X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=blobdiff_plain;f=git-bisect.sh;h=0d0e278c92c39f17b368eb6ead781a877bc8caed;hb=6e13921b4f7adcc7316a76c0c4955b85b1589a65;hp=4bcbaceb8bd6a5dc9021b2525f43ae5317a7d46a;hpb=29313449f726f13ecc562cea9856645eade8e3e9;p=git.git

diff --git a/git-bisect.sh b/git-bisect.sh
index 4bcbaceb8..0d0e278c9 100755
--- a/git-bisect.sh
+++ b/git-bisect.sh
@@ -44,7 +44,7 @@ sq() {
 }
 
 bisect_autostart() {
-	test -f "$GIT_DIR/BISECT_NAMES" || {
+	test -s "$GIT_DIR/BISECT_START" || {
 		echo >&2 'You need to start by "git bisect start"'
 		if test -t 0
 		then
@@ -98,7 +98,7 @@ bisect_start() {
 	#
 	# Get rid of any old bisect state.
 	#
-	bisect_clean_state
+	bisect_clean_state || exit
 
 	#
 	# Check for one bad and then some good revisions.
@@ -146,10 +146,10 @@ bisect_start() {
 	#
 	# Write new start state.
 	#
-	sq "$@" >"$GIT_DIR/BISECT_NAMES" &&
 	echo "$start_head" >"$GIT_DIR/BISECT_START" &&
+	sq "$@" >"$GIT_DIR/BISECT_NAMES" &&
 	eval "$eval" &&
-	echo "git-bisect start$orig_args" >>"$GIT_DIR/BISECT_LOG" || exit
+	echo "git bisect start$orig_args" >>"$GIT_DIR/BISECT_LOG" || exit
 	#
 	# Check if we can proceed to the next bisect state.
 	#
@@ -169,7 +169,26 @@ bisect_write() {
 	esac
 	git update-ref "refs/bisect/$tag" "$rev" || exit
 	echo "# $state: $(git show-branch $rev)" >>"$GIT_DIR/BISECT_LOG"
-	test -n "$nolog" || echo "git-bisect $state $rev" >>"$GIT_DIR/BISECT_LOG"
+	test -n "$nolog" || echo "git bisect $state $rev" >>"$GIT_DIR/BISECT_LOG"
+}
+
+is_expected_rev() {
+	test -f "$GIT_DIR/BISECT_EXPECTED_REV" &&
+	test "$1" = $(cat "$GIT_DIR/BISECT_EXPECTED_REV")
+}
+
+mark_expected_rev() {
+	echo "$1" > "$GIT_DIR/BISECT_EXPECTED_REV"
+}
+
+check_expected_revs() {
+	for _rev in "$@"; do
+		if ! is_expected_rev "$_rev"; then
+			rm -f "$GIT_DIR/BISECT_ANCESTORS_OK"
+			rm -f "$GIT_DIR/BISECT_EXPECTED_REV"
+			return
+		fi
+	done
 }
 
 bisect_state() {
@@ -181,7 +200,8 @@ bisect_state() {
 	1,bad|1,good|1,skip)
 		rev=$(git rev-parse --verify HEAD) ||
 			die "Bad rev input: HEAD"
-		bisect_write "$state" "$rev" ;;
+		bisect_write "$state" "$rev"
+		check_expected_revs "$rev" ;;
 	2,bad|*,good|*,skip)
 		shift
 		eval=''
@@ -191,7 +211,8 @@ bisect_state() {
 				die "Bad rev input: $rev"
 			eval="$eval bisect_write '$state' '$sha'; "
 		done
-		eval "$eval" ;;
+		eval "$eval"
+		check_expected_revs "$@" ;;
 	*,bad)
 		die "'git bisect bad' can take only one argument." ;;
 	*)
@@ -220,13 +241,14 @@ bisect_next_check() {
 		if test -t 0
 		then
 			printf >&2 'Are you sure [Y/n]? '
-			case "$(read yesno)" in [Nn]*) exit 1 ;; esac
+			read yesno
+			case "$yesno" in [Nn]*) exit 1 ;; esac
 		fi
 		: bisect without good...
 		;;
 	*)
 		THEN=''
-		test -f "$GIT_DIR/BISECT_NAMES" || {
+		test -s "$GIT_DIR/BISECT_START" || {
 			echo >&2 'You need to start by "git bisect start".'
 			THEN='then '
 		}
@@ -242,33 +264,18 @@ bisect_auto_next() {
 	bisect_next_check && bisect_next || :
 }
 
-eval_rev_list() {
-	_eval="$1"
-
-	eval $_eval
-	res=$?
-
-	if [ $res -ne 0 ]; then
-		echo >&2 "'git rev-list --bisect-vars' failed:"
-		echo >&2 "maybe you mistake good and bad revs?"
-		exit $res
-	fi
-
-	return $res
-}
-
 filter_skipped() {
 	_eval="$1"
 	_skip="$2"
 
 	if [ -z "$_skip" ]; then
-		eval_rev_list "$_eval"
+		eval "$_eval"
 		return
 	fi
 
 	# Let's parse the output of:
 	# "git rev-list --bisect-vars --bisect-all ..."
-	eval_rev_list "$_eval" | while read hash line
+	eval "$_eval" | while read hash line
 	do
 		case "$VARS,$FOUND,$TRIED,$hash" in
 			# We display some vars.
@@ -331,20 +338,133 @@ exit_if_skipped_commits () {
 	fi
 }
 
+bisect_checkout() {
+	_rev="$1"
+	_msg="$2"
+	echo "Bisecting: $_msg"
+	mark_expected_rev "$_rev"
+	git checkout -q "$_rev" || exit
+	git show-branch "$_rev"
+}
+
+is_among() {
+	_rev="$1"
+	_list="$2"
+	case "$_list" in *$_rev*) return 0 ;; esac
+	return 1
+}
+
+handle_bad_merge_base() {
+	_badmb="$1"
+	_good="$2"
+	if is_expected_rev "$_badmb"; then
+		cat >&2 <<EOF
+The merge base $_badmb is bad.
+This means the bug has been fixed between $_badmb and [$_good].
+EOF
+		exit 3
+	else
+		cat >&2 <<EOF
+Some good revs are not ancestor of the bad rev.
+git bisect cannot work properly in this case.
+Maybe you mistake good and bad revs?
+EOF
+		exit 1
+	fi
+}
+
+handle_skipped_merge_base() {
+	_mb="$1"
+	_bad="$2"
+	_good="$3"
+	cat >&2 <<EOF
+Warning: the merge base between $_bad and [$_good] must be skipped.
+So we cannot be sure the first bad commit is between $_mb and $_bad.
+We continue anyway.
+EOF
+}
+
+#
+# "check_merge_bases" checks that merge bases are not "bad".
+#
+# - If one is "good", that's good, we have nothing to do.
+# - If one is "bad", it means the user assumed something wrong
+# and we must exit.
+# - If one is "skipped", we can't know but we should warn.
+# - If we don't know, we should check it out and ask the user to test.
+#
+# In the last case we will return 1, and otherwise 0.
+#
+check_merge_bases() {
+	_bad="$1"
+	_good="$2"
+	_skip="$3"
+	for _mb in $(git merge-base --all $_bad $_good)
+	do
+		if is_among "$_mb" "$_good"; then
+			continue
+		elif test "$_mb" = "$_bad"; then
+			handle_bad_merge_base "$_bad" "$_good"
+		elif is_among "$_mb" "$_skip"; then
+			handle_skipped_merge_base "$_mb" "$_bad" "$_good"
+		else
+			bisect_checkout "$_mb" "a merge base must be tested"
+			return 1
+		fi
+	done
+	return 0
+}
+
+#
+# "check_good_are_ancestors_of_bad" checks that all "good" revs are
+# ancestor of the "bad" rev.
+#
+# If that's not the case, we need to check the merge bases.
+# If a merge base must be tested by the user we return 1 and
+# otherwise 0.
+#
+check_good_are_ancestors_of_bad() {
+	test -f "$GIT_DIR/BISECT_ANCESTORS_OK" &&
+		return
+
+	_bad="$1"
+	_good=$(echo $2 | sed -e 's/\^//g')
+	_skip="$3"
+
+	# Bisecting with no good rev is ok
+	test -z "$_good" && return
+
+	_side=$(git rev-list $_good ^$_bad)
+	if test -n "$_side"; then
+		# Return if a checkout was done
+		check_merge_bases "$_bad" "$_good" "$_skip" || return
+	fi
+
+	: > "$GIT_DIR/BISECT_ANCESTORS_OK"
+
+	return 0
+}
+
 bisect_next() {
 	case "$#" in 0) ;; *) usage ;; esac
 	bisect_autostart
 	bisect_next_check good
 
+	# Get bad, good and skipped revs
+	bad=$(git rev-parse --verify refs/bisect/bad) &&
+	good=$(git for-each-ref --format='^%(objectname)' \
+		"refs/bisect/good-*" | tr '\012' ' ') &&
 	skip=$(git for-each-ref --format='%(objectname)' \
 		"refs/bisect/skip-*" | tr '\012' ' ') || exit
 
+	# Maybe some merge bases must be tested first
+	check_good_are_ancestors_of_bad "$bad" "$good" "$skip"
+	# Return now if a checkout has already been done
+	test "$?" -eq "1" && return
+
+	# Get bisection information
 	BISECT_OPT=''
 	test -n "$skip" && BISECT_OPT='--bisect-all'
-
-	bad=$(git rev-parse --verify refs/bisect/bad) &&
-	good=$(git for-each-ref --format='^%(objectname)' \
-		"refs/bisect/good-*" | tr '\012' ' ') &&
 	eval="git rev-list --bisect-vars $BISECT_OPT $good $bad --" &&
 	eval="$eval $(cat "$GIT_DIR/BISECT_NAMES")" &&
 	eval=$(filter_skipped "$eval" "$skip") &&
@@ -365,9 +485,7 @@ bisect_next() {
 	# commit is also a "skip" commit (see above).
 	exit_if_skipped_commits "$bisect_rev"
 
-	echo "Bisecting: $bisect_nr revisions left to test after this"
-	git checkout -q "$bisect_rev" || exit
-	git show-branch "$bisect_rev"
+	bisect_checkout "$bisect_rev" "$bisect_nr revisions left to test after this"
 }
 
 bisect_visualize() {
@@ -392,16 +510,12 @@ bisect_visualize() {
 }
 
 bisect_reset() {
-	test -f "$GIT_DIR/BISECT_NAMES" || {
+	test -s "$GIT_DIR/BISECT_START" || {
 		echo "We are not bisecting."
 		return
 	}
 	case "$#" in
-	0) if [ -s "$GIT_DIR/BISECT_START" ]; then
-	       branch=`cat "$GIT_DIR/BISECT_START"`
-	   else
-	       branch=master
-	   fi ;;
+	0) branch=$(cat "$GIT_DIR/BISECT_START") ;;
 	1) git show-ref --verify --quiet -- "refs/heads/$1" ||
 	       die "$1 does not seem to be a valid branch"
 	   branch="$1" ;;
@@ -416,22 +530,29 @@ bisect_clean_state() {
 	git for-each-ref --format='%(refname) %(objectname)' refs/bisect/\* |
 	while read ref hash
 	do
-		git update-ref -d $ref $hash
+		git update-ref -d $ref $hash || exit
 	done
-	rm -f "$GIT_DIR/BISECT_START"
-	rm -f "$GIT_DIR/BISECT_LOG"
-	rm -f "$GIT_DIR/BISECT_NAMES"
-	rm -f "$GIT_DIR/BISECT_RUN"
+	rm -f "$GIT_DIR/BISECT_EXPECTED_REV" &&
+	rm -f "$GIT_DIR/BISECT_ANCESTORS_OK" &&
+	rm -f "$GIT_DIR/BISECT_LOG" &&
+	rm -f "$GIT_DIR/BISECT_NAMES" &&
+	rm -f "$GIT_DIR/BISECT_RUN" &&
 	# Cleanup head-name if it got left by an old version of git-bisect
-	rm -f "$GIT_DIR/head-name"
+	rm -f "$GIT_DIR/head-name" &&
+
+	rm -f "$GIT_DIR/BISECT_START"
 }
 
 bisect_replay () {
 	test -r "$1" || die "cannot read $1 for replaying"
 	bisect_reset
-	while read bisect command rev
+	while read git bisect command rev
 	do
-		test "$bisect" = "git-bisect" || continue
+		test "$git $bisect" = "git bisect" -o "$git" = "git-bisect" || continue
+		if test "$git" = "git-bisect"; then
+			rev="$command"
+			command="$bisect"
+		fi
 		case "$command" in
 		start)
 			cmd="bisect_start $rev"