE='git bisect start [<bad> [<good>...]] [--] [<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 run <cmd>...
+        use <cmd>... to automatically bisect.'
 
 . git-sh-setup
 require_work_tree
@@ -70,14 +79,48 @@ bisect_start() {
 	#
 	# Get rid of any old bisect state
 	#
-	rm -f "$GIT_DIR/refs/heads/bisect"
-	rm -rf "$GIT_DIR/refs/bisect/"
+	bisect_clean_state
 	mkdir "$GIT_DIR/refs/bisect"
+
+	#
+	# Check for one bad and then some good revisions.
+	#
+	has_double_dash=0
+	for arg; do
+	    case "$arg" in --) has_double_dash=1; break ;; esac
+	done
+	orig_args=$(sq "$@")
+	bad_seen=0
+	while [ $# -gt 0 ]; do
+	    arg="$1"
+	    case "$arg" in
+	    --)
+	        shift
+		break
+		;;
+	    *)
+	        rev=$(git-rev-parse --verify "$arg^{commit}" 2>/dev/null) || {
+		    test $has_double_dash -eq 1 &&
+		        die "'$arg' does not appear to be a valid revision"
+		    break
+		}
+		if [ $bad_seen -eq 0 ]; then
+		    bad_seen=1
+		    bisect_write_bad "$rev"
+		else
+		    bisect_write_good "$rev"
+		fi
+	        shift
+		;;
+	    esac
+        done
+
+	sq "$@" >"$GIT_DIR/BISECT_NAMES"
 	{
 	    printf "git-bisect start"
-	    sq "$@"
-	} >"$GIT_DIR/BISECT_LOG"
-	sq "$@" >"$GIT_DIR/BISECT_NAMES"
+	    echo "$orig_args"
+	} >>"$GIT_DIR/BISECT_LOG"
+	bisect_auto_next
 }
 
 bisect_bad() {
@@ -90,12 +133,17 @@ bisect_bad() {
 	*)
 		usage ;;
 	esac || exit
-	echo "$rev" >"$GIT_DIR/refs/bisect/bad"
-	echo "# bad: "$(git-show-branch $rev) >>"$GIT_DIR/BISECT_LOG"
+	bisect_write_bad "$rev"
 	echo "git-bisect bad $rev" >>"$GIT_DIR/BISECT_LOG"
 	bisect_auto_next
 }
 
+bisect_write_bad() {
+	rev="$1"
+	echo "$rev" >"$GIT_DIR/refs/bisect/bad"
+	echo "# bad: "$(git-show-branch $rev) >>"$GIT_DIR/BISECT_LOG"
+}
+
 bisect_good() {
 	bisect_autostart
         case "$#" in
@@ -106,13 +154,19 @@ bisect_good() {
 	for rev in $revs
 	do
 		rev=$(git-rev-parse --verify "$rev^{commit}") || exit
-		echo "$rev" >"$GIT_DIR/refs/bisect/good-$rev"
-		echo "# good: "$(git-show-branch $rev) >>"$GIT_DIR/BISECT_LOG"
+		bisect_write_good "$rev"
 		echo "git-bisect good $rev" >>"$GIT_DIR/BISECT_LOG"
+
 	done
 	bisect_auto_next
 }
 
+bisect_write_good() {
+	rev="$1"
+	echo "$rev" >"$GIT_DIR/refs/bisect/good-$rev"
+	echo "# good: "$(git-show-branch $rev) >>"$GIT_DIR/BISECT_LOG"
+}
+
 bisect_next_check() {
 	next_ok=no
         test -f "$GIT_DIR/refs/bisect/bad" &&
@@ -190,14 +244,19 @@ bisect_reset() {
 	    usage ;;
 	esac
 	if git checkout "$branch"; then
-		rm -fr "$GIT_DIR/refs/bisect"
-		rm -f "$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"
+		rm -f "$GIT_DIR/head-name"
+		bisect_clean_state
 	fi
 }
 
+bisect_clean_state() {
+	rm -fr "$GIT_DIR/refs/bisect"
+	rm -f "$GIT_DIR/refs/heads/bisect"
+	rm -f "$GIT_DIR/BISECT_LOG"
+	rm -f "$GIT_DIR/BISECT_NAMES"
+	rm -f "$GIT_DIR/BISECT_RUN"
+}
+
 bisect_replay () {
 	test -r "$1" || {
 		echo >&2 "cannot read $1 for replaying"
diff --git a/t/t6030-bisect-run.sh b/t/t6030-bisect-run.sh
index 39c7228..455dc60 100755
--- a/t/t6030-bisect-run.sh
+++ b/t/t6030-bisect-run.sh
@@ -40,8 +40,8 @@ test_expect_success \
 # We want to automatically find the commit that
 # introduced "Another" into hello.
 test_expect_success \
-    'git bisect run simple case' \
-    'echo "#!/bin/sh" > test_script.sh &&
+    '"git bisect run" simple case' \
+    'echo "#"\!"/bin/sh" > test_script.sh &&
      echo "grep Another hello > /dev/null" >> test_script.sh &&
      echo "test \$? -ne 0" >> test_script.sh &&
      chmod +x test_script.sh &&
@@ -49,7 +49,21 @@ test_expect_success \
      git bisect good $HASH1 &&
      git bisect bad $HASH4 &&
      git bisect run ./test_script.sh > my_bisect_log.txt &&
-     grep "$HASH3 is first bad commit" my_bisect_log.txt'
+     grep "$HASH3 is first bad commit" my_bisect_log.txt &&
+     git bisect reset'
+
+# We want to automatically find the commit that
+# introduced "Ciao" into hello.
+test_expect_success \
+    '"git bisect run" with more complex "git bisect start"' \
+    'echo "#"\!"/bin/sh" > test_script.sh &&
+     echo "grep Ciao hello > /dev/null" >> test_script.sh &&
+     echo "test \$? -ne 0" >> test_script.sh &&
+     chmod +x test_script.sh &&
+     git bisect start $HASH4 $HASH1 &&
+     git bisect run ./test_script.sh > my_bisect_log.txt &&
+     grep "$HASH4 is first bad commit" my_bisect_log.txt &&
+     git bisect reset'
 
 #
 #
-- 
1.5.1.rc3.21.g02918