# Copyright (c) 2005 Junio C Hamano.
#
-. git-sh-setup || die "Not a git archive."
+USAGE='[--onto <newbase>] <upstream> [<branch>]'
+LONG_USAGE='If <branch> is specified, switch to that branch first. Then,
+extract commits in the current branch that are not in <upstream>,
+and reconstruct the current on top of <upstream>, discarding the original
+development history. If --onto <newbase> is specified, the history is
+reconstructed on top of <newbase>, instead of <upstream>. For example,
+while on "topic" branch:
-usage="usage: $0 "'<upstream> [<head>]
+ A---B---C topic
+ /
+ D---E---F---G master
-Uses output from git-cherry to rebase local commits to the new head of
-upstream tree.'
+ $ '"$0"' --onto master~1 master topic
-case "$#,$1" in
-1,*..*)
- upstream=$(expr "$1" : '\(.*\)\.\.') ours=$(expr "$1" : '.*\.\.\(.*\)$')
- set x "$upstream" "$ours"
- shift ;;
-esac
+would rewrite the history to look like this:
+
+
+ A'\''--B'\''--C'\'' topic
+ /
+ D---E---F---G master
+'
+
+. git-sh-setup
+
+unset newbase
+while case "$#" in 0) break ;; esac
+do
+ case "$1" in
+ --onto)
+ test 2 -le "$#" || usage
+ newbase="$2"
+ shift
+ ;;
+ -*)
+ usage
+ ;;
+ *)
+ break
+ ;;
+ esac
+ shift
+done
+# Make sure we do not have .dotest
+if mkdir .dotest
+then
+ rmdir .dotest
+else
+ echo >&2 '
+It seems that I cannot create a .dotest directory, and I wonder if you
+are in the middle of patch application or another rebase. If that is not
+the case, please rm -fr .dotest and run me again. I am stopping in case
+you still have something valuable there.'
+ exit 1
+fi
+
+# The tree must be really really clean.
git-update-index --refresh || exit
+diff=$(git-diff-index --cached --name-status -r HEAD)
+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 upsteram $upstream_name"
+
+# If a hook exists, give it a chance to interrupt
+if test -x "$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
-1) ours_symbolic=HEAD ;;
-2) ours_symbolic="$2" ;;
-*) die "$usage" ;;
+2)
+ branch_name="$2"
+ git-checkout "$2" || usage
+ ;;
+*)
+ branch_name=`git symbolic-ref HEAD` || die "No current branch"
+ branch_name=`expr "$branch_name" : 'refs/heads/\(.*\)'`
+ ;;
esac
+branch=$(git-rev-parse --verify "${branch_name}^0") || exit
-upstream=`git-rev-parse --verify "$1"` &&
-ours=`git-rev-parse --verify "$ours_symbolic"` || exit
-different1=$(git-diff-index --name-only --cached "$ours") &&
-different2=$(git-diff-index --name-only "$ours") &&
-test "$different1$different2" = "" ||
-die "Your working tree does not match $ours_symbolic."
+# Make sure the branch to rebase onto is valid.
+onto_name=${newbase-"$upstream_name"}
+onto=$(git-rev-parse --verify "${onto_name}^0") || exit
-git-read-tree -m -u $ours $upstream &&
-new_head=$(git-rev-parse --verify "$upstream^0") &&
-git-update-ref HEAD "$new_head" || exit
+# Now we are rebasing commits $upstream..$branch on top of $onto
-tmp=.rebase-tmp$$
-fail=$tmp-fail
-trap "rm -rf $tmp-*" 1 2 3 15
+# 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 $branch_name is up to date."
+ exit 0
+ fi
+fi
->$fail
+# Rewind the head to "$onto"; this saves our current head in ORIG_HEAD.
+git-reset --hard "$onto"
-git-cherry -v $upstream $ours |
-while read sign commit msg
-do
- case "$sign" in
- -)
- echo >&2 "* Already applied: $msg"
- continue ;;
- esac
- echo >&2 "* Applying: $msg"
- S=$(git-rev-parse --verify HEAD) &&
- git-cherry-pick --replay $commit || {
- echo >&2 "* Not applying the patch and continuing."
- echo $commit >>$fail
- git-reset --hard $S
- }
-done
-if test -s $fail
+# 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 Some commits could not be rebased, check by hand:
- cat >&2 $fail
- echo >&2 "(the same list of commits are found in $tmp)"
- exit 1
-else
- rm -f $fail
+ echo >&2 "Fast-forwarded $branch to $newbase."
+ exit 0
fi
+
+git-format-patch -k --stdout --full-index "$upstream" ORIG_HEAD |
+git am --binary -3 -k