Merge branch 'mz/rebase'

* mz/rebase: (34 commits)
  rebase: define options in OPTIONS_SPEC
  Makefile: do not install sourced rebase scripts
  rebase: use @{upstream} if no upstream specified
  rebase -i: remove unnecessary state rebase-root
  rebase -i: don't read unused variable preserve_merges
  git-rebase--am: remove unnecessary --3way option
  rebase -m: don't print exit code 2 when merge fails
  rebase -m: remember allow_rerere_autoupdate option
  rebase: remember strategy and strategy options
  rebase: remember verbose option
  rebase: extract code for writing basic state
  rebase: factor out sub command handling
  rebase: make -v a tiny bit more verbose
  rebase -i: align variable names
  rebase: show consistent conflict resolution hint
  rebase: extract am code to new source file
  rebase: extract merge code to new source file
  rebase: remove $branch as synonym for $orig_head
  rebase -i: support --stat
  rebase: factor out call to pre-rebase hook
  ...

14 files changed, 844 insertions, 868 deletions

diff --git a/.gitignore b/.gitignore
index 2cf3ca5808..711fce7e08 100644
--- a/.gitignore
+++ b/.gitignore
@@ -101,7 +101,9 @@
 /git-quiltimport
 /git-read-tree
 /git-rebase
+/git-rebase--am
 /git-rebase--interactive
+/git-rebase--merge
 /git-receive-pack
 /git-reflog
 /git-relink
diff --git a/Documentation/config.txt b/Documentation/config.txt
index ce17805509..480dd0a861 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -641,7 +641,7 @@ branch.<name>.remote::
 
 branch.<name>.merge::
 	Defines, together with branch.<name>.remote, the upstream branch
-	for the given branch. It tells 'git fetch'/'git pull' which
+	for the given branch. It tells 'git fetch'/'git pull'/'git rebase' which
 	branch to merge and can also affect 'git push' (see push.default).
 	When in branch <name>, it tells 'git fetch' the default
 	refspec to be marked for merging in FETCH_HEAD. The value is
diff --git a/Documentation/git-rebase.txt b/Documentation/git-rebase.txt
index 620d50e71f..9a075bc4d2 100644
--- a/Documentation/git-rebase.txt
+++ b/Documentation/git-rebase.txt
@@ -9,7 +9,7 @@ SYNOPSIS
 --------
 [verse]
 'git rebase' [-i | --interactive] [options] [--onto <newbase>]
-	<upstream> [<branch>]
+	[<upstream>] [<branch>]
 'git rebase' [-i | --interactive] [options] --onto <newbase>
 	--root [<branch>]
 
@@ -21,6 +21,12 @@ If <branch> is specified, 'git rebase' will perform an automatic
 `git checkout <branch>` before doing anything else.  Otherwise
 it remains on the current branch.
 
+If <upstream> is not specified, the upstream configured in
+branch.<name>.remote and branch.<name>.merge options will be used; see
+linkgit:git-config[1] for details.  If you are currently not on any
+branch or if the current branch does not have a configured upstream,
+the rebase will abort.
+
 All changes made by commits in the current branch but that are not
 in <upstream> are saved to a temporary area.  This is the same set
 of commits that would be shown by `git log <upstream>..HEAD` (or
@@ -217,7 +223,8 @@ leave out at most one of A and B, in which case it defaults to HEAD.
 
 <upstream>::
 	Upstream branch to compare against.  May be any valid commit,
-	not just an existing branch name.
+	not just an existing branch name. Defaults to the configured
+	upstream for the current branch.
 
 <branch>::
 	Working branch; defaults to HEAD.
diff --git a/Makefile b/Makefile
index c7c1530b89..3a1fe20ff2 100644
--- a/Makefile
+++ b/Makefile
@@ -368,7 +368,6 @@ SCRIPT_SH += git-merge-resolve.sh
 SCRIPT_SH += git-mergetool.sh
 SCRIPT_SH += git-pull.sh
 SCRIPT_SH += git-quiltimport.sh
-SCRIPT_SH += git-rebase--interactive.sh
 SCRIPT_SH += git-rebase.sh
 SCRIPT_SH += git-repack.sh
 SCRIPT_SH += git-request-pull.sh
@@ -378,6 +377,9 @@ SCRIPT_SH += git-web--browse.sh
 
 SCRIPT_LIB += git-mergetool--lib
 SCRIPT_LIB += git-parse-remote
+SCRIPT_LIB += git-rebase--am
+SCRIPT_LIB += git-rebase--interactive
+SCRIPT_LIB += git-rebase--merge
 SCRIPT_LIB += git-sh-setup
 
 SCRIPT_PERL += git-add--interactive.perl
diff --git a/git-parse-remote.sh b/git-parse-remote.sh
index ea093d251d..b24119d69c 100644
--- a/git-parse-remote.sh
+++ b/git-parse-remote.sh
@@ -50,3 +50,41 @@ get_remote_merge_branch () {
 	    esac
 	esac
 }
+
+error_on_missing_default_upstream () {
+	cmd="$1"
+	op_type="$2"
+	op_prep="$3"
+	example="$4"
+	branch_name=$(git symbolic-ref -q HEAD)
+	if test -z "$branch_name"
+	then
+		echo "You are not currently on a branch, so I cannot use any
+'branch.<branchname>.merge' in your configuration file.
+Please specify which branch you want to $op_type $op_prep on the command
+line and try again (e.g. '$example').
+See git-${cmd}(1) for details."
+	else
+		echo "You asked me to $cmd without telling me which branch you
+want to $op_type $op_prep, and 'branch.${branch_name#refs/heads/}.merge' in
+your configuration file does not tell me, either. Please
+specify which branch you want to use on the command line and
+try again (e.g. '$example').
+See git-${cmd}(1) for details.
+
+If you often $op_type $op_prep the same branch, you may want to
+use something like the following in your configuration file:
+    [branch \"${branch_name#refs/heads/}\"]
+    remote = <nickname>
+    merge = <remote-ref>"
+		test rebase = "$op_type" &&
+		echo "    rebase = true"
+		echo "
+    [remote \"<nickname>\"]
+    url = <url>
+    fetch = <refspec>
+
+See git-config(1) for details."
+	fi
+	exit 1
+}
diff --git a/git-pull.sh b/git-pull.sh
index 4e9e0e49ec..fb9e2df931 100755
--- a/git-pull.sh
+++ b/git-pull.sh
@@ -168,34 +168,10 @@ error_on_no_merge_candidates () {
 		echo "You asked to pull from the remote '$1', but did not specify"
 		echo "a branch. Because this is not the default configured remote"
 		echo "for your current branch, you must specify a branch on the command line."
-	elif [ -z "$curr_branch" ]; then
-		echo "You are not currently on a branch, so I cannot use any"
-		echo "'branch.<branchname>.merge' in your configuration file."
-		echo "Please specify which remote branch you want to use on the command"
-		echo "line and try again (e.g. 'git pull <repository> <refspec>')."
-		echo "See git-pull(1) for details."
-	elif [ -z "$upstream" ]; then
-		echo "You asked me to pull without telling me which branch you"
-		echo "want to $op_type $op_prep, and 'branch.${curr_branch}.merge' in"
-		echo "your configuration file does not tell me, either. Please"
-		echo "specify which branch you want to use on the command line and"
-		echo "try again (e.g. 'git pull <repository> <refspec>')."
-		echo "See git-pull(1) for details."
-		echo
-		echo "If you often $op_type $op_prep the same branch, you may want to"
-		echo "use something like the following in your configuration file:"
-		echo
-		echo "    [branch \"${curr_branch}\"]"
-		echo "    remote = <nickname>"
-		echo "    merge = <remote-ref>"
-		test rebase = "$op_type" &&
-			echo "    rebase = true"
-		echo
-		echo "    [remote \"<nickname>\"]"
-		echo "    url = <url>"
-		echo "    fetch = <refspec>"
-		echo
-		echo "See git-config(1) for details."
+	elif [ -z "$curr_branch" -o -z "$upstream" ]; then
+		. git-parse-remote
+		error_on_missing_default_upstream "pull" $op_type $op_prep \
+			"git pull <repository> <refspec>"
 	else
 		echo "Your configuration specifies to $op_type $op_prep the ref '${upstream#refs/heads/}'"
 		echo "from the remote, but no such ref was fetched."
diff --git a/git-rebase--am.sh b/git-rebase--am.sh
new file mode 100644
index 0000000000..c815a2412c
--- /dev/null
+++ b/git-rebase--am.sh
@@ -0,0 +1,30 @@
+#!/bin/sh
+#
+# Copyright (c) 2010 Junio C Hamano.
+#
+
+. git-sh-setup
+
+case "$action" in
+continue)
+	git am --resolved --resolvemsg="$resolvemsg" &&
+	move_to_original_branch
+	exit
+	;;
+skip)
+	git am --skip --resolvemsg="$resolvemsg" &&
+	move_to_original_branch
+	exit
+	;;
+esac
+
+test -n "$rebase_root" && root_flag=--root
+
+git format-patch -k --stdout --full-index --ignore-if-in-upstream \
+	--src-prefix=a/ --dst-prefix=b/ \
+	--no-renames $root_flag "$revisions" |
+git am $git_am_opt --rebasing --resolvemsg="$resolvemsg" &&
+move_to_original_branch
+ret=$?
+test 0 != $ret -a -d "$state_dir" && write_basic_state
+exit $ret
diff --git a/git-rebase--interactive.sh b/git-rebase--interactive.sh
index 5873ba4bc3..6566d319aa 100755..100644
--- a/git-rebase--interactive.sh
+++ b/git-rebase--interactive.sh
@@ -10,48 +10,22 @@
 # The original idea comes from Eric W. Biederman, in
 # http://article.gmane.org/gmane.comp.version-control.git/22407
 
-OPTIONS_KEEPDASHDASH=
-OPTIONS_SPEC="\
-git-rebase [-i] [options] [--] <upstream> [<branch>]
-git-rebase [-i] (--continue | --abort | --skip)
---
- Available options are
-v,verbose          display a diffstat of what changed upstream
-onto=              rebase onto given branch instead of upstream
-p,preserve-merges  try to recreate merges instead of ignoring them
-s,strategy=        use the given merge strategy
-no-ff              cherry-pick all commits, even if unchanged
-m,merge            always used (no-op)
-i,interactive      always used (no-op)
- Actions:
-continue           continue rebasing process
-abort              abort rebasing process and restore original branch
-skip               skip current patch and continue rebasing process
-no-verify          override pre-rebase hook from stopping the operation
-verify             allow pre-rebase hook to run
-root               rebase all reachable commmits up to the root(s)
-autosquash         move commits that begin with squash!/fixup! under -i
-"
-
 . git-sh-setup
-require_work_tree
-
-DOTEST="$GIT_DIR/rebase-merge"
 
 # The file containing rebase commands, comments, and empty lines.
 # This file is created by "git rebase -i" then edited by the user.  As
 # the lines are processed, they are removed from the front of this
-# file and written to the tail of $DONE.
-TODO="$DOTEST"/git-rebase-todo
+# file and written to the tail of $done.
+todo="$state_dir"/git-rebase-todo
 
 # The rebase command lines that have already been processed.  A line
 # is moved here when it is first handled, before any associated user
 # actions.
-DONE="$DOTEST"/done
+done="$state_dir"/done
 
 # The commit message that is planned to be used for any changes that
 # need to be committed following a user interaction.
-MSG="$DOTEST"/message
+msg="$state_dir"/message
 
 # The file into which is accumulated the suggested commit message for
 # squash/fixup commands.  When the first of a series of squash/fixups
@@ -61,34 +35,34 @@ MSG="$DOTEST"/message
 # is appended to the file as it is processed.
 #
 # The first line of the file is of the form
-#     # This is a combination of $COUNT commits.
-# where $COUNT is the number of commits whose messages have been
+#     # This is a combination of $count commits.
+# where $count is the number of commits whose messages have been
 # written to the file so far (including the initial "pick" commit).
 # Each time that a commit message is processed, this line is read and
 # updated.  It is deleted just before the combined commit is made.
-SQUASH_MSG="$DOTEST"/message-squash
+squash_msg="$state_dir"/message-squash
 
 # If the current series of squash/fixups has not yet included a squash
 # command, then this file exists and holds the commit message of the
 # original "pick" commit.  (If the series ends without a "squash"
 # command, then this can be used as the commit message of the combined
 # commit without opening the editor.)
-FIXUP_MSG="$DOTEST"/message-fixup
+fixup_msg="$state_dir"/message-fixup
 
-# $REWRITTEN is the name of a directory containing files for each
-# commit that is reachable by at least one merge base of $HEAD and
-# $UPSTREAM. They are not necessarily rewritten, but their children
+# $rewritten is the name of a directory containing files for each
+# commit that is reachable by at least one merge base of $head and
+# $upstream. They are not necessarily rewritten, but their children
 # might be.  This ensures that commits on merged, but otherwise
 # unrelated side branches are left alone. (Think "X" in the man page's
 # example.)
-REWRITTEN="$DOTEST"/rewritten
+rewritten="$state_dir"/rewritten
 
-DROPPED="$DOTEST"/dropped
+dropped="$state_dir"/dropped
 
 # A script to set the GIT_AUTHOR_NAME, GIT_AUTHOR_EMAIL, and
 # GIT_AUTHOR_DATE that will be used for the commit that is currently
 # being rebased.
-AUTHOR_SCRIPT="$DOTEST"/author-script
+author_script="$state_dir"/author-script
 
 # When an "edit" rebase command is being processed, the SHA1 of the
 # commit to be edited is recorded in this file.  When "git rebase
@@ -96,69 +70,31 @@ AUTHOR_SCRIPT="$DOTEST"/author-script
 # will be amended to the HEAD commit, but only provided the HEAD
 # commit is still the commit to be edited.  When any other rebase
 # command is processed, this file is deleted.
-AMEND="$DOTEST"/amend
+amend="$state_dir"/amend
 
 # For the post-rewrite hook, we make a list of rewritten commits and
 # their new sha1s.  The rewritten-pending list keeps the sha1s of
 # commits that have been processed, but not committed yet,
 # e.g. because they are waiting for a 'squash' command.
-REWRITTEN_LIST="$DOTEST"/rewritten-list
-REWRITTEN_PENDING="$DOTEST"/rewritten-pending
-
-PRESERVE_MERGES=
-STRATEGY=
-ONTO=
-VERBOSE=
-OK_TO_SKIP_PRE_REBASE=
-REBASE_ROOT=
-AUTOSQUASH=
-test "$(git config --bool rebase.autosquash)" = "true" && AUTOSQUASH=t
-NEVER_FF=
-
-GIT_CHERRY_PICK_HELP="\
-hint: after resolving the conflicts, mark the corrected paths
-hint: with 'git add <paths>' and run 'git rebase --continue'"
+rewritten_list="$state_dir"/rewritten-list
+rewritten_pending="$state_dir"/rewritten-pending
+
+GIT_CHERRY_PICK_HELP="$resolvemsg"
 export GIT_CHERRY_PICK_HELP
 
 warn () {
 	printf '%s\n' "$*" >&2
 }
 
-output () {
-	case "$VERBOSE" in
-	'')
-		output=$("$@" 2>&1 )
-		status=$?
-		test $status != 0 && printf "%s\n" "$output"
-		return $status
-		;;
-	*)
-		"$@"
-		;;
-	esac
-}
-
 # Output the commit message for the specified commit.
 commit_message () {
 	git cat-file commit "$1" | sed "1,/^$/d"
 }
 
-run_pre_rebase_hook () {
-	if test -z "$OK_TO_SKIP_PRE_REBASE" &&
-	   test -x "$GIT_DIR/hooks/pre-rebase"
-	then
-		"$GIT_DIR/hooks/pre-rebase" ${1+"$@"} || {
-			echo >&2 "The pre-rebase hook refused to rebase."
-			exit 1
-		}
-	fi
-}
-
-
-ORIG_REFLOG_ACTION="$GIT_REFLOG_ACTION"
+orig_reflog_action="$GIT_REFLOG_ACTION"
 
 comment_for_reflog () {
-	case "$ORIG_REFLOG_ACTION" in
+	case "$orig_reflog_action" in
 	''|rebase*)
 		GIT_REFLOG_ACTION="rebase -i ($1)"
 		export GIT_REFLOG_ACTION
@@ -168,16 +104,16 @@ comment_for_reflog () {
 
 last_count=
 mark_action_done () {
-	sed -e 1q < "$TODO" >> "$DONE"
-	sed -e 1d < "$TODO" >> "$TODO".new
-	mv -f "$TODO".new "$TODO"
-	count=$(sane_grep -c '^[^#]' < "$DONE")
-	total=$(($count+$(sane_grep -c '^[^#]' < "$TODO")))
-	if test "$last_count" != "$count"
+	sed -e 1q < "$todo" >> "$done"
+	sed -e 1d < "$todo" >> "$todo".new
+	mv -f "$todo".new "$todo"
+	new_count=$(sane_grep -c '^[^#]' < "$done")
+	total=$(($new_count+$(sane_grep -c '^[^#]' < "$todo")))
+	if test "$last_count" != "$new_count"
 	then
-		last_count=$count
-		printf "Rebasing (%d/%d)\r" $count $total
-		test -z "$VERBOSE" || echo
+		last_count=$new_count
+		printf "Rebasing (%d/%d)\r" $new_count $total
+		test -z "$verbose" || echo
 	fi
 }
 
@@ -193,22 +129,22 @@ make_patch () {
 	*)
 		echo "Root commit"
 		;;
-	esac > "$DOTEST"/patch
-	test -f "$MSG" ||
-		commit_message "$1" > "$MSG"
-	test -f "$AUTHOR_SCRIPT" ||
-		get_author_ident_from_commit "$1" > "$AUTHOR_SCRIPT"
+	esac > "$state_dir"/patch
+	test -f "$msg" ||
+		commit_message "$1" > "$msg"
+	test -f "$author_script" ||
+		get_author_ident_from_commit "$1" > "$author_script"
 }
 
 die_with_patch () {
-	echo "$1" > "$DOTEST"/stopped-sha
+	echo "$1" > "$state_dir"/stopped-sha
 	make_patch "$1"
 	git rerere
 	die "$2"
 }
 
 die_abort () {
-	rm -rf "$DOTEST"
+	rm -rf "$state_dir"
 	die "$1"
 }
 
@@ -228,15 +164,10 @@ do_with_author () {
 pick_one () {
 	ff=--ff
 	case "$1" in -n) sha1=$2; ff= ;; *) sha1=$1 ;; esac
-	case "$NEVER_FF" in '') ;; ?*) ff= ;; esac
+	case "$force_rebase" in '') ;; ?*) ff= ;; esac
 	output git rev-parse --verify $sha1 || die "Invalid commit name: $sha1"
-	test -d "$REWRITTEN" &&
+	test -d "$rewritten" &&
 		pick_one_preserving_merges "$@" && return
-	if test -n "$REBASE_ROOT"
-	then
-		output git cherry-pick "$@"
-		return
-	fi
 	output git cherry-pick $ff "$@"
 }
 
@@ -253,20 +184,20 @@ pick_one_preserving_merges () {
 	esac
 	sha1=$(git rev-parse $sha1)
 
-	if test -f "$DOTEST"/current-commit
+	if test -f "$state_dir"/current-commit
 	then
 		if test "$fast_forward" = t
 		then
 			while read current_commit
 			do
-				git rev-parse HEAD > "$REWRITTEN"/$current_commit
-			done <"$DOTEST"/current-commit
-			rm "$DOTEST"/current-commit ||
+				git rev-parse HEAD > "$rewritten"/$current_commit
+			done <"$state_dir"/current-commit
+			rm "$state_dir"/current-commit ||
 			die "Cannot write current commit's replacement sha1"
 		fi
 	fi
 
-	echo $sha1 >> "$DOTEST"/current-commit
+	echo $sha1 >> "$state_dir"/current-commit
 
 	# rewrite parents; if none were rewritten, we can fast-forward.
 	new_parents=
@@ -280,9 +211,9 @@ pick_one_preserving_merges () {
 		p=$(expr "$pend" : ' \([^ ]*\)')
 		pend="${pend# $p}"
 
-		if test -f "$REWRITTEN"/$p
+		if test -f "$rewritten"/$p
 		then
-			new_p=$(cat "$REWRITTEN"/$p)
+			new_p=$(cat "$rewritten"/$p)
 
 			# If the todo reordered commits, and our parent is marked for
 			# rewriting, but hasn't been gotten to yet, assume the user meant to
@@ -301,10 +232,10 @@ pick_one_preserving_merges () {
 				;;
 			esac
 		else
-			if test -f "$DROPPED"/$p
+			if test -f "$dropped"/$p
 			then
 				fast_forward=f
-				replacement="$(cat "$DROPPED"/$p)"
+				replacement="$(cat "$dropped"/$p)"
 				test -z "$replacement" && replacement=root
 				pend=" $replacement$pend"
 			else
@@ -333,18 +264,19 @@ pick_one_preserving_merges () {
 			test "a$1" = a-n && die "Refusing to squash a merge: $sha1"
 
 			# redo merge
-			author_script=$(get_author_ident_from_commit $sha1)
-			eval "$author_script"
-			msg="$(commit_message $sha1)"
+			author_script_content=$(get_author_ident_from_commit $sha1)
+			eval "$author_script_content"
+			msg_content="$(commit_message $sha1)"
 			# No point in merging the first parent, that's HEAD
 			new_parents=${new_parents# $first_parent}
 			if ! do_with_author output \
-				git merge $STRATEGY -m "$msg" $new_parents
+				git merge ${strategy:+-s $strategy} -m \
+					"$msg_content" $new_parents
 			then
-				printf "%s\n" "$msg" > "$GIT_DIR"/MERGE_MSG
+				printf "%s\n" "$msg_content" > "$GIT_DIR"/MERGE_MSG
 				die_with_patch $sha1 "Error redoing merge $sha1"
 			fi
-			echo "$sha1 $(git rev-parse HEAD^0)" >> "$REWRITTEN_LIST"
+			echo "$sha1 $(git rev-parse HEAD^0)" >> "$rewritten_list"
 			;;
 		*)
 			output git cherry-pick "$@" ||
@@ -365,46 +297,46 @@ nth_string () {
 }
 
 update_squash_messages () {
-	if test -f "$SQUASH_MSG"; then
-		mv "$SQUASH_MSG" "$SQUASH_MSG".bak || exit
-		COUNT=$(($(sed -n \
+	if test -f "$squash_msg"; then
+		mv "$squash_msg" "$squash_msg".bak || exit
+		count=$(($(sed -n \
 			-e "1s/^# This is a combination of \(.*\) commits\./\1/p" \
-			-e "q" < "$SQUASH_MSG".bak)+1))
+			-e "q" < "$squash_msg".bak)+1))
 		{
-			echo "# This is a combination of $COUNT commits."
+			echo "# This is a combination of $count commits."
 			sed -e 1d -e '2,/^./{
 				/^$/d
-			}' <"$SQUASH_MSG".bak
-		} >"$SQUASH_MSG"
+			}' <"$squash_msg".bak
+		} >"$squash_msg"
 	else
-		commit_message HEAD > "$FIXUP_MSG" || die "Cannot write $FIXUP_MSG"
-		COUNT=2
+		commit_message HEAD > "$fixup_msg" || die "Cannot write $fixup_msg"
+		count=2
 		{
 			echo "# This is a combination of 2 commits."
 			echo "# The first commit's message is:"
 			echo
-			cat "$FIXUP_MSG"
-		} >"$SQUASH_MSG"
+			cat "$fixup_msg"
+		} >"$squash_msg"
 	fi
 	case $1 in
 	squash)
-		rm -f "$FIXUP_MSG"
+		rm -f "$fixup_msg"
 		echo
-		echo "# This is the $(nth_string $COUNT) commit message:"
+		echo "# This is the $(nth_string $count) commit message:"
 		echo
 		commit_message $2
 		;;
 	fixup)
 		echo
-		echo "# The $(nth_string $COUNT) commit message will be skipped:"
+		echo "# The $(nth_string $count) commit message will be skipped:"
 		echo
 		commit_message $2 | sed -e 's/^/#	/'
 		;;
-	esac >>"$SQUASH_MSG"
+	esac >>"$squash_msg"
 }
 
 peek_next_command () {
-	sed -n -e "/^#/d" -e '/^$/d' -e "s/ .*//p" -e "q" < "$TODO"
+	sed -n -e "/^#/d" -e '/^$/d' -e "s/ .*//p" -e "q" < "$todo"
 }
 
 # A squash/fixup has failed.  Prepare the long version of the squash
@@ -414,24 +346,24 @@ peek_next_command () {
 # messages, effectively causing the combined commit to be used as the
 # new basis for any further squash/fixups.  Args: sha1 rest
 die_failed_squash() {
-	mv "$SQUASH_MSG" "$MSG" || exit
-	rm -f "$FIXUP_MSG"
-	cp "$MSG" "$GIT_DIR"/MERGE_MSG || exit
+	mv "$squash_msg" "$msg" || exit
+	rm -f "$fixup_msg"
+	cp "$msg" "$GIT_DIR"/MERGE_MSG || exit
 	warn
 	warn "Could not apply $1... $2"
 	die_with_patch $1 ""
 }
 
 flush_rewritten_pending() {
-	test -s "$REWRITTEN_PENDING" || return
+	test -s "$rewritten_pending" || return
 	newsha1="$(git rev-parse HEAD^0)"
-	sed "s/$/ $newsha1/" < "$REWRITTEN_PENDING" >> "$REWRITTEN_LIST"
-	rm -f "$REWRITTEN_PENDING"
+	sed "s/$/ $newsha1/" < "$rewritten_pending" >> "$rewritten_list"
+	rm -f "$rewritten_pending"
 }
 
 record_in_rewritten() {
 	oldsha1="$(git rev-parse $1)"
-	echo "$oldsha1" >> "$REWRITTEN_PENDING"
+	echo "$oldsha1" >> "$rewritten_pending"
 
 	case "$(peek_next_command)" in
 	squash|s|fixup|f)
@@ -443,8 +375,8 @@ record_in_rewritten() {
 }
 
 do_next () {
-	rm -f "$MSG" "$AUTHOR_SCRIPT" "$AMEND" || exit
-	read -r command sha1 rest < "$TODO"
+	rm -f "$msg" "$author_script" "$amend" || exit
+	read -r command sha1 rest < "$todo"
 	case "$command" in
 	'#'*|''|noop)
 		mark_action_done
@@ -472,9 +404,9 @@ do_next () {
 		mark_action_done
 		pick_one $sha1 ||
 			die_with_patch $sha1 "Could not apply $sha1... $rest"
-		echo "$sha1" > "$DOTEST"/stopped-sha
+		echo "$sha1" > "$state_dir"/stopped-sha
 		make_patch $sha1
-		git rev-parse --verify HEAD > "$AMEND"
+		git rev-parse --verify HEAD > "$amend"
 		warn "Stopped at $sha1... $rest"
 		warn "You can amend the commit now, with"
 		warn
@@ -497,47 +429,47 @@ do_next () {
 		esac
 		comment_for_reflog $squash_style
 
-		test -f "$DONE" && has_action "$DONE" ||
+		test -f "$done" && has_action "$done" ||
 			die "Cannot '$squash_style' without a previous commit"
 
 		mark_action_done
 		update_squash_messages $squash_style $sha1
-		author_script=$(get_author_ident_from_commit HEAD)
-		echo "$author_script" > "$AUTHOR_SCRIPT"
-		eval "$author_script"
+		author_script_content=$(get_author_ident_from_commit HEAD)
+		echo "$author_script_content" > "$author_script"
+		eval "$author_script_content"
 		output git reset --soft HEAD^
 		pick_one -n $sha1 || die_failed_squash $sha1 "$rest"
 		case "$(peek_next_command)" in
 		squash|s|fixup|f)
 			# This is an intermediate commit; its message will only be
 			# used in case of trouble.  So use the long version:
-			do_with_author output git commit --no-verify -F "$SQUASH_MSG" ||
+			do_with_author output git commit --no-verify -F "$squash_msg" ||
 				die_failed_squash $sha1 "$rest"
 			;;
 		*)
 			# This is the final command of this squash/fixup group
-			if test -f "$FIXUP_MSG"
+			if test -f "$fixup_msg"
 			then
-				do_with_author git commit --no-verify -F "$FIXUP_MSG" ||
+				do_with_author git commit --no-verify -F "$fixup_msg" ||
 					die_failed_squash $sha1 "$rest"
 			else
-				cp "$SQUASH_MSG" "$GIT_DIR"/SQUASH_MSG || exit
+				cp "$squash_msg" "$GIT_DIR"/SQUASH_MSG || exit
 				rm -f "$GIT_DIR"/MERGE_MSG
 				do_with_author git commit --no-verify -e ||
 					die_failed_squash $sha1 "$rest"
 			fi
-			rm -f "$SQUASH_MSG" "$FIXUP_MSG"
+			rm -f "$squash_msg" "$fixup_msg"
 			;;
 		esac
 		record_in_rewritten $sha1
 		;;
 	x|"exec")
-		read -r command rest < "$TODO"
+		read -r command rest < "$todo"
 		mark_action_done
 		printf 'Executing: %s\n' "$rest"
 		# "exec" command doesn't take a sha1 in the todo-list.
 		# => can't just use $sha1 here.
-		git rev-parse --verify HEAD > "$DOTEST"/stopped-sha
+		git rev-parse --verify HEAD > "$state_dir"/stopped-sha
 		${SHELL:-@SHELL_PATH@} -c "$rest" # Actual execution
 		status=$?
 		if test "$status" -ne 0
@@ -563,42 +495,40 @@ do_next () {
 		warn "Unknown command: $command $sha1 $rest"
 		if git rev-parse --verify -q "$sha1" >/dev/null
 		then
-			die_with_patch $sha1 "Please fix this in the file $TODO."
+			die_with_patch $sha1 "Please fix this in the file $todo."
 		else
-			die "Please fix this in the file $TODO."
+			die "Please fix this in the file $todo."
 		fi
 		;;
 	esac
-	test -s "$TODO" && return
+	test -s "$todo" && return
 
 	comment_for_reflog finish &&
-	HEADNAME=$(cat "$DOTEST"/head-name) &&
-	OLDHEAD=$(cat "$DOTEST"/head) &&
-	SHORTONTO=$(git rev-parse --short $(cat "$DOTEST"/onto)) &&
-	NEWHEAD=$(git rev-parse HEAD) &&
-	case $HEADNAME in
+	shortonto=$(git rev-parse --short $onto) &&
+	newhead=$(git rev-parse HEAD) &&
+	case $head_name in
 	refs/*)
-		message="$GIT_REFLOG_ACTION: $HEADNAME onto $SHORTONTO" &&
-		git update-ref -m "$message" $HEADNAME $NEWHEAD $OLDHEAD &&
-		git symbolic-ref HEAD $HEADNAME
+		message="$GIT_REFLOG_ACTION: $head_name onto $shortonto" &&
+		git update-ref -m "$message" $head_name $newhead $orig_head &&
+		git symbolic-ref HEAD $head_name
 		;;
 	esac && {
-		test ! -f "$DOTEST"/verbose ||
-			git diff-tree --stat $(cat "$DOTEST"/head)..HEAD
+		test ! -f "$state_dir"/verbose ||
+			git diff-tree --stat $orig_head..HEAD
 	} &&
 	{
-		test -s "$REWRITTEN_LIST" &&
-		git notes copy --for-rewrite=rebase < "$REWRITTEN_LIST" ||
+		test -s "$rewritten_list" &&
+		git notes copy --for-rewrite=rebase < "$rewritten_list" ||
 		true # we don't care if this copying failed
 	} &&
 	if test -x "$GIT_DIR"/hooks/post-rewrite &&
-		test -s "$REWRITTEN_LIST"; then
-		"$GIT_DIR"/hooks/post-rewrite rebase < "$REWRITTEN_LIST"
+		test -s "$rewritten_list"; then
+		"$GIT_DIR"/hooks/post-rewrite rebase < "$rewritten_list"
 		true # we don't care if this hook failed
 	fi &&
-	rm -rf "$DOTEST" &&
+	rm -rf "$state_dir" &&
 	git gc --auto &&
-	warn "Successfully rebased and updated $HEADNAME."
+	warn "Successfully rebased and updated $head_name."
 
 	exit
 }
@@ -618,11 +548,11 @@ skip_unnecessary_picks () {
 		# fd=3 means we skip the command
 		case "$fd,$command" in
 		3,pick|3,p)
-			# pick a commit whose parent is current $ONTO -> skip
+			# pick a commit whose parent is current $onto -> skip
 			sha1=${rest%% *}
 			case "$(git rev-parse --verify --quiet "$sha1"^)" in
-			"$ONTO"*)
-				ONTO=$sha1
+			"$onto"*)
+				onto=$sha1
 				;;
 			*)
 				fd=1
@@ -637,32 +567,16 @@ skip_unnecessary_picks () {
 			;;
 		esac
 		printf '%s\n' "$command${rest:+ }$rest" >&$fd
-	done <"$TODO" >"$TODO.new" 3>>"$DONE" &&
-	mv -f "$TODO".new "$TODO" &&
+	done <"$todo" >"$todo.new" 3>>"$done" &&
+	mv -f "$todo".new "$todo" &&
 	case "$(peek_next_command)" in
 	squash|s|fixup|f)
-		record_in_rewritten "$ONTO"
+		record_in_rewritten "$onto"
 		;;
 	esac ||
 	die "Could not skip unnecessary pick commands"
 }
 
-# check if no other options are set
-is_standalone () {
-	test $# -eq 2 -a "$2" = '--' &&
-	test -z "$ONTO" &&
-	test -z "$PRESERVE_MERGES" &&
-	test -z "$STRATEGY" &&
-	test -z "$VERBOSE"
-}
-
-get_saved_options () {
-	test -d "$REWRITTEN" && PRESERVE_MERGES=t
-	test -f "$DOTEST"/strategy && STRATEGY="$(cat "$DOTEST"/strategy)"
-	test -f "$DOTEST"/verbose && VERBOSE=t
-	test -f "$DOTEST"/rebase-root && REBASE_ROOT=t
-}
-
 # Rearrange the todo list that has both "pick sha1 msg" and
 # "pick sha1 fixup!/squash! msg" appears in it so that the latter
 # comes immediately after the former, and change "pick" to
@@ -699,7 +613,7 @@ rearrange_squash () {
 		esac
 		printf '%s\n' "$pick $sha1 $message"
 		used="$used$sha1 "
-		while read -r squash action msg
+		while read -r squash action msg_content
 		do
 			case " $used" in
 			*" $squash "*) continue ;;
@@ -709,13 +623,13 @@ rearrange_squash () {
 			+*)
 				action="${action#+}"
 				# full sha1 prefix test
-				case "$msg" in "$sha1"*) emit=1;; esac ;;
+				case "$msg_content" in "$sha1"*) emit=1;; esac ;;
 			*)
 				# message prefix test
-				case "$message" in "$msg"*) emit=1;; esac ;;
+				case "$message" in "$msg_content"*) emit=1;; esac ;;
 			esac
 			if test $emit = 1; then
-				printf '%s\n' "$action $squash $action! $msg"
+				printf '%s\n' "$action $squash $action! $msg_content"
 				used="$used$squash "
 			fi
 		done <"$1.sq"
@@ -724,296 +638,159 @@ rearrange_squash () {
 	rm -f "$1.sq" "$1.rearranged"
 }
 
-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 "$1" in
-	--no-verify)
-		OK_TO_SKIP_PRE_REBASE=yes
-		;;
-	--verify)
-		OK_TO_SKIP_PRE_REBASE=
-		;;
-	--continue)
-		is_standalone "$@" || usage
-		get_saved_options
-		comment_for_reflog continue
-
-		test -d "$DOTEST" || die "No interactive rebase running"
-
-		# Sanity check
-		git rev-parse --verify HEAD >/dev/null ||
-			die "Cannot read HEAD"
-		git update-index --ignore-submodules --refresh &&
-			git diff-files --quiet --ignore-submodules ||
-			die "Working tree is dirty"
-
-		# do we have anything to commit?
-		if git diff-index --cached --quiet --ignore-submodules HEAD --
+case "$action" in
+continue)
+	# do we have anything to commit?
+	if git diff-index --cached --quiet --ignore-submodules HEAD --
+	then
+		: Nothing to commit -- skip this
+	else
+		. "$author_script" ||
+			die "Cannot find the author identity"
+		current_head=
+		if test -f "$amend"
 		then
-			: Nothing to commit -- skip this
-		else
-			. "$AUTHOR_SCRIPT" ||
-				die "Cannot find the author identity"
-			amend=
-			if test -f "$AMEND"
-			then
-				amend=$(git rev-parse --verify HEAD)
-				test "$amend" = $(cat "$AMEND") ||
-				die "\
+			current_head=$(git rev-parse --verify HEAD)
+			test "$current_head" = $(cat "$amend") ||
+			die "\
 You have uncommitted changes in your working tree. Please, commit them
 first and then run 'git rebase --continue' again."
-				git reset --soft HEAD^ ||
-				die "Cannot rewind the HEAD"
-			fi
-			do_with_author git commit --no-verify -F "$MSG" -e || {
-				test -n "$amend" && git reset --soft $amend
-				die "Could not commit staged changes."
-			}
+			git reset --soft HEAD^ ||
+			die "Cannot rewind the HEAD"
 		fi
+		do_with_author git commit --no-verify -F "$msg" -e || {
+			test -n "$current_head" && git reset --soft $current_head
+			die "Could not commit staged changes."
+		}
+	fi
 
-		record_in_rewritten "$(cat "$DOTEST"/stopped-sha)"
-
-		require_clean_work_tree "rebase"
-		do_rest
-		;;
-	--abort)
-		is_standalone "$@" || usage
-		get_saved_options
-		comment_for_reflog abort
-
-		git rerere clear
-		test -d "$DOTEST" || die "No interactive rebase running"
-
-		HEADNAME=$(cat "$DOTEST"/head-name)
-		HEAD=$(cat "$DOTEST"/head)
-		case $HEADNAME in
-		refs/*)
-			git symbolic-ref HEAD $HEADNAME
-			;;
-		esac &&
-		output git reset --hard $HEAD &&
-		rm -rf "$DOTEST"
-		exit
-		;;
-	--skip)
-		is_standalone "$@" || usage
-		get_saved_options
-		comment_for_reflog skip
-
-		git rerere clear
-		test -d "$DOTEST" || die "No interactive rebase running"
-
-		output git reset --hard && do_rest
-		;;
-	-s)
-		case "$#,$1" in
-		*,*=*)
-			STRATEGY="-s "$(expr "z$1" : 'z-[^=]*=\(.*\)') ;;
-		1,*)
-			usage ;;
-		*)
-			STRATEGY="-s $2"
-			shift ;;
-		esac
-		;;
-	-m)
-		# we use merge anyway
-		;;
-	-v)
-		VERBOSE=t
-		;;
-	-p)
-		PRESERVE_MERGES=t
-		;;
-	-i)
-		# yeah, we know
-		;;
-	--no-ff)
-		NEVER_FF=t
-		;;
-	--root)
-		REBASE_ROOT=t
-		;;
-	--autosquash)
-		AUTOSQUASH=t
-		;;
-	--no-autosquash)
-		AUTOSQUASH=
-		;;
-	--onto)
-		shift
-		ONTO=$(parse_onto "$1") ||
-			die "Does not point to a valid commit: $1"
-		;;
-	--)
-		shift
-		test -z "$REBASE_ROOT" -a $# -ge 1 -a $# -le 2 ||
-		test ! -z "$REBASE_ROOT" -a $# -le 1 || usage
-		test -d "$DOTEST" &&
-			die "Interactive rebase already started"
-
-		git var GIT_COMMITTER_IDENT >/dev/null ||
-			die "You need to set your committer info first"
+	record_in_rewritten "$(cat "$state_dir"/stopped-sha)"
 
-		if test -z "$REBASE_ROOT"
-		then
-			UPSTREAM_ARG="$1"
-			UPSTREAM=$(git rev-parse --verify "$1") || die "Invalid base"
-			test -z "$ONTO" && ONTO=$UPSTREAM
-			shift
-		else
-			UPSTREAM=
-			UPSTREAM_ARG=--root
-			test -z "$ONTO" &&
-				die "You must specify --onto when using --root"
-		fi
-		run_pre_rebase_hook "$UPSTREAM_ARG" "$@"
+	require_clean_work_tree "rebase"
+	do_rest
+	;;
+skip)
+	git rerere clear
 
-		comment_for_reflog start
+	do_rest
+	;;
+esac
 
-		require_clean_work_tree "rebase" "Please commit or stash them."
+git var GIT_COMMITTER_IDENT >/dev/null ||
+	die "You need to set your committer info first"
 
-		if test ! -z "$1"
-		then
-			output git checkout "$1" -- ||
-				die "Could not checkout $1"
-		fi
+comment_for_reflog start
 
-		HEAD=$(git rev-parse --verify HEAD) || die "No HEAD?"
-		mkdir "$DOTEST" || die "Could not create temporary $DOTEST"
+if test ! -z "$switch_to"
+then
+	output git checkout "$switch_to" -- ||
+		die "Could not checkout $switch_to"
+fi
 
-		: > "$DOTEST"/interactive || die "Could not mark as interactive"
-		git symbolic-ref HEAD > "$DOTEST"/head-name 2> /dev/null ||
-			echo "detached HEAD" > "$DOTEST"/head-name
+orig_head=$(git rev-parse --verify HEAD) || die "No HEAD?"
+mkdir "$state_dir" || die "Could not create temporary $state_dir"
 
-		echo $HEAD > "$DOTEST"/head
-		case "$REBASE_ROOT" in
-		'')
-			rm -f "$DOTEST"/rebase-root ;;
-		*)
-			: >"$DOTEST"/rebase-root ;;
-		esac
-		echo $ONTO > "$DOTEST"/onto
-		test -z "$STRATEGY" || echo "$STRATEGY" > "$DOTEST"/strategy
-		test t = "$VERBOSE" && : > "$DOTEST"/verbose
-		if test t = "$PRESERVE_MERGES"
-		then
-			if test -z "$REBASE_ROOT"
-			then
-				mkdir "$REWRITTEN" &&
-				for c in $(git merge-base --all $HEAD $UPSTREAM)
-				do
-					echo $ONTO > "$REWRITTEN"/$c ||
-						die "Could not init rewritten commits"
-				done
-			else
-				mkdir "$REWRITTEN" &&
-				echo $ONTO > "$REWRITTEN"/root ||
-					die "Could not init rewritten commits"
-			fi
-			# No cherry-pick because our first pass is to determine
-			# parents to rewrite and skipping dropped commits would
-			# prematurely end our probe
-			MERGES_OPTION=
-			first_after_upstream="$(git rev-list --reverse --first-parent $UPSTREAM..$HEAD | head -n 1)"
-		else
-			MERGES_OPTION="--no-merges --cherry-pick"
-		fi
-
-		SHORTHEAD=$(git rev-parse --short $HEAD)
-		SHORTONTO=$(git rev-parse --short $ONTO)
-		if test -z "$REBASE_ROOT"
-			# this is now equivalent to ! -z "$UPSTREAM"
-		then
-			SHORTUPSTREAM=$(git rev-parse --short $UPSTREAM)
-			REVISIONS=$UPSTREAM...$HEAD
-			SHORTREVISIONS=$SHORTUPSTREAM..$SHORTHEAD
-		else
-			REVISIONS=$ONTO...$HEAD
-			SHORTREVISIONS=$SHORTHEAD
-		fi
-		git rev-list $MERGES_OPTION --pretty=oneline --abbrev-commit \
-			--abbrev=7 --reverse --left-right --topo-order \
-			$REVISIONS | \
-			sed -n "s/^>//p" |
-		while read -r shortsha1 rest
+: > "$state_dir"/interactive || die "Could not mark as interactive"
+write_basic_state
+if test t = "$preserve_merges"
+then
+	if test -z "$rebase_root"
+	then
+		mkdir "$rewritten" &&
+		for c in $(git merge-base --all $orig_head $upstream)
 		do
-			if test t != "$PRESERVE_MERGES"
-			then
-				printf '%s\n' "pick $shortsha1 $rest" >> "$TODO"
-			else
-				sha1=$(git rev-parse $shortsha1)
-				if test -z "$REBASE_ROOT"
-				then
-					preserve=t
-					for p in $(git rev-list --parents -1 $sha1 | cut -d' ' -s -f2-)
-					do
-						if test -f "$REWRITTEN"/$p -a \( $p != $ONTO -o $sha1 = $first_after_upstream \)
-						then
-							preserve=f
-						fi
-					done
-				else
-					preserve=f
-				fi
-				if test f = "$preserve"
-				then
-					touch "$REWRITTEN"/$sha1
-					printf '%s\n' "pick $shortsha1 $rest" >> "$TODO"
-				fi
-			fi
+			echo $onto > "$rewritten"/$c ||
+				die "Could not init rewritten commits"
 		done
-
-		# Watch for commits that been dropped by --cherry-pick
-		if test t = "$PRESERVE_MERGES"
+	else
+		mkdir "$rewritten" &&
+		echo $onto > "$rewritten"/root ||
+			die "Could not init rewritten commits"
+	fi
+	# No cherry-pick because our first pass is to determine
+	# parents to rewrite and skipping dropped commits would
+	# prematurely end our probe
+	merges_option=
+	first_after_upstream="$(git rev-list --reverse --first-parent $upstream..$orig_head | head -n 1)"
+else
+	merges_option="--no-merges --cherry-pick"
+fi
+
+shorthead=$(git rev-parse --short $orig_head)
+shortonto=$(git rev-parse --short $onto)
+if test -z "$rebase_root"
+	# this is now equivalent to ! -z "$upstream"
+then
+	shortupstream=$(git rev-parse --short $upstream)
+	revisions=$upstream...$orig_head
+	shortrevisions=$shortupstream..$shorthead
+else
+	revisions=$onto...$orig_head
+	shortrevisions=$shorthead
+fi
+git rev-list $merges_option --pretty=oneline --abbrev-commit \
+	--abbrev=7 --reverse --left-right --topo-order \
+	$revisions | \
+	sed -n "s/^>//p" |
+while read -r shortsha1 rest
+do
+	if test t != "$preserve_merges"
+	then
+		printf '%s\n' "pick $shortsha1 $rest" >> "$todo"
+	else
+		sha1=$(git rev-parse $shortsha1)
+		if test -z "$rebase_root"
 		then
-			mkdir "$DROPPED"
-			# Save all non-cherry-picked changes
-			git rev-list $REVISIONS --left-right --cherry-pick | \
-				sed -n "s/^>//p" > "$DOTEST"/not-cherry-picks
-			# Now all commits and note which ones are missing in
-			# not-cherry-picks and hence being dropped
-			git rev-list $REVISIONS |
-			while read rev
+			preserve=t
+			for p in $(git rev-list --parents -1 $sha1 | cut -d' ' -s -f2-)
 			do
-				if test -f "$REWRITTEN"/$rev -a "$(sane_grep "$rev" "$DOTEST"/not-cherry-picks)" = ""
+				if test -f "$rewritten"/$p -a \( $p != $onto -o $sha1 = $first_after_upstream \)
 				then
-					# Use -f2 because if rev-list is telling us this commit is
-					# not worthwhile, we don't want to track its multiple heads,
-					# just the history of its first-parent for others that will
-					# be rebasing on top of it
-					git rev-list --parents -1 $rev | cut -d' ' -s -f2 > "$DROPPED"/$rev
-					short=$(git rev-list -1 --abbrev-commit --abbrev=7 $rev)
-					sane_grep -v "^[a-z][a-z]* $short" <"$TODO" > "${TODO}2" ; mv "${TODO}2" "$TODO"
-					rm "$REWRITTEN"/$rev
+					preserve=f
 				fi
 			done
+		else
+			preserve=f
+		fi
+		if test f = "$preserve"
+		then
+			touch "$rewritten"/$sha1
+			printf '%s\n' "pick $shortsha1 $rest" >> "$todo"
 		fi
+	fi
+done
 
-		test -s "$TODO" || echo noop >> "$TODO"
-		test -n "$AUTOSQUASH" && rearrange_squash "$TODO"
-		cat >> "$TODO" << EOF
+# Watch for commits that been dropped by --cherry-pick
+if test t = "$preserve_merges"
+then
+	mkdir "$dropped"
+	# Save all non-cherry-picked changes
+	git rev-list $revisions --left-right --cherry-pick | \
+		sed -n "s/^>//p" > "$state_dir"/not-cherry-picks
+	# Now all commits and note which ones are missing in
+	# not-cherry-picks and hence being dropped
+	git rev-list $revisions |
+	while read rev
+	do
+		if test -f "$rewritten"/$rev -a "$(sane_grep "$rev" "$state_dir"/not-cherry-picks)" = ""
+		then
+			# Use -f2 because if rev-list is telling us this commit is
+			# not worthwhile, we don't want to track its multiple heads,
+			# just the history of its first-parent for others that will
+			# be rebasing on top of it
+			git rev-list --parents -1 $rev | cut -d' ' -s -f2 > "$dropped"/$rev
+			short=$(git rev-list -1 --abbrev-commit --abbrev=7 $rev)
+			sane_grep -v "^[a-z][a-z]* $short" <"$todo" > "${todo}2" ; mv "${todo}2" "$todo"
+			rm "$rewritten"/$rev
+		fi
+	done
+fi
+
+test -s "$todo" || echo noop >> "$todo"
+test -n "$autosquash" && rearrange_squash "$todo"
+cat >> "$todo" << EOF
 
-# Rebase $SHORTREVISIONS onto $SHORTONTO
+# Rebase $shortrevisions onto $shortonto
 #
 # Commands:
 #  p, pick = use commit
@@ -1028,22 +805,18 @@ first and then run 'git rebase --continue' again."
 #
 EOF
 
-		has_action "$TODO" ||
-			die_abort "Nothing to do"
+has_action "$todo" ||
+	die_abort "Nothing to do"
 
-		cp "$TODO" "$TODO".backup
-		git_editor "$TODO" ||
-			die_abort "Could not execute editor"
+cp "$todo" "$todo".backup
+git_editor "$todo" ||
+	die_abort "Could not execute editor"
 
-		has_action "$TODO" ||
-			die_abort "Nothing to do"
+has_action "$todo" ||
+	die_abort "Nothing to do"
 
-		test -d "$REWRITTEN" || test -n "$NEVER_FF" || skip_unnecessary_picks
+test -d "$rewritten" || test -n "$force_rebase" || skip_unnecessary_picks
 
-		output git checkout $ONTO || die_abort "could not detach HEAD"
-		git update-ref ORIG_HEAD $HEAD
-		do_rest
-		;;
-	esac
-	shift
-done
+output git checkout $onto || die_abort "could not detach HEAD"
+git update-ref ORIG_HEAD $orig_head
+do_rest
diff --git a/git-rebase--merge.sh b/git-rebase--merge.sh
new file mode 100644
index 0000000000..26afc75cc7
--- /dev/null
+++ b/git-rebase--merge.sh
@@ -0,0 +1,151 @@
+#!/bin/sh
+#
+# Copyright (c) 2010 Junio C Hamano.
+#
+
+. git-sh-setup
+
+prec=4
+
+read_state () {
+	onto_name=$(cat "$state_dir"/onto_name) &&
+	end=$(cat "$state_dir"/end) &&
+	msgnum=$(cat "$state_dir"/msgnum)
+}
+
+continue_merge () {
+	test -d "$state_dir" || die "$state_dir directory does not exist"
+
+	unmerged=$(git ls-files -u)
+	if test -n "$unmerged"
+	then
+		echo "You still have unmerged paths in your index"
+		echo "did you forget to use git add?"
+		die "$resolvemsg"
+	fi
+
+	cmt=`cat "$state_dir/current"`
+	if ! git diff-index --quiet --ignore-submodules HEAD --
+	then
+		if ! git commit --no-verify -C "$cmt"
+		then
+			echo "Commit failed, please do not call \"git commit\""
+			echo "directly, but instead do one of the following: "
+			die "$resolvemsg"
+		fi
+		if test -z "$GIT_QUIET"
+		then
+			printf "Committed: %0${prec}d " $msgnum
+		fi
+		echo "$cmt $(git rev-parse HEAD^0)" >> "$state_dir/rewritten"
+	else
+		if test -z "$GIT_QUIET"
+		then
+			printf "Already applied: %0${prec}d " $msgnum
+		fi
+	fi
+	test -z "$GIT_QUIET" &&
+	GIT_PAGER='' git log --format=%s -1 "$cmt"
+
+	# onto the next patch:
+	msgnum=$(($msgnum + 1))
+	echo "$msgnum" >"$state_dir/msgnum"
+}
+
+call_merge () {
+	cmt="$(cat "$state_dir/cmt.$1")"
+	echo "$cmt" > "$state_dir/current"
+	hd=$(git rev-parse --verify HEAD)
+	cmt_name=$(git symbolic-ref HEAD 2> /dev/null || echo HEAD)
+	msgnum=$(cat "$state_dir/msgnum")
+	eval GITHEAD_$cmt='"${cmt_name##refs/heads/}~$(($end - $msgnum))"'
+	eval GITHEAD_$hd='$onto_name'
+	export GITHEAD_$cmt GITHEAD_$hd
+	if test -n "$GIT_QUIET"
+	then
+		GIT_MERGE_VERBOSITY=1 && export GIT_MERGE_VERBOSITY
+	fi
+	test -z "$strategy" && strategy=recursive
+	eval 'git-merge-$strategy' $strategy_opts '"$cmt^" -- "$hd" "$cmt"'
+	rv=$?
+	case "$rv" in
+	0)
+		unset GITHEAD_$cmt GITHEAD_$hd
+		return
+		;;
+	1)
+		git rerere $allow_rerere_autoupdate
+		die "$resolvemsg"
+		;;
+	2)
+		echo "Strategy: $strategy failed, try another" 1>&2
+		die "$resolvemsg"
+		;;
+	*)
+		die "Unknown exit code ($rv) from command:" \
+			"git-merge-$strategy $cmt^ -- HEAD $cmt"
+		;;
+	esac
+}
+
+finish_rb_merge () {
+	move_to_original_branch
+	git notes copy --for-rewrite=rebase < "$state_dir"/rewritten
+	if test -x "$GIT_DIR"/hooks/post-rewrite &&
+		test -s "$state_dir"/rewritten; then
+		"$GIT_DIR"/hooks/post-rewrite rebase < "$state_dir"/rewritten
+	fi
+	rm -r "$state_dir"
+	say All done.
+}
+
+case "$action" in
+continue)
+	read_state
+	continue_merge
+	while test "$msgnum" -le "$end"
+	do
+		call_merge "$msgnum"
+		continue_merge
+	done
+	finish_rb_merge
+	exit
+	;;
+skip)
+	read_state
+	git rerere clear
+	msgnum=$(($msgnum + 1))
+	while test "$msgnum" -le "$end"
+	do
+		call_merge "$msgnum"
+		continue_merge
+	done
+	finish_rb_merge
+	exit
+	;;
+esac
+
+mkdir -p "$state_dir"
+echo "$onto_name" > "$state_dir/onto_name"
+write_basic_state
+
+msgnum=0
+for cmt in `git rev-list --reverse --no-merges "$revisions"`
+do
+	msgnum=$(($msgnum + 1))
+	echo "$cmt" > "$state_dir/cmt.$msgnum"
+done
+
+echo 1 >"$state_dir/msgnum"
+echo $msgnum >"$state_dir/end"
+
+end=$msgnum
+msgnum=1
+
+while test "$msgnum" -le "$end"
+do
+	call_merge "$msgnum"
+	continue_merge
+done
+
+finish_rb_merge
diff --git a/git-rebase.sh b/git-rebase.sh
index cbb0ea90ed..7a54bfc618 100755
--- a/git-rebase.sh
+++ b/git-rebase.sh
@@ -3,7 +3,7 @@
 # Copyright (c) 2005 Junio C Hamano.
 #
 
-USAGE='[--interactive | -i] [-v] [--force-rebase | -f] [--no-ff] [--onto <newbase>] (<upstream>|--root) [<branch>] [--quiet | -q]'
+USAGE='[--interactive | -i] [-v] [--force-rebase | -f] [--no-ff] [--onto <newbase>] [<upstream>|--root] [<branch>] [--quiet | -q]'
 LONG_USAGE='git-rebase replaces <branch> with a new branch of the
 same name.  When the --onto option is provided the new branch starts
 out with a HEAD equal to <newbase>, otherwise it is equal to <upstream>
@@ -28,7 +28,39 @@ Example:       git-rebase master~1 topic
 '
 
 SUBDIRECTORY_OK=Yes
-OPTIONS_SPEC=
+OPTIONS_KEEPDASHDASH=
+OPTIONS_SPEC="\
+git rebase [-i] [options] [--onto <newbase>] [<upstream>] [<branch>]
+git rebase [-i] [options] --onto <newbase> --root [<branch>]
+git-rebase [-i] --continue | --abort | --skip
+--
+ Available options are
+v,verbose!         display a diffstat of what changed upstream
+q,quiet!           be quiet. implies --no-stat
+onto=!             rebase onto given branch instead of upstream
+p,preserve-merges! try to recreate merges instead of ignoring them
+s,strategy=!       use the given merge strategy
+no-ff!             cherry-pick all commits, even if unchanged
+m,merge!           use merging strategies to rebase
+i,interactive!     let the user edit the list of commits to rebase
+f,force-rebase!    force rebase even if branch is up to date
+X,strategy-option=! pass the argument through to the merge strategy
+stat!              display a diffstat of what changed upstream
+n,no-stat!         do not show diffstat of what changed upstream
+verify             allow pre-rebase hook to run
+rerere-autoupdate  allow rerere to update index with resolved conflicts
+root!              rebase all reachable commits up to the root(s)
+autosquash         move commits that begin with squash!/fixup! under -i
+committer-date-is-author-date! passed to 'git am'
+ignore-date!       passed to 'git am'
+whitespace=!       passed to 'git apply'
+ignore-whitespace! passed to 'git apply'
+C=!                passed to 'git apply'
+ Actions:
+continue!          continue rebasing process
+abort!             abort rebasing process and restore original branch
+skip!              skip current patch and continue rebasing process
+"
 . git-sh-setup
 set_reflog_action rebase
 require_work_tree
@@ -36,18 +68,18 @@ cd_to_toplevel
 
 LF='
 '
-OK_TO_SKIP_PRE_REBASE=
-RESOLVEMSG="
+ok_to_skip_pre_rebase=
+resolvemsg="
 When you have resolved this problem run \"git rebase --continue\".
 If you would prefer to skip this patch, instead run \"git rebase --skip\".
 To restore the original branch and stop rebasing run \"git rebase --abort\".
 "
-unset newbase
-strategy=recursive
+unset onto
+strategy=
 strategy_opts=
 do_merge=
-dotest="$GIT_DIR"/rebase-merge
-prec=4
+merge_dir="$GIT_DIR"/rebase-merge
+apply_dir="$GIT_DIR"/rebase-apply
 verbose=
 diffstat=
 test "$(git config --bool rebase.stat)" = true && diffstat=t
@@ -55,92 +87,67 @@ git_am_opt=
 rebase_root=
 force_rebase=
 allow_rerere_autoupdate=
-
-continue_merge () {
-	test -n "$prev_head" || die "prev_head must be defined"
-	test -d "$dotest" || die "$dotest directory does not exist"
-
-	unmerged=$(git ls-files -u)
-	if test -n "$unmerged"
-	then
-		echo "You still have unmerged paths in your index"
-		echo "did you forget to use git add?"
-		die "$RESOLVEMSG"
-	fi
-
-	cmt=`cat "$dotest/current"`
-	if ! git diff-index --quiet --ignore-submodules HEAD --
+# Non-empty if a rebase was in progress when 'git rebase' was invoked
+in_progress=
+# One of {am, merge, interactive}
+type=
+# One of {"$GIT_DIR"/rebase-apply, "$GIT_DIR"/rebase-merge}
+state_dir=
+# One of {'', continue, skip, abort}, as parsed from command line
+action=
+preserve_merges=
+autosquash=
+test "$(git config --bool rebase.autosquash)" = "true" && autosquash=t
+
+read_basic_state () {
+	head_name=$(cat "$state_dir"/head-name) &&
+	onto=$(cat "$state_dir"/onto) &&
+	# We always write to orig-head, but interactive rebase used to write to
+	# head. Fall back to reading from head to cover for the case that the
+	# user upgraded git with an ongoing interactive rebase.
+	if test -f "$state_dir"/orig-head
 	then
-		if ! git commit --no-verify -C "$cmt"
-		then
-			echo "Commit failed, please do not call \"git commit\""
-			echo "directly, but instead do one of the following: "
-			die "$RESOLVEMSG"
-		fi
-		if test -z "$GIT_QUIET"
-		then
-			printf "Committed: %0${prec}d " $msgnum
-		fi
-		echo "$cmt $(git rev-parse HEAD^0)" >> "$dotest/rewritten"
+		orig_head=$(cat "$state_dir"/orig-head)
 	else
-		if test -z "$GIT_QUIET"
-		then
-			printf "Already applied: %0${prec}d " $msgnum
-		fi
-	fi
-	test -z "$GIT_QUIET" &&
-	GIT_PAGER='' git log --format=%s -1 "$cmt"
-
-	prev_head=`git rev-parse HEAD^0`
-	# save the resulting commit so we can read-tree on it later
-	echo "$prev_head" > "$dotest/prev_head"
+		orig_head=$(cat "$state_dir"/head)
+	fi &&
+	GIT_QUIET=$(cat "$state_dir"/quiet) &&
+	test -f "$state_dir"/verbose && verbose=t
+	test -f "$state_dir"/strategy && strategy="$(cat "$state_dir"/strategy)"
+	test -f "$state_dir"/strategy_opts &&
+		strategy_opts="$(cat "$state_dir"/strategy_opts)"
+	test -f "$state_dir"/allow_rerere_autoupdate &&
+		allow_rerere_autoupdate="$(cat "$state_dir"/allow_rerere_autoupdate)"
+}
 
-	# onto the next patch:
-	msgnum=$(($msgnum + 1))
-	echo "$msgnum" >"$dotest/msgnum"
+write_basic_state () {
+	echo "$head_name" > "$state_dir"/head-name &&
+	echo "$onto" > "$state_dir"/onto &&
+	echo "$orig_head" > "$state_dir"/orig-head &&
+	echo "$GIT_QUIET" > "$state_dir"/quiet &&
+	test t = "$verbose" && : > "$state_dir"/verbose
+	test -n "$strategy" && echo "$strategy" > "$state_dir"/strategy
+	test -n "$strategy_opts" && echo "$strategy_opts" > \
+		"$state_dir"/strategy_opts
+	test -n "$allow_rerere_autoupdate" && echo "$allow_rerere_autoupdate" > \
+		"$state_dir"/allow_rerere_autoupdate
 }
 
-call_merge () {
-	cmt="$(cat "$dotest/cmt.$1")"
-	echo "$cmt" > "$dotest/current"
-	hd=$(git rev-parse --verify HEAD)
-	cmt_name=$(git symbolic-ref HEAD 2> /dev/null || echo HEAD)
-	msgnum=$(cat "$dotest/msgnum")
-	end=$(cat "$dotest/end")
-	eval GITHEAD_$cmt='"${cmt_name##refs/heads/}~$(($end - $msgnum))"'
-	eval GITHEAD_$hd='$(cat "$dotest/onto_name")'
-	export GITHEAD_$cmt GITHEAD_$hd
-	if test -n "$GIT_QUIET"
-	then
-		GIT_MERGE_VERBOSITY=1 && export GIT_MERGE_VERBOSITY
-	fi
-	eval 'git-merge-$strategy' $strategy_opts '"$cmt^" -- "$hd" "$cmt"'
-	rv=$?
-	case "$rv" in
-	0)
-		unset GITHEAD_$cmt GITHEAD_$hd
-		return
-		;;
-	1)
-		git rerere $allow_rerere_autoupdate
-		die "$RESOLVEMSG"
-		;;
-	2)
-		echo "Strategy: $rv $strategy failed, try another" 1>&2
-		die "$RESOLVEMSG"
+output () {
+	case "$verbose" in
+	'')
+		output=$("$@" 2>&1 )
+		status=$?
+		test $status != 0 && printf "%s\n" "$output"
+		return $status
 		;;
 	*)
-		die "Unknown exit code ($rv) from command:" \
-			"git-merge-$strategy $cmt^ -- HEAD $cmt"
+		"$@"
 		;;
 	esac
 }
 
 move_to_original_branch () {
-	test -z "$head_name" &&
-		head_name="$(cat "$dotest"/head-name)" &&
-		onto="$(cat "$dotest"/onto)" &&
-		orig_head="$(cat "$dotest"/orig-head)"
 	case "$head_name" in
 	refs/*)
 		message="rebase finished: $head_name onto $onto"
@@ -152,42 +159,16 @@ move_to_original_branch () {
 	esac
 }
 
-finish_rb_merge () {
-	move_to_original_branch
-	git notes copy --for-rewrite=rebase < "$dotest"/rewritten
-	if test -x "$GIT_DIR"/hooks/post-rewrite &&
-		test -s "$dotest"/rewritten; then
-		"$GIT_DIR"/hooks/post-rewrite rebase < "$dotest"/rewritten
-	fi
-	rm -r "$dotest"
-	say All done.
-}
-
-is_interactive () {
-	while test $# != 0
-	do
-		case "$1" in
-			-i|--interactive)
-				interactive_rebase=explicit
-				break
-			;;
-			-p|--preserve-merges)
-				interactive_rebase=implied
-			;;
-		esac
-		shift
-	done
-
+run_specific_rebase () {
 	if [ "$interactive_rebase" = implied ]; then
 		GIT_EDITOR=:
 		export GIT_EDITOR
 	fi
-
-	test -n "$interactive_rebase" || test -f "$dotest"/interactive
+	. git-rebase--$type
 }
 
 run_pre_rebase_hook () {
-	if test -z "$OK_TO_SKIP_PRE_REBASE" &&
+	if test -z "$ok_to_skip_pre_rebase" &&
 	   test -x "$GIT_DIR/hooks/pre-rebase"
 	then
 		"$GIT_DIR/hooks/pre-rebase" ${1+"$@"} ||
@@ -195,163 +176,94 @@ run_pre_rebase_hook () {
 	fi
 }
 
-test -f "$GIT_DIR"/rebase-apply/applying &&
+test -f "$apply_dir"/applying &&
 	die 'It looks like git-am is in progress. Cannot rebase.'
 
-is_interactive "$@" && exec git-rebase--interactive "$@"
+if test -d "$apply_dir"
+then
+	type=am
+	state_dir="$apply_dir"
+elif test -d "$merge_dir"
+then
+	if test -f "$merge_dir"/interactive
+	then
+		type=interactive
+		interactive_rebase=explicit
+	else
+		type=merge
+	fi
+	state_dir="$merge_dir"
+fi
+test -n "$type" && in_progress=t
 
+total_argc=$#
 while test $# != 0
 do
 	case "$1" in
 	--no-verify)
-		OK_TO_SKIP_PRE_REBASE=yes
+		ok_to_skip_pre_rebase=yes
 		;;
 	--verify)
-		OK_TO_SKIP_PRE_REBASE=
-		;;
-	--continue)
-		test -d "$dotest" -o -d "$GIT_DIR"/rebase-apply ||
-			die "No rebase in progress?"
-
-		git update-index --ignore-submodules --refresh &&
-		git diff-files --quiet --ignore-submodules || {
-			echo "You must edit all merge conflicts and then"
-			echo "mark them as resolved using git add"
-			exit 1
-		}
-		if test -d "$dotest"
-		then
-			prev_head=$(cat "$dotest/prev_head")
-			end=$(cat "$dotest/end")
-			msgnum=$(cat "$dotest/msgnum")
-			onto=$(cat "$dotest/onto")
-			GIT_QUIET=$(cat "$dotest/quiet")
-			continue_merge
-			while test "$msgnum" -le "$end"
-			do
-				call_merge "$msgnum"
-				continue_merge
-			done
-			finish_rb_merge
-			exit
-		fi
-		head_name=$(cat "$GIT_DIR"/rebase-apply/head-name) &&
-		onto=$(cat "$GIT_DIR"/rebase-apply/onto) &&
-		orig_head=$(cat "$GIT_DIR"/rebase-apply/orig-head) &&
-		GIT_QUIET=$(cat "$GIT_DIR"/rebase-apply/quiet)
-		git am --resolved --3way --resolvemsg="$RESOLVEMSG" &&
-		move_to_original_branch
-		exit
+		ok_to_skip_pre_rebase=
 		;;
-	--skip)
-		test -d "$dotest" -o -d "$GIT_DIR"/rebase-apply ||
-			die "No rebase in progress?"
-
-		git reset --hard HEAD || exit $?
-		if test -d "$dotest"
-		then
-			git rerere clear
-			prev_head=$(cat "$dotest/prev_head")
-			end=$(cat "$dotest/end")
-			msgnum=$(cat "$dotest/msgnum")
-			msgnum=$(($msgnum + 1))
-			onto=$(cat "$dotest/onto")
-			GIT_QUIET=$(cat "$dotest/quiet")
-			while test "$msgnum" -le "$end"
-			do
-				call_merge "$msgnum"
-				continue_merge
-			done
-			finish_rb_merge
-			exit
-		fi
-		head_name=$(cat "$GIT_DIR"/rebase-apply/head-name) &&
-		onto=$(cat "$GIT_DIR"/rebase-apply/onto) &&
-		orig_head=$(cat "$GIT_DIR"/rebase-apply/orig-head) &&
-		GIT_QUIET=$(cat "$GIT_DIR"/rebase-apply/quiet)
-		git am -3 --skip --resolvemsg="$RESOLVEMSG" &&
-		move_to_original_branch
-		exit
-		;;
-	--abort)
-		test -d "$dotest" -o -d "$GIT_DIR"/rebase-apply ||
-			die "No rebase in progress?"
-
-		git rerere clear
-
-		test -d "$dotest" || dotest="$GIT_DIR"/rebase-apply
-
-		head_name="$(cat "$dotest"/head-name)" &&
-		case "$head_name" in
-		refs/*)
-			git symbolic-ref HEAD $head_name ||
-			die "Could not move back to $head_name"
-			;;
-		esac
-		git reset --hard $(cat "$dotest/orig-head")
-		rm -r "$dotest"
-		exit
+	--continue|--skip|--abort)
+		test $total_argc -eq 2 || usage
+		action=${1##--}
 		;;
 	--onto)
 		test 2 -le "$#" || usage
-		newbase="$2"
+		onto="$2"
 		shift
 		;;
-	-M|-m|--m|--me|--mer|--merg|--merge)
+	-i)
+		interactive_rebase=explicit
+		;;
+	-p)
+		preserve_merges=t
+		test -z "$interactive_rebase" && interactive_rebase=implied
+		;;
+	--autosquash)
+		autosquash=t
+		;;
+	--no-autosquash)
+		autosquash=
+		;;
+	-M|-m)
 		do_merge=t
 		;;
-	-X*|--strategy-option*)
-		case "$#,$1" in
-		1,-X|1,--strategy-option)
-			usage ;;
-		*,-X|*,--strategy-option)
-			newopt="$2"
-			shift ;;
-		*,--strategy-option=*)
-			newopt="$(expr " $1" : ' --strategy-option=\(.*\)')" ;;
-		*,-X*)
-			newopt="$(expr " $1" : ' -X\(.*\)')" ;;
-		1,*)
-			usage ;;
-		esac
-		strategy_opts="$strategy_opts $(git rev-parse --sq-quote "--$newopt")"
+	-X)
+		shift
+		strategy_opts="$strategy_opts $(git rev-parse --sq-quote "--$1")"
 		do_merge=t
+		test -z "$strategy" && strategy=recursive
 		;;
-	-s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
-		--strateg=*|--strategy=*|\
-	-s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
-		case "$#,$1" in
-		*,*=*)
-			strategy=`expr "z$1" : 'z-[^=]*=\(.*\)'` ;;
-		1,*)
-			usage ;;
-		*)
-			strategy="$2"
-			shift ;;
-		esac
+	-s)
+		shift
+		strategy="$1"
 		do_merge=t
 		;;
-	-n|--no-stat)
+	-n)
 		diffstat=
 		;;
 	--stat)
 		diffstat=t
 		;;
-	-v|--verbose)
+	-v)
 		verbose=t
 		diffstat=t
 		GIT_QUIET=
 		;;
-	-q|--quiet)
+	-q)
 		GIT_QUIET=t
 		git_am_opt="$git_am_opt -q"
 		verbose=
 		diffstat=
 		;;
-	--whitespace=*)
-		git_am_opt="$git_am_opt $1"
+	--whitespace)
+		shift
+		git_am_opt="$git_am_opt --whitespace=$1"
 		case "$1" in
-		--whitespace=fix|--whitespace=strip)
+		fix|strip)
 			force_rebase=t
 			;;
 		esac
@@ -363,22 +275,21 @@ do
 		git_am_opt="$git_am_opt $1"
 		force_rebase=t
 		;;
-	-C*)
-		git_am_opt="$git_am_opt $1"
+	-C)
+		shift
+		git_am_opt="$git_am_opt -C$1"
 		;;
 	--root)
 		rebase_root=t
 		;;
-	-f|--f|--fo|--for|--forc|--force|--force-r|--force-re|--force-reb|--force-reba|--force-rebas|--force-rebase|--no-ff)
+	-f|--no-ff)
 		force_rebase=t
 		;;
 	--rerere-autoupdate|--no-rerere-autoupdate)
 		allow_rerere_autoupdate="$1"
 		;;
-	-*)
-		usage
-		;;
-	*)
+	--)
+		shift
 		break
 		;;
 	esac
@@ -386,58 +297,106 @@ do
 done
 test $# -gt 2 && usage
 
-if test $# -eq 0 && test -z "$rebase_root"
+if test -n "$action"
 then
-	test -d "$dotest" -o -d "$GIT_DIR"/rebase-apply || usage
-	test -d "$dotest" -o -f "$GIT_DIR"/rebase-apply/rebasing &&
-		die 'A rebase is in progress, try --continue, --skip or --abort.'
+	test -z "$in_progress" && die "No rebase in progress?"
+	# Only interactive rebase uses detailed reflog messages
+	if test "$type" = interactive && test "$GIT_REFLOG_ACTION" = rebase
+	then
+		GIT_REFLOG_ACTION="rebase -i ($action)"
+		export GIT_REFLOG_ACTION
+	fi
 fi
 
-# Make sure we do not have $GIT_DIR/rebase-apply
-if test -z "$do_merge"
+case "$action" in
+continue)
+	# Sanity check
+	git rev-parse --verify HEAD >/dev/null ||
+		die "Cannot read HEAD"
+	git update-index --ignore-submodules --refresh &&
+	git diff-files --quiet --ignore-submodules || {
+		echo "You must edit all merge conflicts and then"
+		echo "mark them as resolved using git add"
+		exit 1
+	}
+	read_basic_state
+	run_specific_rebase
+	;;
+skip)
+	output git reset --hard HEAD || exit $?
+	read_basic_state
+	run_specific_rebase
+	;;
+abort)
+	git rerere clear
+	read_basic_state
+	case "$head_name" in
+	refs/*)
+		git symbolic-ref HEAD $head_name ||
+		die "Could not move back to $head_name"
+		;;
+	esac
+	output git reset --hard $orig_head
+	rm -r "$state_dir"
+	exit
+	;;
+esac
+
+# Make sure no rebase is in progress
+if test -n "$in_progress"
 then
-	if mkdir "$GIT_DIR"/rebase-apply 2>/dev/null
-	then
-		rmdir "$GIT_DIR"/rebase-apply
-	else
-		echo >&2 '
-It seems that I cannot create a rebase-apply directory, and
-I wonder if you are in the middle of patch application or another
-rebase.  If that is not the case, please
-	rm -fr '"$GIT_DIR"'/rebase-apply
+	die '
+It seems that there is already a '"${state_dir##*/}"' directory, and
+I wonder if you are in the middle of another rebase.  If that is the
+case, please try
+	git rebase (--continue | --abort | --skip)
+If that is not the case, please
+	rm -fr '"$state_dir"'
 and run me again.  I am stopping in case you still have something
 valuable there.'
-		exit 1
-	fi
-else
-	if test -d "$dotest"
-	then
-		die "previous rebase directory $dotest still exists." \
-			'Try git rebase (--continue | --abort | --skip)'
-	fi
 fi
 
-require_clean_work_tree "rebase" "Please commit or stash them."
+if test -n "$interactive_rebase"
+then
+	type=interactive
+	state_dir="$merge_dir"
+elif test -n "$do_merge"
+then
+	type=merge
+	state_dir="$merge_dir"
+else
+	type=am
+	state_dir="$apply_dir"
+fi
 
 if test -z "$rebase_root"
 then
-	# The upstream head must be given.  Make sure it is valid.
-	upstream_name="$1"
-	shift
+	case "$#" in
+	0)
+		if ! upstream_name=$(git rev-parse --symbolic-full-name \
+			--verify -q @{upstream} 2>/dev/null)
+		then
+			. git-parse-remote
+			error_on_missing_default_upstream "rebase" "rebase" \
+				"against" "git rebase <upstream branch>"
+		fi
+		;;
+	*)	upstream_name="$1"
+		shift
+		;;
+	esac
 	upstream=`git rev-parse --verify "${upstream_name}^0"` ||
 	die "invalid upstream $upstream_name"
-	unset root_flag
 	upstream_arg="$upstream_name"
 else
-	test -z "$newbase" && die "--root must be used with --onto"
+	test -z "$onto" && die "You must specify --onto when using --root"
 	unset upstream_name
 	unset upstream
-	root_flag="--root"
-	upstream_arg="$root_flag"
+	upstream_arg=--root
 fi
 
 # Make sure the branch to rebase onto is valid.
-onto_name=${newbase-"$upstream_name"}
+onto_name=${onto-"$upstream_name"}
 case "$onto_name" in
 *...*)
 	if	left=${onto_name%...*} right=${onto_name#*...} &&
@@ -456,13 +415,11 @@ case "$onto_name" in
 	fi
 	;;
 *)
-	onto=$(git rev-parse --verify "${onto_name}^0") || exit
+	onto=$(git rev-parse --verify "${onto_name}^0") ||
+	die "Does not point to a valid commit: $1"
 	;;
 esac
 
-# If a hook exists, give it a chance to interrupt
-run_pre_rebase_hook "$upstream_arg" "$@"
-
 # If the branch to rebase is given, that is the branch we will rebase
 # $branch_name -- branch being rebased, or HEAD (already detached)
 # $orig_head -- commit object name of tip of the branch before rebasing
@@ -475,10 +432,10 @@ case "$#" in
 	switch_to="$1"
 
 	if git show-ref --verify --quiet -- "refs/heads/$1" &&
-	   branch=$(git rev-parse -q --verify "refs/heads/$1")
+	   orig_head=$(git rev-parse -q --verify "refs/heads/$1")
 	then
 		head_name="refs/heads/$1"
-	elif branch=$(git rev-parse -q --verify "$1")
+	elif orig_head=$(git rev-parse -q --verify "$1")
 	then
 		head_name="detached HEAD"
 	else
@@ -496,20 +453,23 @@ case "$#" in
 		head_name="detached HEAD"
 		branch_name=HEAD ;# detached
 	fi
-	branch=$(git rev-parse --verify "${branch_name}^0") || exit
+	orig_head=$(git rev-parse --verify "${branch_name}^0") || exit
 	;;
 esac
-orig_head=$branch
 
-# Now we are rebasing commits $upstream..$branch (or with --root,
-# everything leading up to $branch) on top of $onto
+require_clean_work_tree "rebase" "Please commit or stash them."
+
+# Now we are rebasing commits $upstream..$orig_head (or with --root,
+# everything leading up to $orig_head) on top of $onto
 
 # Check if we are already based on $onto with linear history,
-# but this should be done only when upstream and onto are the same.
-mb=$(git merge-base "$onto" "$branch")
-if test "$upstream" = "$onto" && test "$mb" = "$onto" &&
+# but this should be done only when upstream and onto are the same
+# and if this is not an interactive rebase.
+mb=$(git merge-base "$onto" "$orig_head")
+if test "$type" != interactive && test "$upstream" = "$onto" &&
+	test "$mb" = "$onto" &&
 	# linear history?
-	! (git rev-list --parents "$onto".."$branch" | sane_grep " .* ") > /dev/null
+	! (git rev-list --parents "$onto".."$orig_head" | sane_grep " .* ") > /dev/null
 then
 	if test -z "$force_rebase"
 	then
@@ -522,10 +482,8 @@ then
 	fi
 fi
 
-# Detach HEAD and reset the tree
-say "First, rewinding head to replay your work on top of it..."
-git checkout -q "$onto^0" || die "could not detach HEAD"
-git update-ref ORIG_HEAD $branch
+# If a hook exists, give it a chance to interrupt
+run_pre_rebase_hook "$upstream_arg" "$@"
 
 if test -n "$diffstat"
 then
@@ -537,9 +495,16 @@ then
 	GIT_PAGER='' git diff --stat --summary "$mb" "$onto"
 fi
 
+test "$type" = interactive && run_specific_rebase
+
+# Detach HEAD and reset the tree
+say "First, rewinding head to replay your work on top of it..."
+git checkout -q "$onto^0" || die "could not detach HEAD"
+git update-ref ORIG_HEAD $orig_head
+
 # If the $onto is a proper descendant of the tip of the branch, then
 # we just fast-forwarded.
-if test "$mb" = "$branch"
+if test "$mb" = "$orig_head"
 then
 	say "Fast-forwarded $branch_name to $onto_name."
 	move_to_original_branch
@@ -553,51 +518,4 @@ else
 	revisions="$upstream..$orig_head"
 fi
 
-if test -z "$do_merge"
-then
-	git format-patch -k --stdout --full-index --ignore-if-in-upstream \
-		--src-prefix=a/ --dst-prefix=b/ \
-		--no-renames $root_flag "$revisions" |
-	git am $git_am_opt --rebasing --resolvemsg="$RESOLVEMSG" &&
-	move_to_original_branch
-	ret=$?
-	test 0 != $ret -a -d "$GIT_DIR"/rebase-apply &&
-		echo $head_name > "$GIT_DIR"/rebase-apply/head-name &&
-		echo $onto > "$GIT_DIR"/rebase-apply/onto &&
-		echo $orig_head > "$GIT_DIR"/rebase-apply/orig-head &&
-		echo "$GIT_QUIET" > "$GIT_DIR"/rebase-apply/quiet
-	exit $ret
-fi
-
-# start doing a rebase with git-merge
-# this is rename-aware if the recursive (default) strategy is used
-
-mkdir -p "$dotest"
-echo "$onto" > "$dotest/onto"
-echo "$onto_name" > "$dotest/onto_name"
-prev_head=$orig_head
-echo "$prev_head" > "$dotest/prev_head"
-echo "$orig_head" > "$dotest/orig-head"
-echo "$head_name" > "$dotest/head-name"
-echo "$GIT_QUIET" > "$dotest/quiet"
-
-msgnum=0
-for cmt in `git rev-list --reverse --no-merges "$revisions"`
-do
-	msgnum=$(($msgnum + 1))
-	echo "$cmt" > "$dotest/cmt.$msgnum"
-done
-
-echo 1 >"$dotest/msgnum"
-echo $msgnum >"$dotest/end"
-
-end=$msgnum
-msgnum=1
-
-while test "$msgnum" -le "$end"
-do
-	call_merge "$msgnum"
-	continue_merge
-done
-
-finish_rb_merge
+run_specific_rebase
diff --git a/t/t3400-rebase.sh b/t/t3400-rebase.sh
index 349eebd542..6eaecec906 100755
--- a/t/t3400-rebase.sh
+++ b/t/t3400-rebase.sh
@@ -158,15 +158,24 @@ test_expect_success 'Show verbose error when HEAD could not be detached' '
 '
 rm -f B
 
-test_expect_success 'dump usage when upstream arg is missing' '
-	git checkout -b usage topic &&
-	test_must_fail git rebase 2>error1 &&
-	grep "[Uu]sage" error1 &&
-	test_must_fail git rebase --abort 2>error2 &&
-	grep "No rebase in progress" error2 &&
-	test_must_fail git rebase --onto master 2>error3 &&
-	grep "[Uu]sage" error3 &&
-	! grep "can.t shift" error3
+test_expect_success 'fail when upstream arg is missing and not on branch' '
+	git checkout topic &&
+	test_must_fail git rebase >output.out &&
+	grep "You are not currently on a branch" output.out
+'
+
+test_expect_success 'fail when upstream arg is missing and not configured' '
+	git checkout -b no-config topic &&
+	test_must_fail git rebase >output.out &&
+	grep "branch.no-config.merge" output.out
+'
+
+test_expect_success 'default to @{upstream} when upstream arg is missing' '
+	git checkout -b default topic &&
+	git config branch.default.remote .
+	git config branch.default.merge refs/heads/master
+	git rebase &&
+	test "$(git rev-parse default~1)" = "$(git rev-parse master)"
 '
 
 test_expect_success 'rebase -q is quiet' '
diff --git a/t/t3403-rebase-skip.sh b/t/t3403-rebase-skip.sh
index 64446e3db3..826500bd18 100755
--- a/t/t3403-rebase-skip.sh
+++ b/t/t3403-rebase-skip.sh
@@ -35,6 +35,11 @@ test_expect_success 'rebase with git am -3 (default)' '
 	test_must_fail git rebase master
 '
 
+test_expect_success 'rebase --skip can not be used with other options' '
+	test_must_fail git rebase -v --skip &&
+	test_must_fail git rebase --skip -v
+'
+
 test_expect_success 'rebase --skip with am -3' '
 	git rebase --skip
 	'
diff --git a/t/t3407-rebase-abort.sh b/t/t3407-rebase-abort.sh
index e573dc845b..a6a6c40a98 100755
--- a/t/t3407-rebase-abort.sh
+++ b/t/t3407-rebase-abort.sh
@@ -84,6 +84,16 @@ testrebase() {
 		test_cmp reflog_before reflog_after &&
 		rm reflog_before reflog_after
 	'
+
+	test_expect_success 'rebase --abort can not be used with other options' '
+		cd "$work_dir" &&
+		# Clean up the state from the previous one
+		git reset --hard pre-rebase &&
+		test_must_fail git rebase$type master &&
+		test_must_fail git rebase -v --abort &&
+		test_must_fail git rebase --abort -v &&
+		git rebase --abort
+	'
 }
 
 testrebase "" .git/rebase-apply
diff --git a/t/t3418-rebase-continue.sh b/t/t3418-rebase-continue.sh
index 3b0d27350e..1e855cdae5 100755
--- a/t/t3418-rebase-continue.sh
+++ b/t/t3418-rebase-continue.sh
@@ -40,4 +40,59 @@ test_expect_success 'non-interactive rebase --continue works with touched file'
 	git rebase --continue
 '
 
+test_expect_success 'rebase --continue can not be used with other options' '
+	test_must_fail git rebase -v --continue &&
+	test_must_fail git rebase --continue -v
+'
+
+test_expect_success 'rebase --continue remembers merge strategy and options' '
+	rm -fr .git/rebase-* &&
+	git reset --hard commit-new-file-F2-on-topic-branch &&
+	test_commit "commit-new-file-F3-on-topic-branch" F3 32 &&
+	test_when_finished "rm -fr test-bin funny.was.run" &&
+	mkdir test-bin &&
+	cat >test-bin/git-merge-funny <<-EOF
+	#!$SHELL_PATH
+	case "\$1" in --opt) ;; *) exit 2 ;; esac
+	shift &&
+	>funny.was.run &&
+	exec git merge-recursive "\$@"
+	EOF
+	chmod +x test-bin/git-merge-funny &&
+	(
+		PATH=./test-bin:$PATH
+		test_must_fail git rebase -s funny -Xopt master topic
+	) &&
+	test -f funny.was.run &&
+	rm funny.was.run &&
+	echo "Resolved" >F2 &&
+	git add F2 &&
+	(
+		PATH=./test-bin:$PATH
+		git rebase --continue
+	) &&
+	test -f funny.was.run
+'
+
+test_expect_success 'rebase --continue remembers --rerere-autoupdate' '
+	rm -fr .git/rebase-* &&
+	git reset --hard commit-new-file-F3-on-topic-branch &&
+	git checkout master
+	test_commit "commit-new-file-F3" F3 3 &&
+	git config rerere.enabled true &&
+	test_must_fail git rebase -m master topic &&
+	echo "Resolved" >F2 &&
+	git add F2 &&
+	test_must_fail git rebase --continue &&
+	echo "Resolved" >F3 &&
+	git add F3 &&
+	git rebase --continue &&
+	git reset --hard topic@{1} &&
+	test_must_fail git rebase -m --rerere-autoupdate master &&
+	test "$(cat F2)" = "Resolved" &&
+	test_must_fail git rebase --continue &&
+	test "$(cat F3)" = "Resolved" &&
+	git rebase --continue
+'
+
 test_done