Update draft release notes to 1.6.1
[gitweb.git] / git-bisect.sh
index 97ac600873ebd0dff6310071343403a41a867b8a..79de7017e88b746971f5a730b8615290bba2890d 100755 (executable)
@@ -172,6 +172,25 @@ bisect_write() {
        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() {
        bisect_autostart
        state=$1
@@ -181,7 +200,8 @@ bisect_state() {
        1,bad|1,good|1,skip)
                rev=$(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." ;;
        *)
@@ -243,33 +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.
@@ -332,20 +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=$(git for-each-ref --format='%(objectname)' \
-               "refs/bisect/skip-*" | tr '\012' ' ') || exit
+               "refs/bisect/skip-*" | tr '\012' ' ') &&
+
+       # Maybe some merge bases must be tested first
+       check_good_are_ancestors_of_bad "$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" "$skip") &&
@@ -366,9 +485,7 @@ bisect_next() {
        # commit is also a "skip" commit (see above).
        exit_if_skipped_commits "$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() {
@@ -415,6 +532,8 @@ bisect_clean_state() {
        do
                git update-ref -d $ref $hash || exit
        done
+       rm -f "$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" &&