rebase -i: teach --onto A...B syntax

diff --git a/git-rebase--interactive.sh b/git-rebase--interactive.sh
index 3dc659dd5896ce6c887eb786718919aef82f4ac6..f7ae02ccb57a4dbe4e7efc38f9c4615237704904 100755 (executable)
--- a/git-rebase--interactive.sh
+++ b/git-rebase--interactive.sh
@@ -420,7 +420,7 @@ do_next () {
        NEWHEAD=$(git rev-parse HEAD) &&
        case $HEADNAME in
        refs/*)
-               message="$GIT_REFLOG_ACTION: $HEADNAME onto $SHORTONTO)" &&
+               message="$GIT_REFLOG_ACTION: $HEADNAME onto $SHORTONTO" &&
                git update-ref -m "$message" $HEADNAME $NEWHEAD $OLDHEAD &&
                git symbolic-ref HEAD $HEADNAME
                ;;
@@ -442,6 +442,30 @@ do_rest () {
        done
 }
 
+# skip picking commits whose parents are unchanged
+skip_unnecessary_picks () {
+       fd=3
+       while read command sha1 rest
+       do
+               # fd=3 means we skip the command
+               case "$fd,$command,$(git rev-parse --verify --quiet $sha1^)" in
+               3,pick,"$ONTO"*|3,p,"$ONTO"*)
+                       # pick a commit whose parent is current $ONTO -> skip
+                       ONTO=$sha1
+                       ;;
+               3,#*|3,,*)
+                       # copy comments
+                       ;;
+               *)
+                       fd=1
+                       ;;
+               esac
+               echo "$command${sha1:+ }$sha1${rest:+ }$rest" >&$fd
+       done <"$TODO" >"$TODO.new" 3>>"$DONE" &&
+       mv -f "$TODO".new "$TODO" ||
+       die "Could not skip unnecessary pick commands"
+}
+
 # check if no other options are set
 is_standalone () {
        test $# -eq 2 -a "$2" = '--' &&
@@ -458,6 +482,25 @@ get_saved_options () {
        test -f "$DOTEST"/rebase-root && REBASE_ROOT=t
 }
 
+LF='
+'
+parse_onto () {
+       case "$1" in
+       *...*)
+               if      left=${1%...*} right=${1#*...} &&
+                       onto=$(git merge-base --all ${left:-HEAD} ${right:-HEAD})
+               then
+                       case "$onto" in
+                       ?*"$LF"?* | '')
+                               exit 1 ;;
+                       esac
+                       echo "$onto"
+                       exit 0
+               fi
+       esac
+       git rev-parse --verify "$1^0"
+}
+
 while test $# != 0
 do
        case "$1" in
@@ -565,7 +608,7 @@ first and then run 'git rebase --continue' again."
                ;;
        --onto)
                shift
-               ONTO=$(git rev-parse --verify "$1") ||
+               ONTO=$(parse_onto "$1") ||
                        die "Does not point to a valid commit: $1"
                ;;
        --)
@@ -679,7 +722,7 @@ first and then run 'git rebase --continue' again."
                                        preserve=t
                                        for p in $(git rev-list --parents -1 $sha1 | cut -d' ' -s -f2-)
                                        do
-                                               if test -f "$REWRITTEN"/$p -a \( $p != $UPSTREAM -o $sha1 = $first_after_upstream \)
+                                               if test -f "$REWRITTEN"/$p -a \( $p != $ONTO -o $sha1 = $first_after_upstream \)
                                                then
                                                        preserve=f
                                                fi
@@ -746,6 +789,8 @@ EOF
                has_action "$TODO" ||
                        die_abort "Nothing to do"
 
+               test -d "$REWRITTEN" || skip_unnecessary_picks
+
                git update-ref ORIG_HEAD $HEAD
                output git checkout $ONTO && do_rest
                ;;