# Copyright (c) 2005 Junio C Hamano.
#
-USAGE='<upstream> [<head>]'
+USAGE='[--onto <newbase>] <upstream> [<branch>]'
+LONG_USAGE='git-rebase applies to <upstream> (or optionally to <newbase>) commits
+from <branch> that do not appear in <upstream>. When <branch> is not
+specified it defaults to the current branch (HEAD).
+
+When git-rebase is complete, <branch> will be updated to point to the
+newly created line of commit objects, so the previous line will not be
+accessible unless there are other references to it already.
+
+Assuming the following history:
+
+ A---B---C topic
+ /
+ D---E---F---G master
+
+The result of the following command:
+
+ git-rebase --onto master~1 master topic
+
+ would be:
+
+ A'\''--B'\''--C'\'' topic
+ /
+ D---E---F---G master
+'
+
. git-sh-setup
+unset newbase
+while case "$#" in 0) break ;; esac
+do
+ case "$1" in
+ --onto)
+ test 2 -le "$#" || usage
+ newbase="$2"
+ shift
+ ;;
+ -*)
+ usage
+ ;;
+ *)
+ break
+ ;;
+ esac
+ shift
+done
+
# Make sure we do not have .dotest
if mkdir .dotest
then
exit 1
fi
-# The other head is given. Make sure it is valid.
-other=$(git-rev-parse --verify "$1^0") || usage
-
-# Make sure we have HEAD that is valid.
-head=$(git-rev-parse --verify "HEAD^0") || exit
-
# The tree must be really really clean.
git-update-index --refresh || exit
diff=$(git-diff-index --cached --name-status -r HEAD)
-case "$different" in
+case "$diff" in
?*) echo "$diff"
exit 1
;;
esac
+# The upstream head must be given. Make sure it is valid.
+upstream_name="$1"
+upstream=`git rev-parse --verify "${upstream_name}^0"` ||
+ die "invalid upstream $upstream_name"
+
+# If a hook exists, give it a chance to interrupt
+if test -x "$GIT_DIR/hooks/pre-rebase"
+then
+ "$GIT_DIR/hooks/pre-rebase" ${1+"$@"} || {
+ echo >&2 "The pre-rebase hook refused to rebase."
+ exit 1
+ }
+fi
+
# If the branch to rebase is given, first switch to it.
case "$#" in
2)
+ branch_name="$2"
git-checkout "$2" || usage
+ ;;
+*)
+ branch_name=`git symbolic-ref HEAD` || die "No current branch"
+ branch_name=`expr "z$branch_name" : 'zrefs/heads/\(.*\)'`
+ ;;
esac
+branch=$(git-rev-parse --verify "${branch_name}^0") || exit
+
+# Make sure the branch to rebase onto is valid.
+onto_name=${newbase-"$upstream_name"}
+onto=$(git-rev-parse --verify "${onto_name}^0") || exit
+
+# Now we are rebasing commits $upstream..$branch on top of $onto
+
+# Check if we are already based on $onto, but this should be
+# done only when upstream and onto are the same.
+if test "$upstream" = "onto"
+then
+ mb=$(git-merge-base "$onto" "$branch")
+ if test "$mb" = "$onto"
+ then
+ echo >&2 "Current branch $branch_name is up to date."
+ exit 0
+ fi
+fi
+
+# Rewind the head to "$onto"; this saves our current head in ORIG_HEAD.
+git-reset --hard "$onto"
-# If the HEAD is a proper descendant of $other, we do not even need
-# to rebase. Make sure we do not do needless rebase. In such a
-# case, merge-base should be the same as "$other".
-mb=$(git-merge-base "$other" "$head")
-if test "$mb" = "$other"
+# If the $onto is a proper descendant of the tip of the branch, then
+# we just fast forwarded.
+if test "$mb" = "$onto"
then
- echo >&2 "Current branch `git-symbolic-ref HEAD` is up to date."
+ echo >&2 "Fast-forwarded $branch to $newbase."
exit 0
fi
-# Rewind the head to "$other"
-git-reset --hard "$other"
-git-format-patch -k --stdout --full-index "$other" ORIG_HEAD |
+git-format-patch -k --stdout --full-index "$upstream" ORIG_HEAD |
git am --binary -3 -k