#!/bin/sh

USAGE='[help|start|bad|good|new|old|terms|skip|next|reset|visualize|replay|log|run]'
LONG_USAGE='git bisect help
        print this long help message.
git bisect start [--term-{old,good}=<term> --term-{new,bad}=<term>]
                 [--no-checkout] [<bad> [<good>...]] [--] [<pathspec>...]
        reset bisect state and start bisection.
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 terms [--term-good | --term-bad]
        show the terms used for old and new commits (default: bad, good)
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

_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"
TERM_BAD=bad
TERM_GOOD=good

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 "$@")
        bad_seen=0
        eval=''
        must_write_terms=0
        revs=''
        if test "z$(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 ;;
                --term-good|--term-old)
                        shift
                        must_write_terms=1
                        TERM_GOOD=$1
                        shift ;;
                --term-good=*|--term-old=*)
                        must_write_terms=1
                        TERM_GOOD=${1#*=}
                        shift ;;
                --term-bad|--term-new)
                        shift
                        must_write_terms=1
                        TERM_BAD=$1
                        shift ;;
                --term-bad=*|--term-new=*)
                        must_write_terms=1
                        TERM_BAD=${1#*=}
                        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
                        }
                        revs="$revs $rev"
                        shift
                        ;;
                esac
        done

        for rev in $revs
        do
                # The user ran "git bisect start <sha1>
                # <sha1>", hence did not explicitly specify
                # the terms, but we are already starting to
                # set references named with the default terms,
                # and won't be able to change afterwards.
                must_write_terms=1

                case $bad_seen in
                0) state=$TERM_BAD ; bad_seen=1 ;;
                *) state=$TERM_GOOD ;;
                esac
                eval="$eval bisect_write '$state' '$rev' 'nolog' &&"
        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 <valid-branch>'.")"
                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 cg-seek'ed 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" &&
        if test $must_write_terms -eq 1
        then
                write_terms "$TERM_BAD" "$TERM_GOOD"
        fi &&
        echo "git bisect start$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
                "$TERM_BAD")
                        tag="$state" ;;
                "$TERM_GOOD"|skip)
                        tag="$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
        check_and_set_terms $state
        case "$#,$state" in
        0,*)
                die "Please call 'bisect_state' with at least one argument." ;;
        1,"$TERM_BAD"|1,"$TERM_GOOD"|1,skip)
                bisected_head=$(bisect_head)
                rev=$(git rev-parse --verify "$bisected_head") ||
                        die "$(eval_gettext "Bad rev input: \$bisected_head")"
                bisect_write "$state" "$rev"
                check_expected_revs "$rev" ;;
        2,"$TERM_BAD"|*,"$TERM_GOOD"|*,skip)
                shift
                hash_list=''
                for rev in "$@"
                do
                        sha=$(git rev-parse --verify "$rev^{commit}") ||
                                die "$(eval_gettext "Bad rev input: \$rev")"
                        hash_list="$hash_list $sha"
                done
                for rev in $hash_list
                do
                        bisect_write "$state" "$rev"
                done
                check_expected_revs $hash_list ;;
        *,"$TERM_BAD")
                die "$(eval_gettext "'git bisect \$TERM_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/$TERM_BAD || missing_bad=t
        test -n "$(git for-each-ref "refs/bisect/$TERM_GOOD-*")" || missing_good=t

        case "$missing_good,$missing_bad,$1" in
        ,,*)
                : have both $TERM_GOOD and $TERM_BAD - ok
                ;;
        *,)
                # do not have both but not asked to fail - just report.
                false
                ;;
        t,,"$TERM_GOOD")
                # have bad (or new) but not good (or old).  we could bisect although
                # this is less optimum.
                eval_gettextln "Warning: bisecting only with a \$TERM_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 $TERM_GOOD...
                ;;
        *)
                bad_syn=$(bisect_voc bad)
                good_syn=$(bisect_voc good)
                if test -s "$GIT_DIR/BISECT_START"
                then

                        eval_gettextln "You need to give me at least one \$bad_syn and one \$good_syn revision.
(You can use \"git bisect \$bad_syn\" and \"git bisect \$good_syn\" for that.)" >&2
                else
                        eval_gettextln "You need to start by \"git bisect start\".
You then need to give me at least one \$good_syn and one \$bad_syn revision.
(You can use \"git bisect \$bad_syn\" and \"git bisect \$good_syn\" 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 $TERM_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/$TERM_BAD)
                bad_commit=$(git show-branch $bad_rev)
                echo "# first $TERM_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=$(git for-each-ref --format="%(objectname)" "refs/bisect/$TERM_GOOD-*")
                for skipped in $(git rev-list refs/bisect/$TERM_BAD --not $good_revs)
                do
                        skipped_commit=$(git show-branch $skipped)
                        echo "# possible first $TERM_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" &&
        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 &&
        # 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 $bisect" = "git bisect" || test "$git" = "git-bisect" || continue
                if test "$git" = "git-bisect"
                then
                        rev="$command"
                        command="$bisect"
                fi
                get_terms
                check_and_set_terms "$command"
                case "$command" in
                start)
                        cmd="bisect_start $rev"
                        eval "$cmd" ;;
                "$TERM_GOOD"|"$TERM_BAD"|skip)
                        bisect_write "$command" "$rev" ;;
                terms)
                        bisect_terms $rev ;;
                *)
                        die "$(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 [ $res -gt 0 ]
                then
                        state="$TERM_BAD"
                else
                        state="$TERM_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 $TERM_BAD commit could be any of" "$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 $TERM_BAD commit" "$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"
}

get_terms () {
        if test -s "$GIT_DIR/BISECT_TERMS"
        then
                {
                read TERM_BAD
                read TERM_GOOD
                } <"$GIT_DIR/BISECT_TERMS"
        fi
}

write_terms () {
        TERM_BAD=$1
        TERM_GOOD=$2
        if test "$TERM_BAD" = "$TERM_GOOD"
        then
                die "$(gettext "please use two different terms")"
        fi
        check_term_format "$TERM_BAD" bad
        check_term_format "$TERM_GOOD" good
        printf '%s\n%s\n' "$TERM_BAD" "$TERM_GOOD" >"$GIT_DIR/BISECT_TERMS"
}

check_term_format () {
        term=$1
        git check-ref-format refs/bisect/"$term" ||
        die "$(eval_gettext "'\$term' is not a valid term")"
        case "$term" in
        help|start|terms|skip|next|reset|visualize|replay|log|run)
                die "$(eval_gettext "can't use the builtin command '\$term' as a term")"
                ;;
        bad|new)
                if test "$2" != bad
                then
                        # In theory, nothing prevents swapping
                        # completely good and bad, but this situation
                        # could be confusing and hasn't been tested
                        # enough. Forbid it for now.
                        die "$(eval_gettext "can't change the meaning of term '\$term'")"
                fi
                ;;
        good|old)
                if test "$2" != good
                then
                        die "$(eval_gettext "can't change the meaning of term '\$term'")"
                fi
                ;;
        esac
}

check_and_set_terms () {
        cmd="$1"
        case "$cmd" in
        skip|start|terms) ;;
        *)
                if test -s "$GIT_DIR/BISECT_TERMS" && test "$cmd" != "$TERM_BAD" && test "$cmd" != "$TERM_GOOD"
                then
                        die "$(eval_gettext "Invalid command: you're currently in a \$TERM_BAD/\$TERM_GOOD bisect.")"
                fi
                case "$cmd" in
                bad|good)
                        if ! test -s "$GIT_DIR/BISECT_TERMS"
                        then
                                write_terms bad good
                        fi
                        ;;
                new|old)
                        if ! test -s "$GIT_DIR/BISECT_TERMS"
                        then
                                write_terms new old
                        fi
                        ;;
                esac ;;
        esac
}

bisect_voc () {
        case "$1" in
        bad) echo "bad|new" ;;
        good) echo "good|old" ;;
        esac
}

bisect_terms () {
        get_terms
        if ! test -s "$GIT_DIR/BISECT_TERMS"
        then
                die "$(gettext "no terms defined")"
        fi
        case "$#" in
        0)
                gettextln "Your current terms are $TERM_GOOD for the old state
and $TERM_BAD for the new state."
                ;;
        1)
                arg=$1
                case "$arg" in
                        --term-good|--term-old)
                                printf '%s\n' "$TERM_GOOD"
                                ;;
                        --term-bad|--term-new)
                                printf '%s\n' "$TERM_BAD"
                                ;;
                        *)
                                die "$(eval_gettext "invalid argument \$arg for 'git bisect terms'.
Supported options are: --term-good|--term-old and --term-bad|--term-new.")"
                                ;;
                esac
                ;;
        *)
                usage ;;
        esac
}

case "$#" in
0)
        usage ;;
*)
        cmd="$1"
        get_terms
        shift
        case "$cmd" in
        help)
                git bisect -h ;;
        start)
                bisect_start "$@" ;;
        bad|good|new|old|"$TERM_BAD"|"$TERM_GOOD")
                bisect_state "$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 "$@" ;;
        terms)
                bisect_terms "$@" ;;
        *)
                usage ;;
        esac
esac