#!/bin/sh

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 [--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 skip [(<rev>|<range>)...]
        mark <rev>... untestable revisions.
git bisect next
        find next bisection to test and check it out.
git bisect reset [<commit>]
        finish bisection search and go back to commit.
git bisect visualize
        show bisect status in gitk.
git bisect replay <logfile>
        replay bisection log.
git bisect log
        show bisect log.
git bisect run <cmd>...
        use <cmd>... to automatically bisect.

Please use "git help bisect" to get the full man page.'

OPTIONS_SPEC=
. git-sh-setup
. git-sh-i18n

_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_head()
{
        if test -f "$GIT_DIR/BISECT_HEAD"
        then
                echo BISECT_HEAD
        else
                echo HEAD
        fi
}

bisect_autostart() {
        test -s "$GIT_DIR/BISECT_START" || {
                gettextln "You need to start by \"git bisect start\"" >&2
                if test -t 0
                then
                        # TRANSLATORS: Make sure to include [Y] and [n] in your
                        # translation. The program will only accept English input
                        # at this point.
                        gettext "Do you want me to do it for you [Y/n]? " >&2
                        read yesno
                        case "$yesno" in
                        [Nn]*)
                                exit ;;
                        esac
                        bisect_start
                else
                        exit 1
                fi
        }
}

bisect_start() {
        #
        # Check for one bad and then some good revisions.
        #
        has_double_dash=0
        for arg; do
                case "$arg" in --) has_double_dash=1; break ;; esac
        done
        orig_args=$(git rev-parse --sq-quote "$@")
        bad_seen=0
        eval=''
        if test "z$(git rev-parse --is-bare-repository)" != zfalse
        then
                mode=--no-checkout
        else
                mode=''
        fi
        while [ $# -gt 0 ]; do
                arg="$1"
                case "$arg" in
                --)
                        shift
                        break
                ;;
                --no-checkout)
                        mode=--no-checkout
                        shift ;;
                --*)
                        die "$(eval_gettext "unrecognised option: '\$arg'")" ;;
                *)
                        rev=$(git rev-parse -q --verify "$arg^{commit}") || {
                                test $has_double_dash -eq 1 &&
                                die "$(eval_gettext "'\$arg' does not appear to be a valid revision")"
                                break
                        }
                        case $bad_seen in
                        0) state='bad' ; bad_seen=1 ;;
                        *) state='good' ;;
                        esac
                        eval="$eval bisect_write '$state' '$rev' 'nolog' &&"
                        shift
                        ;;
                esac
        done

        #
        # Verify HEAD.
        #
        head=$(GIT_DIR="$GIT_DIR" git symbolic-ref -q HEAD) ||
        head=$(GIT_DIR="$GIT_DIR" git rev-parse --verify HEAD) ||
        die "$(gettext "Bad HEAD - I need a HEAD")"

        #
        # Check if we are bisecting.
        #
        start_head=''
        if test -s "$GIT_DIR/BISECT_START"
        then
                # Reset to the rev from where we started.
                start_head=$(cat "$GIT_DIR/BISECT_START")
                if test "z$mode" != "z--no-checkout"
                then
                        git checkout "$start_head" -- ||
                        die "$(eval_gettext "Checking out '\$start_head' failed. Try 'git bisect reset <validbranch>'.")"
                fi
        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 "$GIT_DIR/head-name" ] &&
                                die "$(gettext "won't bisect on seeked tree")"
                        start_head="${head#refs/heads/}"
                        ;;
                *)
                        die "$(gettext "Bad HEAD - strange symbolic ref")"
                        ;;
                esac
        fi

        #
        # Get rid of any old bisect state.
        #
        bisect_clean_state || exit

        #
        # 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" && {
                test "z$mode" != "z--no-checkout" ||
                git update-ref --no-deref BISECT_HEAD "$start_head"
        } &&
        git rev-parse --sq-quote "$@" >"$GIT_DIR/BISECT_NAMES" &&
        eval "$eval true" &&
        echo "git bisect start$orig_args" >>"$GIT_DIR/BISECT_LOG" || exit
        #
        # Check if we can proceed to the next bisect state.
        #
        bisect_auto_next

        trap '-' 0
}

bisect_write() {
        state="$1"
        rev="$2"
        nolog="$3"
        case "$state" in
                bad)            tag="$state" ;;
                good|skip)      tag="$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"
        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")
}

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 "$(eval_gettext "Bad rev input: \$arg")" ;;
                *)
                        revs=$(git rev-parse --sq-quote "$arg") ;;
                esac
                all="$all $revs"
        done
        eval bisect_state 'skip' $all
}

bisect_state() {
        bisect_autostart
        state=$1
        case "$#,$state" in
        0,*)
                die "$(gettext "Please call 'bisect_state' with at least one argument.")" ;;
        1,bad|1,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)
                shift
                eval=''
                for rev in "$@"
                do
                        sha=$(git rev-parse --verify "$rev^{commit}") ||
                                die "$(eval_gettext "Bad rev input: \$rev")"
                        eval="$eval bisect_write '$state' '$sha'; "
                done
                eval "$eval"
                check_expected_revs "$@" ;;
        *,bad)
                die "$(gettext "'git bisect bad' can take only one argument.")" ;;
        *)
                usage ;;
        esac
        bisect_auto_next
}

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

        case "$missing_good,$missing_bad,$1" in
        ,,*)
                : have both good and bad - ok
                ;;
        *,)
                # do not have both but not asked to fail - just report.
                false
                ;;
        t,,good)
                # have bad but not good.  we could bisect although
                # this is less optimum.
                gettextln "Warning: bisecting only with a bad commit." >&2
                if test -t 0
                then
                        # TRANSLATORS: Make sure to include [Y] and [n] in your
                        # translation. The program will only accept English input
                        # at this point.
                        gettext "Are you sure [Y/n]? " >&2
                        read yesno
                        case "$yesno" in [Nn]*) exit 1 ;; esac
                fi
                : bisect without good...
                ;;
        *)

                if test -s "$GIT_DIR/BISECT_START"
                then
                        gettextln "You need to give me at least one good and one bad revisions.
(You can use \"git bisect bad\" and \"git bisect 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 revisions.
(You can use \"git bisect bad\" and \"git bisect good\" for that.)" >&2
                fi
                exit 1 ;;
        esac
}

bisect_auto_next() {
        bisect_next_check && bisect_next || :
}

bisect_next() {
        case "$#" in 0) ;; *) usage ;; esac
        bisect_autostart
        bisect_next_check good

        # Perform all bisection computation, display and checkout
        git bisect--helper --next-all $(test -f "$GIT_DIR/BISECT_HEAD" && echo --no-checkout)
        res=$?

        # 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_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 $good_revs)
                do
                        skipped_commit=$(git show-branch $skipped)
                        echo "# possible first bad commit: $skipped_commit" >>"$GIT_DIR/BISECT_LOG"
                done
                exit $res
        fi

        # Check for an error in the bisection process
        test $res -ne 0 && exit $res

        return 0
}

bisect_visualize() {
        bisect_next_check fail

        if test $# = 0
        then
                if test -n "${DISPLAY+set}${SESSIONNAME+set}${MSYSTEM+set}${SECURITYSESSIONID+set}" &&
                        type gitk >/dev/null 2>&1
                then
                        set gitk
                else
                        set git log
                fi
        else
                case "$1" in
                git*|tig) ;;
                -*)     set git log "$@" ;;
                *)      set git "$@" ;;
                esac
        fi

        eval '"$@"' --bisect -- $(cat "$GIT_DIR/BISECT_NAMES")
}

bisect_reset() {
        test -s "$GIT_DIR/BISECT_START" || {
                gettextln "We are not bisecting."
                return
        }
        case "$#" in
        0) branch=$(cat "$GIT_DIR/BISECT_START") ;;
        1) git rev-parse --quiet --verify "$1^{commit}" > /dev/null || {
                        invalid="$1"
                        die "$(eval_gettext "'\$invalid' is not a valid commit")"
                }
                branch="$1" ;;
        *)
                usage ;;
        esac

        if ! test -f "$GIT_DIR/BISECT_HEAD" && ! git checkout "$branch" --
        then
                die "$(eval_gettext "Could not check out original HEAD '\$branch'.
Try 'git bisect reset <commit>'.")"
        fi
        bisect_clean_state
}

bisect_clean_state() {
        # There may be some refs packed during bisection.
        git for-each-ref --format='%(refname) %(objectname)' refs/bisect/\* |
        while read ref hash
        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" &&
        # Cleanup head-name if it got left by an old version of git-bisect
        rm -f "$GIT_DIR/head-name" &&
        git update-ref -d --no-deref BISECT_HEAD &&
        # clean up BISECT_START last
        rm -f "$GIT_DIR/BISECT_START"
}

bisect_replay () {
        file="$1"
        test "$#" -eq 1 || die "$(gettext "No logfile given")"
        test -r "$file" || die "$(eval_gettext "cannot read \$file for replaying")"
        bisect_reset
        while read git bisect command rev
        do
                test "$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 $rev"
                        eval "$cmd" ;;
                good|bad|skip)
                        bisect_write "$command" "$rev" ;;
                *)
                        die "$(gettext "?? what are you talking about?")" ;;
                esac
        done <"$file"
        bisect_auto_next
}

bisect_run () {
        bisect_next_check fail

        while true
        do
                command="$@"
                eval_gettextln "running \$command"
                "$@"
                res=$?

                # Check for really bad run error.
                if [ $res -lt 0 -o $res -ge 128 ]
                then
                        eval_gettextln "bisect run failed:
exit code \$res from '\$command' is < 0 or >= 128" >&2
                        exit $res
                fi

                # Find current state depending on run success or failure.
                # A special exit code of 125 means cannot test.
                if [ $res -eq 125 ]
                then
                        state='skip'
                elif [ $res -gt 0 ]
                then
                        state='bad'
                else
                        state='good'
                fi

                # We have to use a subshell because "bisect_state" can exit.
                ( bisect_state $state > "$GIT_DIR/BISECT_RUN" )
                res=$?

                cat "$GIT_DIR/BISECT_RUN"

                if sane_grep "first bad commit could be any of" "$GIT_DIR/BISECT_RUN" \
                        > /dev/null
                then
                        gettextln "bisect run cannot continue any more" >&2
                        exit $res
                fi

                if [ $res -ne 0 ]
                then
                        eval_gettextln "bisect run failed:
'bisect_state \$state' exited with error code \$res" >&2
                        exit $res
                fi

                if sane_grep "is the first bad commit" "$GIT_DIR/BISECT_RUN" > /dev/null
                then
                        gettextln "bisect run success"
                        exit 0;
                fi

        done
}

bisect_log () {
        test -s "$GIT_DIR/BISECT_LOG" || die "$(gettext "We are not bisecting.")"
        cat "$GIT_DIR/BISECT_LOG"
}

case "$#" in
0)
        usage ;;
*)
        cmd="$1"
        shift
        case "$cmd" in
        help)
                git bisect -h ;;
        start)
                bisect_start "$@" ;;
        bad|good)
                bisect_state "$cmd" "$@" ;;
        skip)
                bisect_skip "$@" ;;
        next)
                # Not sure we want "next" at the UI level anymore.
                bisect_next "$@" ;;
        visualize|view)
                bisect_visualize "$@" ;;
        reset)
                bisect_reset "$@" ;;
        replay)
                bisect_replay "$@" ;;
        log)
                bisect_log ;;
        run)
                bisect_run "$@" ;;
        *)
                usage ;;
        esac
esac