[WIP PATCH 1/3] git bisect old/new

[WIP PATCH 1/3] git bisect old/new

[Antoine Delaite]

From: Christian Couder <chriscool@tuxfamily.org>

When not looking for a regression during a bisect but for a fix or a
change in another given property, it can be confusing to use 'good'
and 'bad'.

This patch introduce `git bisect new` and `git bisect old` as an
alternative to 'bad' and good': the commits which have the most
recent version of the property must be marked as `new` and the ones
with the older version as `old`.

The output will be the first commit after the change in the property.
During a new/old bisect session you cannot use bad/good commands and
vice-versa.

`git bisect replay` works fine for old/new bisect sessions.

Some commands are still not available for old/new:

     * git bisect start [<new> [<old>...]] is not possible: the
       commits will be treated as bad and good.
     * git rev-list --bisect does not treat the revs/bisect/new and
       revs/bisect/old-SHA1 files.
     * git bisect visualize seem to work partially: the tags are
       displayed correctly but the tree is not limited to the bisect
       section.

Related discussions:

	- http://thread.gmane.org/gmane.comp.version-control.git/86063
		introduced bisect fix unfixed to find fix.
	- http://thread.gmane.org/gmane.comp.version-control.git/182398
		discussion around bisect yes/no or old/new.
	- http://thread.gmane.org/gmane.comp.version-control.git/199758
		last discussion and reviews

Signed-off-by: Antoine Delaite <antoine.delaite@ensimag.grenoble-inp.fr>
Signed-off-by: Louis Stuber <stuberl@ensimag.grenoble-inp.fr>
Signed-off-by: Valentin Duperray <Valentin.Duperray@ensimag.imag.fr>
Signed-off-by: Franck Jonas <Franck.Jonas@ensimag.imag.fr>
Signed-off-by: Lucien Kong <Lucien.Kong@ensimag.imag.fr>
Signed-off-by: Thomas Nguy <Thomas.Nguy@ensimag.imag.fr>
Signed-off-by: Huynh Khoi Nguyen Nguyen <Huynh-Khoi-Nguyen.Nguyen@ensimag.imag.fr>
Signed-off-by: Matthieu Moy <Matthieu.Moy@grenoble-inp.fr>
---
We took account of most of the "easy" reviews that were discuted two years ago.
We hope we didn't missed any.
http://thread.gmane.org/gmane.comp.version-control.git/199758

We corrected various issues that were not reported: 
-one that caused a "fatal ... not a valid ref" at the end of the bisection.
-the autostart was causing issues, the following lines were working :
git bisect new HEAD
git bisect bad HEAD
git bisect good aGoodCommit

The hard review which we were thinking on was the issue of the maintaining
of old/new and allow easy support of new "tags" like yes/no in the future.
I tried to remove the maximum of bad/good and old/new which were hard wrote in
the code but I'm not completly satisfied. This patch is clearly a v1.

We're currently working on:

* rebasing the history of the patch
* git rev-list --bisect does not treat the revs/bisect/new and
revs/bisect/old-SHA1 files.
* git bisect visualize seem to work partially: the tags are displayed
correctly but the tree is not limited to the bisect section.
* adding tests about old/new

Some other problems that might also be considerred later :
* change/add valid terms (e.g "unfixed/fixed" instead of "old/new")
*
* git bisect start [<new> [<old>...]] is not possible: the commits
will be treated as bad and good.


 Documentation/git-bisect.txt |  43 +++++++++++++-
 bisect.c                     |  83 ++++++++++++++++++++-------
 git-bisect.sh                | 132 ++++++++++++++++++++++++++++++++-----------
 t/t6030-bisect-porcelain.sh  |  40 +++++++++++++
 4 files changed, 243 insertions(+), 55 deletions(-)
 mode change 100755 => 100644 git-bisect.sh

diff --git a/Documentation/git-bisect.txt b/Documentation/git-bisect.txt
index 4cb52a7..12c7711 100644
--- a/Documentation/git-bisect.txt
+++ b/Documentation/git-bisect.txt
@@ -18,8 +18,8 @@ on the subcommand:
 
  git bisect help
  git bisect start [--no-checkout] [<bad> [<good>...]] [--] [<paths>...]
- git bisect bad [<rev>]
- git bisect good [<rev>...]
+ git bisect (bad|new) [<rev>]
+ git bisect (good|old) [<rev>...]
  git bisect skip [(<rev>|<range>)...]
  git bisect reset [<commit>]
  git bisect visualize
@@ -104,6 +104,33 @@ For example, `git bisect reset HEAD` will leave you on the current
 bisection commit and avoid switching commits at all, while `git bisect
 reset bisect/bad` will check out the first bad revision.
 
+
+Alternative terms: bisect new and bisect old
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+If you are not at ease with the terms "bad" and "good", perhaps
+because you are looking for the commit that introduced a fix, you can
+alternatively use "new" and "old" instead.
+But note that you cannot mix "bad" and good" with "new" and "old".
+
+------------------------------------------------
+git bisect new [<rev>]
+------------------------------------------------
+
+Marks the commit as new, which means the version is fixed.
+It is the equivalent of "git bisect bad [<rev>]".
+
+------------------------------------------------
+git bisect old [<rev>...]
+------------------------------------------------
+
+Marks the commit as old, which means the bug is present.
+It is the equivalent of "git bisect good [<rev>...]".
+
+You must run `git bisect start` without commits as argument and run
+`git bisect new <rev>`/`git bisect old <rev>...` after to add the
+commits.
+
 Bisect visualize
 ~~~~~~~~~~~~~~~~
 
@@ -379,6 +406,18 @@ In this case, when 'git bisect run' finishes, bisect/bad will refer to a commit
 has at least one parent whose reachable graph is fully traversable in the sense
 required by 'git pack objects'.
 
+* Look for a fix instead of a regression in the code
++
+------------
+$ git bisect start
+$ git bisect new		# Current version is fixed
+$ git bisect old bugged_version	# bugged_version was the last version
+				# known to be unfixed
+------------
++
+The "new" commits are the fixed ones and the "old" commits are the unfixed ones.
+At the end of the bisect session, you will have the first fixed commit.
+
 
 SEE ALSO
 --------
diff --git a/bisect.c b/bisect.c
index 10f5e57..d6c19fd 100644
--- a/bisect.c
+++ b/bisect.c
@@ -21,6 +21,9 @@ static const char *argv_checkout[] = {"checkout", "-q", NULL, "--", NULL};
 static const char *argv_show_branch[] = {"show-branch", NULL, NULL};
 static const char *argv_update_ref[] = {"update-ref", "--no-deref", "BISECT_HEAD", NULL, NULL};
 
+static const char *bisect_bad;
+static const char *bisect_good;
+
 /* Remember to update object flag allocation in object.h */
 #define COUNTED		(1u<<16)
 
@@ -403,10 +406,11 @@ struct commit_list *find_bisection(struct commit_list *list,
 static int register_ref(const char *refname, const unsigned char *sha1,
 			int flags, void *cb_data)
 {
-	if (!strcmp(refname, "bad")) {
+	if (!strcmp(refname, bisect_bad)) {
 		current_bad_oid = xmalloc(sizeof(*current_bad_oid));
 		hashcpy(current_bad_oid->hash, sha1);
-	} else if (starts_with(refname, "good-")) {
+	} else if (starts_with(refname, "good-") ||
+		   starts_with(refname, "old-")) {
 		sha1_array_append(&good_revs, sha1);
 	} else if (starts_with(refname, "skip-")) {
 		sha1_array_append(&skipped_revs, sha1);
@@ -634,7 +638,7 @@ static void exit_if_skipped_commits(struct commit_list *tried,
 		return;
 
 	printf("There are only 'skip'ped commits left to test.\n"
-	       "The first bad commit could be any of:\n");
+	       "The first %s commit could be any of:\n", bisect_bad);
 	print_commit_list(tried, "%s\n", "%s\n");
 	if (bad)
 		printf("%s\n", oid_to_hex(bad));
@@ -732,18 +736,25 @@ static void handle_bad_merge_base(void)
 	if (is_expected_rev(current_bad_oid)) {
 		char *bad_hex = oid_to_hex(current_bad_oid);
 		char *good_hex = join_sha1_array_hex(&good_revs, ' ');
-
-		fprintf(stderr, "The merge base %s is bad.\n"
-			"This means the bug has been fixed "
-			"between %s and [%s].\n",
-			bad_hex, bad_hex, good_hex);
-
+		if (!strcmp(bisect_bad,"bad")) {
+			fprintf(stderr, "The merge base %s is bad.\n"
+				"This means the bug has been fixed "
+				"between %s and [%s].\n",
+				bad_hex, bad_hex, good_hex);
+		} else {
+			fprintf(stderr, "The merge base %s is new.\n"
+				"The property has changed "
+				"between %s and [%s].\n",
+				bad_hex, bad_hex, good_hex);
+		}
 		exit(3);
 	}
 
-	fprintf(stderr, "Some good revs are not ancestor of the bad rev.\n"
+	fprintf(stderr, "Some %s revs are not ancestor of the %s rev.\n"
 		"git bisect cannot work properly in this case.\n"
-		"Maybe you mistake good and bad revs?\n");
+		"Maybe you mistook %s and %s revs?\n",
+		bisect_good, bisect_bad, bisect_good,
+		bisect_bad);
 	exit(1);
 }
 
@@ -755,19 +766,19 @@ static void handle_skipped_merge_base(const unsigned char *mb)
 
 	warning("the merge base between %s and [%s] "
 		"must be skipped.\n"
-		"So we cannot be sure the first bad commit is "
+		"So we cannot be sure the first %s commit is "
 		"between %s and %s.\n"
 		"We continue anyway.",
-		bad_hex, good_hex, mb_hex, bad_hex);
+		bad_hex, good_hex, bisect_bad, mb_hex, bad_hex);
 	free(good_hex);
 }
 
 /*
- * "check_merge_bases" checks that merge bases are not "bad".
+ * "check_merge_bases" checks that merge bases are not "bad" (or "new").
  *
- * - If one is "bad", it means the user assumed something wrong
+ * - If one is "bad" (or "new"), it means the user assumed something wrong
  * and we must exit with a non 0 error code.
- * - If one is "good", that's good, we have nothing to do.
+ * - If one is "good" (or "old"), that's good, we have nothing to do.
  * - 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.
  */
@@ -839,7 +850,7 @@ static void check_good_are_ancestors_of_bad(const char *prefix, int no_checkout)
 	int fd;
 
 	if (!current_bad_oid)
-		die("a bad revision is needed");
+		die("a %s revision is needed", bisect_bad);
 
 	/* Check if file BISECT_ANCESTORS_OK exists. */
 	if (!stat(filename, &st) && S_ISREG(st.st_mode))
@@ -890,6 +901,31 @@ static void show_diff_tree(const char *prefix, struct commit *commit)
 }
 
 /*
+ * The terms used for this bisect session are stocked in
+ * BISECT_TERMS: it can be bad/good or new/old.
+ * We read them and stock them to adapt the messages
+ * accordingly. Default is bad/good.
+ */
+void read_bisect_terms(void)
+{
+	struct strbuf str = STRBUF_INIT;
+	const char *filename = git_path("BISECT_TERMS");
+	FILE *fp = fopen(filename, "r");
+
+	if (!fp) {
+		bisect_bad = "bad";
+		bisect_good = "good";
+	} else {
+	strbuf_getline(&str, fp, '\n');
+	bisect_bad = strbuf_detach(&str, NULL);
+	strbuf_getline(&str, fp, '\n');
+	bisect_good = strbuf_detach(&str, NULL);
+	}
+	strbuf_release(&str);
+	fclose(fp);
+}
+
+/*
  * We use the convention that exiting with an exit code 10 means that
  * the bisection process finished successfully.
  * In this case the calling shell script should exit 0.
@@ -905,6 +941,7 @@ int bisect_next_all(const char *prefix, int no_checkout)
 	const unsigned char *bisect_rev;
 	char bisect_rev_hex[GIT_SHA1_HEXSZ + 1];
 
+	read_bisect_terms();
 	if (read_bisect_refs())
 		die("reading bisect refs failed");
 
@@ -926,8 +963,10 @@ int bisect_next_all(const char *prefix, int no_checkout)
 		 */
 		exit_if_skipped_commits(tried, NULL);
 
-		printf("%s was both good and bad\n",
-		       oid_to_hex(current_bad_oid));
+		printf("%s was both %s and %s\n",
+		       oid_to_hex(current_bad_oid),
+		       bisect_good,
+		       bisect_bad);
 		exit(1);
 	}
 
@@ -942,7 +981,8 @@ int bisect_next_all(const char *prefix, int no_checkout)
 
 	if (!hashcmp(bisect_rev, current_bad_oid->hash)) {
 		exit_if_skipped_commits(tried, current_bad_oid);
-		printf("%s is the first bad commit\n", bisect_rev_hex);
+		printf("%s is the first %s commit\n", bisect_rev_hex,
+			bisect_bad);
 		show_diff_tree(prefix, revs.commits->item);
 		/* This means the bisection process succeeded. */
 		exit(10);
@@ -954,6 +994,9 @@ int bisect_next_all(const char *prefix, int no_checkout)
 	       "(roughly %d step%s)\n", nr, (nr == 1 ? "" : "s"),
 	       steps, (steps == 1 ? "" : "s"));
 
+	free((char*)bisect_bad);
+	free((char*)bisect_good);
+
 	return bisect_checkout(bisect_rev_hex, no_checkout);
 }
 
diff --git a/git-bisect.sh b/git-bisect.sh
old mode 100755
new mode 100644
index ae3fec2..109bd65
--- a/git-bisect.sh
+++ b/git-bisect.sh
@@ -1,14 +1,16 @@
 #!/bin/sh
 
-USAGE='[help|start|bad|good|skip|next|reset|visualize|replay|log|run]'
+USAGE='[help|start|bad|good|skip|next|reset|visualize|replay|log|run|new|old]'
 LONG_USAGE='git bisect help
 	print this long help message.
 git bisect start [--no-checkout] [<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 (bad|new) [<rev>]
+	mark <rev> a known-bad revision/
+		a revision after change in a given property.
+git bisect (good|old) [<rev>...]
+	mark <rev>... known-good revisions/
+		revisions before change in a given property.
 git bisect skip [(<rev>|<range>)...]
 	mark <rev>... untestable revisions.
 git bisect next
@@ -32,6 +34,8 @@ OPTIONS_SPEC=
 
 _x40='[0-9a-f][0-9a-f][0-9a-f][0-9a-f][0-9a-f]'
 _x40="$_x40$_x40$_x40$_x40$_x40$_x40$_x40$_x40"
+BISECT_BAD="bad"
+BISECT_GOOD="good"
 
 bisect_head()
 {
@@ -75,6 +79,7 @@ bisect_start() {
 	orig_args=$(git rev-parse --sq-quote "$@")
 	bad_seen=0
 	eval=''
+	start_bad_good=0
 	if test "z$(git rev-parse --is-bare-repository)" != zfalse
 	then
 		mode=--no-checkout
@@ -99,6 +104,10 @@ bisect_start() {
 				die "$(eval_gettext "'\$arg' does not appear to be a valid revision")"
 				break
 			}
+
+			# by default, if the user didnt type --fix
+			start_bad_good=1
+
 			case $bad_seen in
 			0) state='bad' ; bad_seen=1 ;;
 			*) state='good' ;;
@@ -170,6 +179,11 @@ bisect_start() {
 	} &&
 	git rev-parse --sq-quote "$@" >"$GIT_DIR/BISECT_NAMES" &&
 	eval "$eval true" &&
+	if test $start_bad_good -eq 1 -a ! -s "$GIT_DIR/BISECT_TERMS"
+	then
+		echo "$BISECT_BAD" >"$GIT_DIR/BISECT_TERMS" &&
+		echo "$BISECT_GOOD" >>"$GIT_DIR/BISECT_TERMS"
+	fi &&
 	echo "git bisect start$orig_args" >>"$GIT_DIR/BISECT_LOG" || exit
 	#
 	# Check if we can proceed to the next bisect state.
@@ -184,9 +198,12 @@ bisect_write() {
 	rev="$2"
 	nolog="$3"
 	case "$state" in
-		bad)		tag="$state" ;;
-		good|skip)	tag="$state"-"$rev" ;;
-		*)		die "$(eval_gettext "Bad bisect_write argument: \$state")" ;;
+		"$BISECT_BAD")
+			tag="$state" ;;
+		"$BISECT_GOOD"|skip)
+			tag="$state"-"$rev" ;;
+		*)
+			die "$(eval_gettext "Bad bisect_write argument: \$state")" ;;
 	esac
 	git update-ref "refs/bisect/$tag" "$rev" || exit
 	echo "# $state: $(git show-branch $rev)" >>"$GIT_DIR/BISECT_LOG"
@@ -227,15 +244,16 @@ bisect_skip() {
 bisect_state() {
 	bisect_autostart
 	state=$1
+	check_and_set_terms $state
 	case "$#,$state" in
 	0,*)
 		die "$(gettext "Please call 'bisect_state' with at least one argument.")" ;;
-	1,bad|1,good|1,skip)
+	1,"$BISECT_BAD"|1,"$BISECT_GOOD"|1,skip)
 		rev=$(git rev-parse --verify $(bisect_head)) ||
 			die "$(gettext "Bad rev input: $(bisect_head)")"
 		bisect_write "$state" "$rev"
 		check_expected_revs "$rev" ;;
-	2,bad|*,good|*,skip)
+	2,"$BISECT_BAD"|*,"$BISECT_GOOD"|*,skip)
 		shift
 		hash_list=''
 		for rev in "$@"
@@ -249,8 +267,8 @@ bisect_state() {
 			bisect_write "$state" "$rev"
 		done
 		check_expected_revs $hash_list ;;
-	*,bad)
-		die "$(gettext "'git bisect bad' can take only one argument.")" ;;
+	*,"$BISECT_BAD")
+		die "$(gettext "'git bisect $BISECT_BAD' can take only one argument.")" ;;
 	*)
 		usage ;;
 	esac
@@ -259,21 +277,21 @@ bisect_state() {
 
 bisect_next_check() {
 	missing_good= missing_bad=
-	git show-ref -q --verify refs/bisect/bad || missing_bad=t
-	test -n "$(git for-each-ref "refs/bisect/good-*")" || missing_good=t
+	git show-ref -q --verify refs/bisect/$BISECT_BAD || missing_bad=t
+	test -n "$(git for-each-ref "refs/bisect/$BISECT_GOOD-*")" || missing_good=t
 
 	case "$missing_good,$missing_bad,$1" in
 	,,*)
-		: have both good and bad - ok
+		: have both $BISECT_GOOD and $BISECT_BAD - ok
 		;;
 	*,)
 		# do not have both but not asked to fail - just report.
 		false
 		;;
-	t,,good)
-		# have bad but not good.  we could bisect although
+	t,,"$BISECT_GOOD")
+		# have bad (or new) but not good (or old).  we could bisect although
 		# this is less optimum.
-		gettextln "Warning: bisecting only with a bad commit." >&2
+		gettextln "Warning: bisecting only with a $BISECT_BAD commit." >&2
 		if test -t 0
 		then
 			# TRANSLATORS: Make sure to include [Y] and [n] in your
@@ -283,18 +301,18 @@ bisect_next_check() {
 			read yesno
 			case "$yesno" in [Nn]*) exit 1 ;; esac
 		fi
-		: bisect without good...
+		: bisect without $BISECT_GOOD...
 		;;
 	*)
 
 		if test -s "$GIT_DIR/BISECT_START"
 		then
-			gettextln "You need to give me at least one good and one bad revision.
-(You can use \"git bisect bad\" and \"git bisect good\" for that.)" >&2
+			gettextln "You need to give me at least one $(bisect_voc bad) and one $(bisect_voc good) revision.
+(You can use \"git bisect $(bisect_voc bad)\" and \"git bisect $(bisect_voc good)\" for that.)" >&2
 		else
 			gettextln "You need to start by \"git bisect start\".
-You then need to give me at least one good and one bad revision.
-(You can use \"git bisect bad\" and \"git bisect good\" for that.)" >&2
+You then need to give me at least one $(bisect_voc good) and one $(bisect_voc bad) revision.
+(You can use \"git bisect $(bisect_voc bad)\" and \"git bisect $(bisect_voc good)\" for that.)" >&2
 		fi
 		exit 1 ;;
 	esac
@@ -307,7 +325,7 @@ bisect_auto_next() {
 bisect_next() {
 	case "$#" in 0) ;; *) usage ;; esac
 	bisect_autostart
-	bisect_next_check good
+	bisect_next_check $BISECT_GOOD
 
 	# Perform all bisection computation, display and checkout
 	git bisect--helper --next-all $(test -f "$GIT_DIR/BISECT_HEAD" && echo --no-checkout)
@@ -316,15 +334,15 @@ bisect_next() {
 	# Check if we should exit because bisection is finished
 	if test $res -eq 10
 	then
-		bad_rev=$(git show-ref --hash --verify refs/bisect/bad)
+		bad_rev=$(git show-ref --hash --verify refs/bisect/$BISECT_BAD)
 		bad_commit=$(git show-branch $bad_rev)
 		echo "# first bad commit: $bad_commit" >>"$GIT_DIR/BISECT_LOG"
 		exit 0
 	elif test $res -eq 2
 	then
 		echo "# only skipped commits left to test" >>"$GIT_DIR/BISECT_LOG"
-		good_revs=$(git for-each-ref --format="%(objectname)" "refs/bisect/good-*")
-		for skipped in $(git rev-list refs/bisect/bad --not $good_revs)
+		good_revs=$(git for-each-ref --format="%(objectname)" "refs/bisect/$BISECT_GOOD-*")
+		for skipped in $(git rev-list refs/bisect/$BISECT_BAD --not $good_revs)
 		do
 			skipped_commit=$(git show-branch $skipped)
 			echo "# possible first bad commit: $skipped_commit" >>"$GIT_DIR/BISECT_LOG"
@@ -397,6 +415,7 @@ bisect_clean_state() {
 	rm -f "$GIT_DIR/BISECT_LOG" &&
 	rm -f "$GIT_DIR/BISECT_NAMES" &&
 	rm -f "$GIT_DIR/BISECT_RUN" &&
+	rm -f "$GIT_DIR/BISECT_TERMS" &&
 	# Cleanup head-name if it got left by an old version of git-bisect
 	rm -f "$GIT_DIR/head-name" &&
 	git update-ref -d --no-deref BISECT_HEAD &&
@@ -417,11 +436,13 @@ bisect_replay () {
 			rev="$command"
 			command="$bisect"
 		fi
+		get_terms
+		check_and_set_terms "$command"
 		case "$command" in
 		start)
 			cmd="bisect_start $rev"
 			eval "$cmd" ;;
-		good|bad|skip)
+		good|bad|skip|old|new)
 			bisect_write "$command" "$rev" ;;
 		*)
 			die "$(gettext "?? what are you talking about?")" ;;
@@ -455,9 +476,9 @@ exit code \$res from '\$command' is < 0 or >= 128" >&2
 			state='skip'
 		elif [ $res -gt 0 ]
 		then
-			state='bad'
+			state="$BISECT_BAD"
 		else
-			state='good'
+			state="$BISECT_GOOD"
 		fi
 
 		# We have to use a subshell because "bisect_state" can exit.
@@ -466,7 +487,7 @@ exit code \$res from '\$command' is < 0 or >= 128" >&2
 
 		cat "$GIT_DIR/BISECT_RUN"
 
-		if sane_grep "first bad commit could be any of" "$GIT_DIR/BISECT_RUN" \
+		if sane_grep "first $BISECT_BAD commit could be any of" "$GIT_DIR/BISECT_RUN" \
 			>/dev/null
 		then
 			gettextln "bisect run cannot continue any more" >&2
@@ -480,7 +501,7 @@ exit code \$res from '\$command' is < 0 or >= 128" >&2
 			exit $res
 		fi
 
-		if sane_grep "is the first bad commit" "$GIT_DIR/BISECT_RUN" >/dev/null
+		if sane_grep "is the first $BISECT_BAD commit" "$GIT_DIR/BISECT_RUN" >/dev/null
 		then
 			gettextln "bisect run success"
 			exit 0;
@@ -494,18 +515,63 @@ bisect_log () {
 	cat "$GIT_DIR/BISECT_LOG"
 }
 
+get_terms () {
+	if test -s "$GIT_DIR/BISECT_TERMS"
+	then
+		BISECT_BAD="$(sed -n 1p "$GIT_DIR/BISECT_TERMS")"
+		BISECT_GOOD="$(sed -n 2p "$GIT_DIR/BISECT_TERMS")"
+	fi
+}
+
+check_and_set_terms () {
+	cmd="$1"
+	case "$cmd" in
+	bad|good|new|old)
+		if test -s "$GIT_DIR/BISECT_TERMS" -a "$cmd" != "$BISECT_BAD" -a "$cmd" != "$BISECT_GOOD"
+		then
+			die "$(eval_gettext "Invalid command : you're currently in a \$BISECT_BAD/\$BISECT_GOOD bisect.")"
+		fi
+		case "$cmd" in
+		bad|good)
+			if test ! -s "$GIT_DIR/BISECT_TERMS"
+			then
+				echo "bad" >"$GIT_DIR/BISECT_TERMS" &&
+				echo "good" >>"$GIT_DIR/BISECT_TERMS"
+			fi
+			BISECT_BAD="bad"
+			BISECT_GOOD="good" ;;
+		new|old)
+			if test ! -s "$GIT_DIR/BISECT_TERMS"
+			then
+				echo "new" >"$GIT_DIR/BISECT_TERMS" &&
+				echo "old" >>"$GIT_DIR/BISECT_TERMS"
+			fi
+			BISECT_BAD="new"
+			BISECT_GOOD="old" ;;
+		esac ;;
+	esac
+}
+
+bisect_voc () {
+	case "$1" in
+	bad) echo "bad|old" ;;
+	good) echo "good|new" ;;
+	esac
+}
+
 case "$#" in
 0)
 	usage ;;
 *)
 	cmd="$1"
+	get_terms
 	shift
 	case "$cmd" in
 	help)
 		git bisect -h ;;
 	start)
 		bisect_start "$@" ;;
-	bad|good)
+	bad|good|new|old)
 		bisect_state "$cmd" "$@" ;;
 	skip)
 		bisect_skip "$@" ;;
diff --git a/t/t6030-bisect-porcelain.sh b/t/t6030-bisect-porcelain.sh
index 06b4868..2163010 100755
--- a/t/t6030-bisect-porcelain.sh
+++ b/t/t6030-bisect-porcelain.sh
@@ -710,6 +710,8 @@ test_expect_success 'bisect: demonstrate identification of damage boundary' "
 		test \$rc = 0' &&
 	check_same BROKEN_HASH6 bisect/bad &&
 	git bisect reset
+	git checkout master
+
 "
 
 cat > expected.bisect-log <<EOF
@@ -759,4 +761,42 @@ test_expect_success '"git bisect bad HEAD" behaves as "git bisect bad"' '
 	git bisect reset
 '
 
+test_expect_success 'bisect starts with only one new' '
+	git bisect reset &&
+	git bisect start &&
+	git bisect new $HASH4 &&
+	git bisect next
+'
+test_expect_success 'bisect does not start with only one old' '
+	git bisect reset &&
+	git bisect start &&
+	git bisect old $HASH1 || return 1
+	test_must_fail git bisect next
+
+'
+
+test_expect_success 'bisect start with one new and old' '
+	git bisect reset &&
+	git bisect start &&
+	git bisect old $HASH1 &&
+	git bisect new $HASH4 &&
+	git bisect new &&
+	git bisect new >bisect_result &&
+	grep "$HASH2 is the first new commit" bisect_result &&
+	git bisect log > log_to_replay.txt &&
+	git bisect reset
+'
+
+test_expect_success 'bisect replay with old and new' '
+	git bisect replay log_to_replay.txt > bisect_result &&
+	grep "$HASH2 is the first new commit" bisect_result &&
+	git bisect reset
+'
+
+test_expect_success 'bisect cannot mix old/new and good/bad' '
+	git bisect start &&
+	git bisect bad $HASH4 &&
+	test_must_fail git bisect old $HASH1
+'
+
 test_done
-- 
2.4.1.173.gd47f443.dirty

[PATCH 2/3] bisect: use name_(bad|good) instead of bisect_(bad|good)

[Antoine Delaite]

From: Christian Couder <chriscool@tuxfamily.org>

Signed-off-by: Antoine Delaite <antoine.delaite@ensimag.grenoble-inp.fr>
---
 bisect.c | 35 +++++++++++++++++------------------
 1 file changed, 17 insertions(+), 18 deletions(-)

diff --git a/bisect.c b/bisect.c
index d6c19fd..68417bb 100644
--- a/bisect.c
+++ b/bisect.c
@@ -21,8 +21,8 @@ static const char *argv_checkout[] = {"checkout", "-q", NULL, "--", NULL};
 static const char *argv_show_branch[] = {"show-branch", NULL, NULL};
 static const char *argv_update_ref[] = {"update-ref", "--no-deref", "BISECT_HEAD", NULL, NULL};
 
-static const char *bisect_bad;
-static const char *bisect_good;
+static const char *name_bad;
+static const char *name_good;
 
 /* Remember to update object flag allocation in object.h */
 #define COUNTED		(1u<<16)
@@ -406,7 +406,7 @@ struct commit_list *find_bisection(struct commit_list *list,
 static int register_ref(const char *refname, const unsigned char *sha1,
 			int flags, void *cb_data)
 {
-	if (!strcmp(refname, bisect_bad)) {
+	if (!strcmp(refname, name_bad)) {
 		current_bad_oid = xmalloc(sizeof(*current_bad_oid));
 		hashcpy(current_bad_oid->hash, sha1);
 	} else if (starts_with(refname, "good-") ||
@@ -638,7 +638,7 @@ static void exit_if_skipped_commits(struct commit_list *tried,
 		return;
 
 	printf("There are only 'skip'ped commits left to test.\n"
-	       "The first %s commit could be any of:\n", bisect_bad);
+	       "The first %s commit could be any of:\n", name_bad);
 	print_commit_list(tried, "%s\n", "%s\n");
 	if (bad)
 		printf("%s\n", oid_to_hex(bad));
@@ -736,7 +736,7 @@ static void handle_bad_merge_base(void)
 	if (is_expected_rev(current_bad_oid)) {
 		char *bad_hex = oid_to_hex(current_bad_oid);
 		char *good_hex = join_sha1_array_hex(&good_revs, ' ');
-		if (!strcmp(bisect_bad,"bad")) {
+		if (!strcmp(name_bad,"bad")) {
 			fprintf(stderr, "The merge base %s is bad.\n"
 				"This means the bug has been fixed "
 				"between %s and [%s].\n",
@@ -753,8 +753,7 @@ static void handle_bad_merge_base(void)
 	fprintf(stderr, "Some %s revs are not ancestor of the %s rev.\n"
 		"git bisect cannot work properly in this case.\n"
 		"Maybe you mistook %s and %s revs?\n",
-		bisect_good, bisect_bad, bisect_good,
-		bisect_bad);
+		name_good, name_bad, name_good, name_bad);
 	exit(1);
 }
 
@@ -769,7 +768,7 @@ static void handle_skipped_merge_base(const unsigned char *mb)
 		"So we cannot be sure the first %s commit is "
 		"between %s and %s.\n"
 		"We continue anyway.",
-		bad_hex, good_hex, bisect_bad, mb_hex, bad_hex);
+		bad_hex, good_hex, name_bad, mb_hex, bad_hex);
 	free(good_hex);
 }
 
@@ -850,7 +849,7 @@ static void check_good_are_ancestors_of_bad(const char *prefix, int no_checkout)
 	int fd;
 
 	if (!current_bad_oid)
-		die("a %s revision is needed", bisect_bad);
+		die("a %s revision is needed", name_bad);
 
 	/* Check if file BISECT_ANCESTORS_OK exists. */
 	if (!stat(filename, &st) && S_ISREG(st.st_mode))
@@ -913,13 +912,13 @@ void read_bisect_terms(void)
 	FILE *fp = fopen(filename, "r");
 
 	if (!fp) {
-		bisect_bad = "bad";
-		bisect_good = "good";
+		name_bad = "bad";
+		name_good = "good";
 	} else {
 	strbuf_getline(&str, fp, '\n');
-	bisect_bad = strbuf_detach(&str, NULL);
+	name_bad = strbuf_detach(&str, NULL);
 	strbuf_getline(&str, fp, '\n');
-	bisect_good = strbuf_detach(&str, NULL);
+	name_good = strbuf_detach(&str, NULL);
 	}
 	strbuf_release(&str);
 	fclose(fp);
@@ -965,8 +964,8 @@ int bisect_next_all(const char *prefix, int no_checkout)
 
 		printf("%s was both %s and %s\n",
 		       oid_to_hex(current_bad_oid),
-		       bisect_good,
-		       bisect_bad);
+		       name_good,
+		       name_bad);
 		exit(1);
 	}
 
@@ -982,7 +981,7 @@ int bisect_next_all(const char *prefix, int no_checkout)
 	if (!hashcmp(bisect_rev, current_bad_oid->hash)) {
 		exit_if_skipped_commits(tried, current_bad_oid);
 		printf("%s is the first %s commit\n", bisect_rev_hex,
-			bisect_bad);
+			name_bad);
 		show_diff_tree(prefix, revs.commits->item);
 		/* This means the bisection process succeeded. */
 		exit(10);
@@ -994,8 +993,8 @@ int bisect_next_all(const char *prefix, int no_checkout)
 	       "(roughly %d step%s)\n", nr, (nr == 1 ? "" : "s"),
 	       steps, (steps == 1 ? "" : "s"));
 
-	free((char*)bisect_bad);
-	free((char*)bisect_good);
+	free((char*)name_bad);
+	free((char*)name_good);
 
 	return bisect_checkout(bisect_rev_hex, no_checkout);
 }
-- 
2.4.1.173.gd47f443.dirty

[PATCH 3/3] bisect: fix indentation

[Antoine Delaite]

From: Christian Couder <chriscool@tuxfamily.org>

Signed-off-by: Antoine Delaite <antoine.delaite@ensimag.grenoble-inp.fr>
---
 bisect.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/bisect.c b/bisect.c
index 68417bb..87a5f6d 100644
--- a/bisect.c
+++ b/bisect.c
@@ -915,10 +915,10 @@ void read_bisect_terms(void)
 		name_bad = "bad";
 		name_good = "good";
 	} else {
-	strbuf_getline(&str, fp, '\n');
-	name_bad = strbuf_detach(&str, NULL);
-	strbuf_getline(&str, fp, '\n');
-	name_good = strbuf_detach(&str, NULL);
+		strbuf_getline(&str, fp, '\n');
+		name_bad = strbuf_detach(&str, NULL);
+		strbuf_getline(&str, fp, '\n');
+		name_good = strbuf_detach(&str, NULL);
 	}
 	strbuf_release(&str);
 	fclose(fp);
-- 
2.4.1.173.gd47f443.dirty

Re: [WIP PATCH 1/3] git bisect old/new

[Matthieu Moy]

Antoine Delaite <antoine.delaite@ensimag.grenoble-inp.fr> writes:

> @@ -732,18 +736,25 @@ static void handle_bad_merge_base(void)
>  	if (is_expected_rev(current_bad_oid)) {
>  		char *bad_hex = oid_to_hex(current_bad_oid);
>  		char *good_hex = join_sha1_array_hex(&good_revs, ' ');
> -
> -		fprintf(stderr, "The merge base %s is bad.\n"
> -			"This means the bug has been fixed "
> -			"between %s and [%s].\n",
> -			bad_hex, bad_hex, good_hex);
> -
> +		if (!strcmp(bisect_bad,"bad")) {

space after comma.

> @@ -954,6 +994,9 @@ int bisect_next_all(const char *prefix, int no_checkout)
>  	       "(roughly %d step%s)\n", nr, (nr == 1 ? "" : "s"),
>  	       steps, (steps == 1 ? "" : "s"));
>  
> +	free((char*)bisect_bad);
> +	free((char*)bisect_good);

Already noted last time I think: these must not be freed as they are
pointing to static strings.

-- 
Matthieu Moy
http://www-verimag.imag.fr/~moy/

Re: [WIP PATCH 1/3] git bisect old/new

[Christian Couder]

On Thu, Jun 4, 2015 at 9:59 AM, Antoine Delaite
<antoine.delaite@ensimag.grenoble-inp.fr> wrote:
> From: Christian Couder <chriscool@tuxfamily.org>
>
> When not looking for a regression during a bisect but for a fix or a
> change in another given property, it can be confusing to use 'good'
> and 'bad'.
>
> This patch introduce `git bisect new` and `git bisect old` as an
> alternative to 'bad' and good': the commits which have the most
> recent version of the property must be marked as `new` and the ones
> with the older version as `old`.
>
> The output will be the first commit after the change in the property.
> During a new/old bisect session you cannot use bad/good commands and
> vice-versa.
>
> `git bisect replay` works fine for old/new bisect sessions.
>
> Some commands are still not available for old/new:
>
>      * git bisect start [<new> [<old>...]] is not possible: the
>        commits will be treated as bad and good.
>      * git rev-list --bisect does not treat the revs/bisect/new and
>        revs/bisect/old-SHA1 files.
>      * git bisect visualize seem to work partially: the tags are
>        displayed correctly but the tree is not limited to the bisect
>        section.
>
> Related discussions:
>
>         - http://thread.gmane.org/gmane.comp.version-control.git/86063
>                 introduced bisect fix unfixed to find fix.
>         - http://thread.gmane.org/gmane.comp.version-control.git/182398
>                 discussion around bisect yes/no or old/new.
>         - http://thread.gmane.org/gmane.comp.version-control.git/199758
>                 last discussion and reviews
>
> Signed-off-by: Antoine Delaite <antoine.delaite@ensimag.grenoble-inp.fr>
> Signed-off-by: Louis Stuber <stuberl@ensimag.grenoble-inp.fr>
> Signed-off-by: Valentin Duperray <Valentin.Duperray@ensimag.imag.fr>
> Signed-off-by: Franck Jonas <Franck.Jonas@ensimag.imag.fr>
> Signed-off-by: Lucien Kong <Lucien.Kong@ensimag.imag.fr>
> Signed-off-by: Thomas Nguy <Thomas.Nguy@ensimag.imag.fr>
> Signed-off-by: Huynh Khoi Nguyen Nguyen <Huynh-Khoi-Nguyen.Nguyen@ensimag.imag.fr>
> Signed-off-by: Matthieu Moy <Matthieu.Moy@grenoble-inp.fr>
> ---
> We took account of most of the "easy" reviews that were discuted two years ago.
> We hope we didn't missed any.
> http://thread.gmane.org/gmane.comp.version-control.git/199758
>
> We corrected various issues that were not reported:
> -one that caused a "fatal ... not a valid ref" at the end of the bisection.
> -the autostart was causing issues, the following lines were working :
> git bisect new HEAD
> git bisect bad HEAD
> git bisect good aGoodCommit
>
> The hard review which we were thinking on was the issue of the maintaining
> of old/new and allow easy support of new "tags" like yes/no in the future.
> I tried to remove the maximum of bad/good and old/new which were hard wrote in
> the code but I'm not completly satisfied. This patch is clearly a v1.

Thanks for working on this. Here are some suggestions that I should
probably have told you before, but didn't:

- Take ownership of all the patches.
- Patch 3/3 renames some variables in bisect.c, do the same thing in
git-bisect.sh for consistency.
- Squash all the patches together.
- Try to find a way to break down the resulting patch into a logical
patch series which adds tests at each logical step. This might be
difficult. You might want to add features to git bisect--helper first
for example, then test those features, then add features to git bisect
and then test those features.

Best,
Christian.

> We're currently working on:
>
> * rebasing the history of the patch
> * git rev-list --bisect does not treat the revs/bisect/new and
> revs/bisect/old-SHA1 files.
> * git bisect visualize seem to work partially: the tags are displayed
> correctly but the tree is not limited to the bisect section.
> * adding tests about old/new
>
> Some other problems that might also be considerred later :
> * change/add valid terms (e.g "unfixed/fixed" instead of "old/new")
> *
> * git bisect start [<new> [<old>...]] is not possible: the commits
> will be treated as bad and good.
>

Re: [WIP PATCH 1/3] git bisect old/new

[Junio C Hamano]

Antoine Delaite <antoine.delaite@ensimag.grenoble-inp.fr> writes:

> From: Christian Couder <chriscool@tuxfamily.org>
>
> When not looking for a regression during a bisect but for a fix or a
> change in another given property, it can be confusing to use 'good'
> and 'bad'.
>
> This patch introduce `git bisect new` and `git bisect old` as an
> alternative to 'bad' and good': the commits which have the most
> recent version of the property must be marked as `new` and the ones
> with the older version as `old`.

The phrase "the most recent version of" invites an unnecessary
confusion.  "git bisect" is a tool to find a single bit flip and if
the behaviour changed twice in the history from A to B to C, you
cannot look for the transition between A to B or B to C.  You need
to say "I classify behaviour B and C to be both good (new) and I
know it used to have behaviour A which was bad (old)".

    You can mark the commits with the "new" property as "new", and
    the "old" property as "old"; "good" being "new" and "bad" being
    "old" becomes a mere special case of this.  The "new" property
    in the traditional bisection is "commit has the bug we are
    hunting", while "old" is "commit lacks that bug".

> diff --git a/Documentation/git-bisect.txt b/Documentation/git-bisect.txt
> index 4cb52a7..12c7711 100644
> --- a/Documentation/git-bisect.txt
> +++ b/Documentation/git-bisect.txt
> ...
> @@ -104,6 +104,33 @@ For example, `git bisect reset HEAD` will leave you on the current
>  bisection commit and avoid switching commits at all, while `git bisect
>  reset bisect/bad` will check out the first bad revision.
>  
> +
> +Alternative terms: bisect new and bisect old
> +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> +
> +If you are not at ease with the terms "bad" and "good", perhaps
> +because you are looking for the commit that introduced a fix, you can
> +alternatively use "new" and "old" instead.
> +But note that you cannot mix "bad" and good" with "new" and "old".

There is a dq missing somewhere on this line.

> +
> +------------------------------------------------
> +git bisect new [<rev>]
> +------------------------------------------------
> +
> +Marks the commit as new, which means the version is fixed.

I am not sure ", which means the version is fixed." is a good idea.

The whole point of introducing "old" vs "new", the reason why we may
want to do this patch series, is to reduce confusion by removing the
value judgement associated with "good" vs "bad".  That is what made
the bisect confusing when the old ones were bad and new ones were
good.  Saying "fixed" implicitly contrasts it with "broken", and
introduces the value judgement on the states again.

	Side note: yes, if the reader is careful, "fixed" needs to
	have previous states to be "broken", so in that sense,
	"fixed" can be read about time-sequence and not about value
	judgement.  But let's try to be understandable by even
	casual readers.

We would instead want to emphasize that what we are judging is not
values but time sequence.  You would want to say "It used to be X
but it no longer is X", without saying if X is a good thing or not,
e.g.

	Marks the commit as new, e.g. "the bug is no longer there",
        if you are looking for a commit that fixed a bug, or "the
        feature that used to work is now broken at this point", if
        you are looking for a commit that introduced a bug.

> +------------------------------------------------
> +git bisect old [<rev>...]
> +------------------------------------------------
> +
> +Marks the commit as old, which means the bug is present.

This is much worse than the previous one. Unless you force the
reader to _assume_ that you are hunting for a fix, "bug is present"
can mean "bug is still present", or "bug was introduced somewhere
along the line and now it is there".  And a casual mention of
"perhaps because you are looking for a fix" at the beginning of the
section is not strong enough hint that these examples are _only_
about "hunting for bugfix".

I'd stop here for now, but a casual skimming told me that the same
issue exists throughout the remainder of the doc.

Thanks.