Hi all,
Following proposed patch try to implement reverse mode for git bisect.
The git bisect command is written in the regression-finding in mind. IOW
it expects the good commit is older than the later one, which caused a
regression.
However common usage for (at least) package maintainer is not to find a
regression and fix it. The main task it to identify a bugfix!. In this
case git bisect is still helpfull as it reduces a time a lot, but user
needs to exchange the good<->bad in his mind, which is confusing and in
case there are delays in the work, it's trivial to forgot that I have to
type git bisect good, when I'm in the bad revision.
This simple patch try to address the problem of poor package
maintainer's brain and introduces --reverse argument for the git bisect
start command.
In this mode, bisect internally exchange the behavior of good/bad
itself, so there's no need to do it manually. I did some basic testing
and
git bisect start --reverse HEAD~999 HEAD
git bisect good/bad/skip/run
really works well, allowing user to identify a first good commit instead
of the first bad one. I did not test other commands like visualize or
replay.
What do you think about it? Do you see other problems I'm not aware of?
---
bisect.c | 2 +-
git-bisect.sh | 49 ++++++++++++++++++++++++++++++++++++++++++++-----
2 files changed, 45 insertions(+), 6 deletions(-)
diff --git a/bisect.c b/bisect.c
index c7b7d79..33aaeaa 100644
--- a/bisect.c
+++ b/bisect.c
@@ -768,7 +768,7 @@ static void handle_bad_merge_base(void)
fprintf(stderr, "Some good revs are not ancestor of the bad rev.\n"
"git bisect cannot work properly in this case.\n"
- "Maybe you mistake good and bad revs?\n");
+ "Try --reverse to switch the bisect logic.\n");
exit(1);
}
diff --git a/git-bisect.sh b/git-bisect.sh
index 2524060..5c95f25 100755
--- a/git-bisect.sh
+++ b/git-bisect.sh
@@ -33,6 +33,25 @@ 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_reverse_mode() {
+ test -f "$GIT_DIR/BISECT_REVERSE"
+}
+
+bisect_reverse_state() {
+
+ if bisect_reverse_mode; then
+ if test "$1" = "good"; then
+ echo "bad"
+ return 0
+ elif test "$1" = "bad"; then
+ echo "good"
+ return 0
+ fi
+ fi
+
+ echo $1
+}
+
bisect_head()
{
if test -f "$GIT_DIR/BISECT_HEAD"
@@ -69,6 +88,11 @@ bisect_start() {
# Check for one bad and then some good revisions.
#
has_double_dash=0
+ #
+ # Exchange the internal meainng of good/bad allowing bisect to find
+ # a commit fixing a bug, not "only" the one causes a regression
+ #
+ reverse_mode=1
for arg; do
case "$arg" in --) has_double_dash=1; break ;; esac
done
@@ -91,6 +115,9 @@ bisect_start() {
--no-checkout)
mode=--no-checkout
shift ;;
+ --reverse)
+ reverse_mode=0
+ shift ;;
--*)
die "$(eval_gettext "unrecognised option: '\$arg'")" ;;
*)
@@ -99,10 +126,17 @@ bisect_start() {
die "$(eval_gettext "'\$arg' does not appear to be a valid revision")"
break
}
- case $bad_seen in
- 0) state='bad' ; bad_seen=1 ;;
- *) state='good' ;;
- esac
+ if test $reverse_mode -ne 0; then
+ case $bad_seen in
+ 0) state='bad' ; bad_seen=1 ;;
+ *) state='good' ;;
+ esac
+ else
+ case $bad_seen in
+ 0) state='good' ; bad_seen=1 ;;
+ *) state='bad' ;;
+ esac
+ fi
eval="$eval bisect_write '$state' '$rev' 'nolog' &&"
shift
;;
@@ -170,6 +204,9 @@ bisect_start() {
git rev-parse --sq-quote "$@" >"$GIT_DIR/BISECT_NAMES" &&
eval "$eval true" &&
echo "git bisect start$orig_args" >>"$GIT_DIR/BISECT_LOG" || exit
+ if test $reverse_mode -eq 0; then
+ /bin/touch "$GIT_DIR/BISECT_REVERSE" || exit
+ fi
#
# Check if we can proceed to the next bisect state.
#
@@ -225,7 +262,7 @@ bisect_skip() {
bisect_state() {
bisect_autostart
- state=$1
+ state=$(bisect_reverse_state $1)
case "$#,$state" in
0,*)
die "$(gettext "Please call 'bisect_state' with at least one argument.")" ;;
@@ -377,6 +414,7 @@ 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_REVERSE" &&
# 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 &&
@@ -402,6 +440,7 @@ bisect_replay () {
cmd="bisect_start $rev"
eval "$cmd" ;;
good|bad|skip)
+ command=$(bisect_reverse_state $1)
bisect_write "$command" "$rev" ;;
*)
die "$(gettext "?? what are you talking about?")" ;;
--
1.7.6.3
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