rebase -i: learn to rebase root commit
[gitweb.git] / git-bisect.sh
index b1800edaf713f972131431fcd26b5e7f64f089fc..17a35f6adc79480d0533a4ff98b2817c836a7e78 100755 (executable)
@@ -1,13 +1,15 @@
 #!/bin/sh
 
-USAGE='[start|bad|good|skip|next|reset|visualize|replay|log|run]'
-LONG_USAGE='git bisect start [<bad> [<good>...]] [--] [<pathspec>...]
+USAGE='[help|start|bad|good|skip|next|reset|visualize|replay|log|run]'
+LONG_USAGE='git bisect help
+        print this long help message.
+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 skip [<rev>...]
+git bisect skip [(<rev>|<range>)...]
         mark <rev>... untestable revisions.
 git bisect next
         find next bisection to test and check it out.
@@ -20,7 +22,9 @@ git bisect replay <logfile>
 git bisect log
         show bisect log.
 git bisect run <cmd>...
-        use <cmd>... to automatically bisect.'
+        use <cmd>... to automatically bisect.
+
+Please use "git help bisect" to get the full man page.'
 
 OPTIONS_SPEC=
 . git-sh-setup
@@ -40,7 +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
@@ -59,42 +63,42 @@ bisect_autostart() {
 
 bisect_start() {
        #
-       # Verify HEAD. If we were bisecting before this, reset to the
-       # top-of-line master first!
+       # Verify HEAD.
        #
        head=$(GIT_DIR="$GIT_DIR" git symbolic-ref -q HEAD) ||
        head=$(GIT_DIR="$GIT_DIR" git rev-parse --verify HEAD) ||
        die "Bad HEAD - I need a HEAD"
+
        #
-       # Check that we either already have BISECT_START, or that the
-       # branches bisect, new-bisect don't exist, to not override them.
+       # Check if we are bisecting.
        #
-       test -s "$GIT_DIR/BISECT_START" ||
-               if git show-ref --verify -q refs/heads/bisect ||
-                   git show-ref --verify -q refs/heads/new-bisect; then
-                       die 'The branches "bisect" and "new-bisect" must not exist.'
-               fi
        start_head=''
-       case "$head" in
-       refs/heads/bisect)
-               branch=`cat "$GIT_DIR/BISECT_START"`
-               git checkout $branch || exit
-               ;;
-       refs/heads/*|$_x40)
-               # This error message should only be triggered by cogito usage,
-               # and cogito users should understand it relates to cg-seek.
-               [ -s "$GIT_DIR/head-name" ] && die "won't bisect on seeked tree"
-               start_head="${head#refs/heads/}"
-               ;;
-       *)
-               die "Bad HEAD - strange symbolic ref"
-               ;;
-       esac
+       if test -s "$GIT_DIR/BISECT_START"
+       then
+               # Reset to the rev from where we started.
+               start_head=$(cat "$GIT_DIR/BISECT_START")
+               git checkout "$start_head" || exit
+       else
+               # Get rev from where we start.
+               case "$head" in
+               refs/heads/*|$_x40)
+                       # This error message should only be triggered by
+                       # cogito usage, and cogito users should understand
+                       # it relates to cg-seek.
+                       [ -s "$GIT_DIR/head-name" ] &&
+                               die "won't bisect on seeked tree"
+                       start_head="${head#refs/heads/}"
+                       ;;
+               *)
+                       die "Bad HEAD - strange symbolic ref"
+                       ;;
+               esac
+       fi
 
        #
-       # Get rid of any old bisect state
+       # Get rid of any old bisect state.
        #
-       bisect_clean_state
+       bisect_clean_state || exit
 
        #
        # Check for one bad and then some good revisions.
@@ -114,7 +118,7 @@ bisect_start() {
                break
                ;;
            *)
-               rev=$(git rev-parse --verify "$arg^{commit}" 2>/dev/null) || {
+               rev=$(git rev-parse -q --verify "$arg^{commit}") || {
                    test $has_double_dash -eq 1 &&
                        die "'$arg' does not appear to be a valid revision"
                    break
@@ -129,11 +133,29 @@ bisect_start() {
            esac
        done
 
-       sq "$@" >"$GIT_DIR/BISECT_NAMES"
-       test -n "$start_head" && echo "$start_head" >"$GIT_DIR/BISECT_START"
-       eval "$eval"
-       echo "git-bisect start$orig_args" >>"$GIT_DIR/BISECT_LOG"
+       #
+       # Change state.
+       # In case of mistaken revs or checkout error, or signals received,
+       # "bisect_auto_next" below may exit or misbehave.
+       # We have to trap this to be able to clean up using
+       # "bisect_clean_state".
+       #
+       trap 'bisect_clean_state' 0
+       trap 'exit 255' 1 2 3 15
+
+       #
+       # Write new start state.
+       #
+       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
+       #
+       # Check if we can proceed to the next bisect state.
+       #
        bisect_auto_next
+
+       trap '-' 0
 }
 
 bisect_write() {
@@ -145,9 +167,43 @@ bisect_write() {
                good|skip)      tag="$state"-"$rev" ;;
                *)              die "Bad bisect_write argument: $state" ;;
        esac
-       git update-ref "refs/bisect/$tag" "$rev"
+       git update-ref "refs/bisect/$tag" "$rev" || exit
        echo "# $state: $(git show-branch $rev)" >>"$GIT_DIR/BISECT_LOG"
-       test -z "$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_skip() {
+        all=''
+       for arg in "$@"
+       do
+           case "$arg" in
+            *..*)
+                revs=$(git rev-list "$arg") || die "Bad rev input: $arg" ;;
+            *)
+                revs=$(sq "$arg") ;;
+           esac
+            all="$all $revs"
+        done
+        eval bisect_state 'skip' $all
 }
 
 bisect_state() {
@@ -159,7 +215,8 @@ 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=''
@@ -169,7 +226,8 @@ bisect_state() {
                                die "Bad rev input: $rev"
                        eval="$eval bisect_write '$state' '$sha'; "
                done
-               eval "$eval" ;;
+               eval "$eval"
+               check_expected_revs "$@" ;;
        *,bad)
                die "'git bisect bad' can take only one argument." ;;
        *)
@@ -198,13 +256,14 @@ bisect_next_check() {
                if test -t 0
                then
                        printf >&2 'Are you sure [Y/n]? '
-                       case "$(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 '
                }
@@ -220,33 +279,18 @@ 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.
@@ -309,20 +353,133 @@ 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" "$skip") &&
@@ -343,11 +500,7 @@ bisect_next() {
        # commit is also a "skip" commit (see above).
        exit_if_skipped_commits "$bisect_rev"
 
-       echo "Bisecting: $bisect_nr revisions left to test after this"
-       git branch -D new-bisect 2> /dev/null
-       git checkout -q -b new-bisect "$bisect_rev" || exit
-       git branch -M new-bisect bisect
-       git show-branch "$bisect_rev"
+       bisect_checkout "$bisect_rev" "$bisect_nr revisions left to test after this"
 }
 
 bisect_visualize() {
@@ -372,48 +525,49 @@ 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="$1" ;;
        *)
            usage ;;
        esac
-       if git checkout "$branch"; then
-               # Cleanup head-name if it got left by an old version of git-bisect
-               rm -f "$GIT_DIR/head-name"
-               rm -f "$GIT_DIR/BISECT_START"
-               bisect_clean_state
-       fi
+       git checkout "$branch" && bisect_clean_state
 }
 
 bisect_clean_state() {
        # There may be some refs packed during bisection.
-       git for-each-ref --format='%(refname) %(objectname)' refs/bisect/\* refs/heads/bisect |
+       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_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/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 $rev"
@@ -487,10 +641,14 @@ case "$#" in
     cmd="$1"
     shift
     case "$cmd" in
+    help)
+        git bisect -h ;;
     start)
         bisect_start "$@" ;;
-    bad|good|skip)
+    bad|good)
         bisect_state "$cmd" "$@" ;;
+    skip)
+        bisect_skip "$@" ;;
     next)
         # Not sure we want "next" at the UI level anymore.
         bisect_next "$@" ;;