git sequencer prototype

@@ -42,11 +42,6 @@ STRATEGY=
 ONTO=
 VERBOSE=
 
-GIT_CHERRY_PICK_HELP="  After resolving the conflicts,
-mark the corrected paths with 'git add <paths>', and
-run 'git rebase --continue'"
-export GIT_CHERRY_PICK_HELP
-
 warn () {
 	echo "$*" >&2
 }

@@ -74,48 +69,6 @@ require_clean_work_tree () {
 	die "Working tree is dirty"
 }
 
-ORIG_REFLOG_ACTION="$GIT_REFLOG_ACTION"
-
-comment_for_reflog () {
-	case "$ORIG_REFLOG_ACTION" in
-	''|rebase*)
-		GIT_REFLOG_ACTION="rebase -i ($1)"
-		export GIT_REFLOG_ACTION
-		;;
-	esac
-}
-
-last_count=
-mark_action_done () {
-	sed -e 1q < "$TODO" >> "$DONE"
-	sed -e 1d < "$TODO" >> "$TODO".new
-	mv -f "$TODO".new "$TODO"
-	count=$(grep -c '^[^#]' < "$DONE")
-	total=$(($count+$(grep -c '^[^#]' < "$TODO")))
-	if test "$last_count" != "$count"
-	then
-		last_count=$count
-		printf "Rebasing (%d/%d)\r" $count $total
-		test -z "$VERBOSE" || echo
-	fi
-}
-
-make_patch () {
-	parent_sha1=$(git rev-parse --verify "$1"^) ||
-		die "Cannot get patch for $1^"
-	git diff-tree -p "$parent_sha1".."$1" > "$DOTEST"/patch
-	test -f "$DOTEST"/message ||
-		git cat-file commit "$1" | sed "1,/^$/d" > "$DOTEST"/message
-	test -f "$DOTEST"/author-script ||
-		get_author_ident_from_commit "$1" > "$DOTEST"/author-script
-}
-
-die_with_patch () {
-	make_patch "$1"
-	git rerere
-	die "$2"
-}
-
 die_abort () {
 	rm -rf "$DOTEST"
 	die "$1"

@@ -125,48 +78,20 @@ has_action () {
 	grep '^[^#]' "$1" >/dev/null
 }
 
-pick_one () {
-	no_ff=
-	case "$1" in -n) sha1=$2; no_ff=t ;; *) sha1=$1 ;; esac
-	output git rev-parse --verify $sha1 || die "Invalid commit name: $sha1"
-	test -d "$REWRITTEN" &&
-		pick_one_preserving_merges "$@" && return
-	parent_sha1=$(git rev-parse --verify $sha1^) ||
-		die "Could not get the parent of $sha1"
-	current_sha1=$(git rev-parse --verify HEAD)
-	if test "$no_ff$current_sha1" = "$parent_sha1"; then
-		output git reset --hard $sha1
-		test "a$1" = a-n && output git reset --soft $current_sha1
-		sha1=$(git rev-parse --short $sha1)
-		output warn Fast forward to $sha1
-	else
-		output git cherry-pick "$@"
-	fi
-}
-
-pick_one_preserving_merges () {
-	case "$1" in -n) sha1=$2 ;; *) sha1=$1 ;; esac
+create_todo_preserving_merges () {
+	shortsha1=$sha1
 	sha1=$(git rev-parse $sha1)
 
-	if test -f "$DOTEST"/current-commit
-	then
-		current_commit=$(cat "$DOTEST"/current-commit) &&
-		git rev-parse HEAD > "$REWRITTEN"/$current_commit &&
-		rm "$DOTEST"/current-commit ||
-		die "Cannot write current commit's replacement sha1"
-	fi
-
-	# rewrite parents; if none were rewritten, we can fast-forward.
-	fast_forward=t
 	preserve=t
 	new_parents=
+	first_parent=
 	for p in $(git rev-list --parents -1 $sha1 | cut -d' ' -f2-)
 	do
+		# check if we've already seen this parent
 		if test -f "$REWRITTEN"/$p
 		then
 			preserve=f
 			new_p=$(cat "$REWRITTEN"/$p)
-			test $p != $new_p && fast_forward=f
 			case "$new_parents" in
 			*$new_p*)
 				;; # do nothing; that parent is already there

@@ -177,185 +102,46 @@ pick_one_preserving_merges () {
 		else
 			new_parents="$new_parents $p"
 		fi
+		test -n "$first_parent" || first_parent=$p
 	done
-	case $fast_forward in
-	t)
-		output warn "Fast forward to $sha1"
-		test $preserve = f || echo $sha1 > "$REWRITTEN"/$sha1
-		;;
-	f)
-		test "a$1" = a-n && die "Refusing to squash a merge: $sha1"
-
-		first_parent=$(expr "$new_parents" : ' \([^ ]*\)')
-		# detach HEAD to current parent
-		output git checkout $first_parent 2> /dev/null ||
-			die "Cannot move HEAD to $first_parent"
-
-		echo $sha1 > "$DOTEST"/current-commit
-		case "$new_parents" in
-		' '*' '*)
-			# redo merge
-			author_script=$(get_author_ident_from_commit $sha1)
-			eval "$author_script"
-			msg="$(git cat-file commit $sha1 | sed -e '1,/^$/d')"
-			# No point in merging the first parent, that's HEAD
-			new_parents=${new_parents# $first_parent}
-			if ! GIT_AUTHOR_NAME="$GIT_AUTHOR_NAME" \
-				GIT_AUTHOR_EMAIL="$GIT_AUTHOR_EMAIL" \
-				GIT_AUTHOR_DATE="$GIT_AUTHOR_DATE" \
-				output git merge $STRATEGY -m "$msg" \
-					$new_parents
-			then
-				git rerere
-				printf "%s\n" "$msg" > "$GIT_DIR"/MERGE_MSG
-				die Error redoing merge $sha1
-			fi
-			;;
-		*)
-			output git cherry-pick "$@" ||
-				die_with_patch $sha1 "Could not pick $sha1"
-			;;
-		esac
-		;;
-	esac
-}
+	# We do not have parent, so ignore this commit
+	test t = $preserve && return
 
-nth_string () {
-	case "$1" in
-	*1[0-9]|*[04-9]) echo "$1"th;;
-	*1) echo "$1"st;;
-	*2) echo "$1"nd;;
-	*3) echo "$1"rd;;
-	esac
-}
+	# We always write a mark, because we do not know if there will
+	# be a "reset" or "merge"
+	# Filter the unneeded marks out afterwards.
+	echo "mark :$mark"
+	mark=$(($mark+1))
 
-make_squash_message () {
-	if test -f "$SQUASH_MSG"; then
-		COUNT=$(($(sed -n "s/^# This is [^0-9]*\([1-9][0-9]*\).*/\1/p" \
-			< "$SQUASH_MSG" | sed -ne '$p')+1))
-		echo "# This is a combination of $COUNT commits."
-		sed -e 1d -e '2,/^./{
-			/^$/d
-		}' <"$SQUASH_MSG"
-	else
-		COUNT=2
-		echo "# This is a combination of two commits."
-		echo "# The first commit's message is:"
-		echo
-		git cat-file commit HEAD | sed -e '1,/^$/d'
-	fi
-	echo
-	echo "# This is the $(nth_string $COUNT) commit message:"
-	echo
-	git cat-file commit $1 | sed -e '1,/^$/d'
-}
+	new_first_parent=$(expr "$new_parents" : ' \([^ ]*\)')
 
-peek_next_command () {
-	sed -n "1s/ .*$//p" < "$TODO"
-}
+	# Reset if needed
+	test -z "$first_parent" -o "$first_parent" = $lastsha1 ||
+		echo "reset $new_first_parent"
 
-do_next () {
-	rm -f "$DOTEST"/message "$DOTEST"/author-script \
-		"$DOTEST"/amend || exit
-	read command sha1 rest < "$TODO"
-	case "$command" in
-	'#'*|'')
-		mark_action_done
-		;;
-	pick|p)
-		comment_for_reflog pick
+	echo ":$mark" > "$REWRITTEN"/$sha1
 
-		mark_action_done
-		pick_one $sha1 ||
-			die_with_patch $sha1 "Could not apply $sha1... $rest"
-		;;
-	edit|e)
-		comment_for_reflog edit
-
-		mark_action_done
-		pick_one $sha1 ||
-			die_with_patch $sha1 "Could not apply $sha1... $rest"
-		make_patch $sha1
-		: > "$DOTEST"/amend
-		warn "Stopped at $sha1... $rest"
-		warn "You can amend the commit now, with"
-		warn
-		warn "	git commit --amend"
-		warn
-		warn "Once you are satisfied with your changes, run"
-		warn
-		warn "	git rebase --continue"
-		warn
-		exit 0
-		;;
-	squash|s)
-		comment_for_reflog squash
-
-		has_action "$DONE" ||
-			die "Cannot 'squash' without a previous commit"
-
-		mark_action_done
-		make_squash_message $sha1 > "$MSG"
-		case "$(peek_next_command)" in
-		squash|s)
-			EDIT_COMMIT=
-			USE_OUTPUT=output
-			cp "$MSG" "$SQUASH_MSG"
-			;;
-		*)
-			EDIT_COMMIT=-e
-			USE_OUTPUT=
-			rm -f "$SQUASH_MSG" || exit
-			;;
-		esac
-
-		failed=f
-		author_script=$(get_author_ident_from_commit HEAD)
-		output git reset --soft HEAD^
-		pick_one -n $sha1 || failed=t
-		echo "$author_script" > "$DOTEST"/author-script
-		if test $failed = f
-		then
-			# This is like --amend, but with a different message
-			eval "$author_script"
-			GIT_AUTHOR_NAME="$GIT_AUTHOR_NAME" \
-			GIT_AUTHOR_EMAIL="$GIT_AUTHOR_EMAIL" \
-			GIT_AUTHOR_DATE="$GIT_AUTHOR_DATE" \
-			$USE_OUTPUT git commit --no-verify -F "$MSG" $EDIT_COMMIT || failed=t
-		fi
-		if test $failed = t
-		then
-			cp "$MSG" "$GIT_DIR"/MERGE_MSG
-			warn
-			warn "Could not apply $sha1... $rest"
-			die_with_patch $sha1 ""
-		fi
+	# Merge or pick
+	case "$new_parents" in
+	' '*' '*)
+		new_parents=${new_parents# $new_first_parent}
+		printf 'merge%s -C %s%s\t%s\n' "$STRATEGY" \
+			"$shortsha1" "$new_parents" "$rest"
 		;;
 	*)
-		warn "Unknown command: $command $sha1 $rest"
-		die_with_patch $sha1 "Please fix this in the file $TODO."
+		printf 'pick %s\t%s\n' "$shortsha1" "$rest"
 		;;
 	esac
-	test -s "$TODO" && return
 
-	comment_for_reflog finish &&
+	lastsha1="$sha1"
+	return 0
+}
+
+update_refs_and_exit () {
 	HEADNAME=$(cat "$DOTEST"/head-name) &&
 	OLDHEAD=$(cat "$DOTEST"/head) &&
 	SHORTONTO=$(git rev-parse --short $(cat "$DOTEST"/onto)) &&
-	if test -d "$REWRITTEN"
-	then
-		test -f "$DOTEST"/current-commit &&
-			current_commit=$(cat "$DOTEST"/current-commit) &&
-			git rev-parse HEAD > "$REWRITTEN"/$current_commit
-		if test -f "$REWRITTEN"/$OLDHEAD
-		then
-			NEWHEAD=$(cat "$REWRITTEN"/$OLDHEAD)
-		else
-			NEWHEAD=$OLDHEAD
-		fi
-	else
-		NEWHEAD=$(git rev-parse HEAD)
-	fi &&
+	NEWHEAD=$(git rev-parse HEAD) &&
 	case $HEADNAME in
 	refs/*)
 		message="$GIT_REFLOG_ACTION: $HEADNAME onto $SHORTONTO)" &&

@@ -373,13 +159,6 @@ do_next () {
 	exit
 }
 
-do_rest () {
-	while :
-	do
-		do_next
-	done
-}
-
 # check if no other options are set
 is_standalone () {
 	test $# -eq 2 -a "$2" = '--' &&

@@ -395,80 +174,47 @@ get_saved_options () {
 	test -f "$DOTEST"/verbose && VERBOSE=t
 }
 
-while test $# != 0
-do
-	case "$1" in
-	--continue)
-		is_standalone "$@" || usage
-		get_saved_options
-		comment_for_reflog continue
-
-		test -d "$DOTEST" || die "No interactive rebase running"
-
-		# Sanity check
-		git rev-parse --verify HEAD >/dev/null ||
-			die "Cannot read HEAD"
-		git update-index --ignore-submodules --refresh &&
-			git diff-files --quiet --ignore-submodules ||
-			die "Working tree is dirty"
-
-		# do we have anything to commit?
-		if git diff-index --cached --quiet --ignore-submodules HEAD --
+run_sequencer () {
+	git sequencer --caller='git rebase -i|--abort|--continue|--skip' "$@"
+	case "$?" in
+	0)
+		if test "$1" = --abort
 		then
-			: Nothing to commit -- skip this
+			rm -rf "$DOTEST"
+			exit
 		else
-			. "$DOTEST"/author-script ||
-				die "Cannot find the author identity"
-			if test -f "$DOTEST"/amend
-			then
-				git reset --soft HEAD^ ||
-				die "Cannot rewind the HEAD"
-			fi
-			export GIT_AUTHOR_NAME GIT_AUTHOR_EMAIL GIT_AUTHOR_DATE &&
-			git commit --no-verify -F "$DOTEST"/message -e ||
-			die "Could not commit staged changes."
+			update_refs_and_exit
 		fi
-
-		require_clean_work_tree
-		do_rest
 		;;
-	--abort)
-		is_standalone "$@" || 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
+	2)
+		# pause
+		exit 0
 		;;
-	--skip)
-		is_standalone "$@" || usage
-		get_saved_options
-		comment_for_reflog skip
-
-		git rerere clear
-		test -d "$DOTEST" || die "No interactive rebase running"
+	3)
+		# conflict
+		exit 1
+		;;
+	*)
+		die_abort 'git-sequencer died unexpected.'
+		;;
+	esac
+}
 
-		output git reset --hard && do_rest
+while test $# != 0
+do
+	case "$1" in
+	--abort|--continue|--skip)
+		is_standalone "$@" || usage
+		run_sequencer "$1"
 		;;
 	-s)
 		case "$#,$1" in
 		*,*=*)
-			STRATEGY="-s "$(expr "z$1" : 'z-[^=]*=\(.*\)') ;;
+			STRATEGY=" -s "$(expr "z$1" : 'z-[^=]*=\(.*\)') ;;
 		1,*)
 			usage ;;
 		*)
-			STRATEGY="-s $2"
+			STRATEGY=" -s $2"
 			shift ;;
 		esac
 		;;

@@ -494,12 +240,12 @@ do
 		test $# -eq 1 -o $# -eq 2 || usage
 		test -d "$DOTEST" &&
 			die "Interactive rebase already started"
+		git sequencer --status >/dev/null 2>&1 &&
+			die "Sequencer already started. Cannot run rebase."
 
 		git var GIT_COMMITTER_IDENT >/dev/null ||
 			die "You need to set your committer info first"
 
-		comment_for_reflog start
-
 		require_clean_work_tree
 
 		UPSTREAM=$(git rev-parse --verify "$1") || die "Invalid base"

@@ -516,42 +262,72 @@ do
 		HEAD=$(git rev-parse --verify HEAD) || die "No HEAD?"
 		mkdir "$DOTEST" || die "Could not create temporary $DOTEST"
 
-		: > "$DOTEST"/interactive || die "Could not mark as interactive"
+		: > "$DOTEST"/interactive || die_abort "Could not mark as interactive"
 		git symbolic-ref HEAD > "$DOTEST"/head-name 2> /dev/null ||
 			echo "detached HEAD" > "$DOTEST"/head-name
 
 		echo $HEAD > "$DOTEST"/head
-		echo $UPSTREAM > "$DOTEST"/upstream
 		echo $ONTO > "$DOTEST"/onto
 		test -z "$STRATEGY" || echo "$STRATEGY" > "$DOTEST"/strategy
 		test t = "$VERBOSE" && : > "$DOTEST"/verbose
 		if test t = "$PRESERVE_MERGES"
 		then
+			lastsha1=
 			# $REWRITTEN contains 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.)
+			# reachable on the way between $UPSTREAM and $HEAD.
+			# The filename is the SHA1 of the old value and the
+			# content is the SHA1 or :mark of the new one.
 			mkdir "$REWRITTEN" &&
 			for c in $(git merge-base --all $HEAD $UPSTREAM)
 			do
+				test -n "$lastsha1" || lastsha1=$c
 				echo $ONTO > "$REWRITTEN"/$c ||
 					die "Could not init rewritten commits"
 			done
-			MERGES_OPTION=
-		else
-			MERGES_OPTION=--no-merges
+			git rev-list --abbrev-commit --abbrev=7 \
+				--pretty=format:"%m%h	# %s" --topo-order \
+				--reverse --cherry-pick $UPSTREAM...$HEAD | \
+				sed -n -e "s/^>//p" > "$DOTEST"/commit-list
+
+			mark=0
+			while read -r sha1 rest
+			do
+				create_todo_preserving_merges
+			done < "$DOTEST"/commit-list > "$TODO"
+
+			# We now have more "mark :..." lines than needed.
+			# Remove the unused.  This is just a step to keep
+			# the list clean.
+			keep_marks=$(sed -e "/^mark :/d" <"$TODO" |
+				sed -n -e 's/^[^#]* :\([0-9][0-9]*\).*$/:\1:/p')
+			while read -r line
+			do
+				case "$line" in
+				'mark :'*)
+					case "$keep_marks " in
+					*${line#mark }:*)
+						echo "$line"
+						;;
+					esac
+					;;
+				*)
+					printf '%s\n' "$line"
+					;;
+				esac
+			done < "$TODO" > "$TODO".new
+			mv "$TODO".new "$TODO"
+		fi
+		if test -z "$PRESERVE_MERGES"
+		then
+			git rev-list --no-merges --abbrev-commit --abbrev=7 \
+				--pretty=format:"%mpick %h	# %s" \
+				--reverse --cherry-pick $UPSTREAM...$HEAD | \
+				sed -n -e "s/^>//p" > "$TODO"
 		fi
 
 		SHORTUPSTREAM=$(git rev-parse --short $UPSTREAM)
 		SHORTHEAD=$(git rev-parse --short $HEAD)
 		SHORTONTO=$(git rev-parse --short $ONTO)
-		git rev-list $MERGES_OPTION --pretty=oneline --abbrev-commit \
-			--abbrev=7 --reverse --left-right --cherry-pick \
-			$UPSTREAM...$HEAD | \
-			sed -n "s/^>/pick /p" > "$TODO"
 		cat >> "$TODO" << EOF
 
 # Rebase $SHORTUPSTREAM..$SHORTHEAD onto $SHORTONTO

@@ -577,7 +353,7 @@ EOF
 			die_abort "Nothing to do"
 
 		git update-ref ORIG_HEAD $HEAD
-		output git checkout $ONTO && do_rest
+		run_sequencer --onto "$ONTO" "$TODO"
 		;;
 	esac
 	shift

@@ -159,19 +159,19 @@ test_expect_success 'stop on conflicting pick' '
 	git tag new-branch1 &&
 	test_must_fail git rebase -i master &&
 	test "$(git rev-parse HEAD~3)" = "$(git rev-parse master)" &&
-	test_cmp expect .git/rebase-merge/patch &&
 	test_cmp expect2 file1 &&
 	test "$(git-diff --name-status |
 		sed -n -e "/^U/s/^U[^a-z]*//p")" = file1 &&
-	test 4 = $(grep -v "^#" < .git/rebase-merge/done | wc -l) &&
-	test 0 = $(grep -c "^[^#]" < .git/rebase-merge/git-rebase-todo)
+	test 4 = $(grep -v "^#" < .git/sequencer/done | wc -l) &&
+	test 0 = $(grep -c "^[^#]" < .git/sequencer/todo) &&
+	test -d .git/rebase-merge
 '
 
 test_expect_success 'abort' '
 	git rebase --abort &&
 	test $(git rev-parse new-branch1) = $(git rev-parse HEAD) &&
 	test "$(git symbolic-ref -q HEAD)" = "refs/heads/branch1" &&
-	! test -d .git/rebase-merge
+	! test -d .git/sequencer
 '
 
 test_expect_success 'retain authorship' '

@@ -0,0 +1,838 @@
+#!/bin/sh
+#
+# Copyright (c) 2008 Stephan Beyer
+#
+# `setup' is based on t3404* by Johannes Schindelin.
+
+test_description='git sequencer
+
+These are basic usage tests for git sequencer.
+'
+. ./test-lib.sh
+
+# set up two branches like this:
+#
+# A - B - C - D - E
+#   \
+#     F - G - H
+#       \
+#         I
+#
+# where B, D and G touch increment value in file1.
+# The others generate empty file[23456].
+
+SEQDIR=".git/sequencer"
+SEQMARK="refs/sequencer-marks"
+MARKDIR=".git/$SEQMARK"
+
+test_expect_success 'setup' '
+	: >file1 &&
+	git add file1 &&
+	test_tick &&
+	git commit -m "generate empty file1" &&
+	git tag A &&
+	echo 1 >file1 &&
+	test_tick &&
+	git commit -m "write 1 into file1" file1 &&
+	git tag B &&
+	: >file2 &&
+	git add file2 &&
+	test_tick &&
+	git commit -m "generate empty file2" &&
+	git tag C &&
+	echo 2 >file1 &&
+	test_tick &&
+	git commit -m "write 2 into file1" file1 &&
+	git tag D &&
+	: >file3 &&
+	git add file3 &&
+	test_tick &&
+	git commit -m "generate empty file3" &&
+	git tag E &&
+	git checkout -b branch1 A &&
+	: >file4 &&
+	git add file4 &&
+	test_tick &&
+	git commit -m "generate empty file4" &&
+	git tag F &&
+	echo 3 >file1 &&
+	test_tick &&
+	git commit -m "write 3 into file1" file1 &&
+	git tag G &&
+	: >file5 &&
+	git add file5 &&
+	test_tick &&
+	git commit -m "generate empty file5" &&
+	git tag H &&
+	git checkout -b branch2 F &&
+	: >file6 &&
+	git add file6 &&
+	test_tick &&
+	git commit -m "generate empty file6" &&
+	git tag I &&
+	git diff -p --raw C..D >patchD.raw &&
+	git diff -p --raw A..F >patchF.raw &&
+	git format-patch --stdout A..B >patchB &&
+	git format-patch --stdout B..C >patchC &&
+	git format-patch --stdout C..D >patchD &&
+	git format-patch --stdout A..F >patchF &&
+	git format-patch --stdout F..G >patchG
+'
+
+orig_author="$GIT_AUTHOR_NAME <$GIT_AUTHOR_EMAIL>"
+
+# Functions to verify exit status of sequencer.
+# Do not just use "test_must_fail git sequencer ..."!
+expect_fail () {
+	"$@"
+	test $? -eq 1
+}
+expect_continue () {
+	"$@"
+	test $? -eq 2
+}
+expect_conflict () {
+	"$@"
+	test $? -eq 3
+}
+
+
+# Other test helpers:
+
+# Test if commit $1 has author $2
+expect_author () {
+	test "$2" = "$(git cat-file commit "$1" |
+		sed -n -e "s/^author \(.*\)> .*$/\1>/p")"
+}
+
+# Test if commit $1 has commit message in file $2
+# Side effect: overwrites actual
+expect_msg () {
+	git cat-file commit "$1" | sed -e "1,/^$/d" >actual &&
+	test_cmp "$2" actual
+}
+
+# Test that no marks are set.
+no_marks_set () {
+	if test -e "$MARKDIR"
+	then
+		rmdir "$MARKDIR"
+	fi
+}
+
+test_expect_success 'fail on empty TODO from stdin' '
+	expect_fail git sequencer <file6 &&
+	! test -d "$SEQDIR"
+'
+
+# Generate fake editor
+#
+# Simple and practical concept:
+#  We use only a small string identifier for "editor sessions".
+#  Each sessions knows what to do and perhaps defines
+#  which session to choose next.
+echo "#!$SHELL_PATH" >fake-editor.sh
+cat >>fake-editor.sh <<\EOF
+test -f fake-editor-session || exit 1
+#test -t 1 || exit 1
+# This test could be useful, but as the test-lib is not always
+# verbose, this will fail.
+next=ok
+read this <fake-editor-session
+case "$this" in
+commitmsg)
+	echo 'echo 2 >file1'
+	;;
+squashCE)
+	echo 'generate file2 and file3'
+	;;
+squashCI)
+	echo 'generate file2 and file6'
+	next=squashDCE
+	;;
+squashDCE)
+	echo 'generate file2 and file3 and write 2 into file1'
+	next=merge1
+	;;
+merge1)
+	echo 'A typed merge message.'
+	;;
+merge2)
+	test "$(sed -n -e 1p "$1")" = 'test merge' &&
+		echo 'cleanup merge' ||
+		echo error
+	sed -e 1d "$1"
+	;;
+editXXXXXXXXX)
+	printf 'last edited'
+	;;
+edit*)
+	printf 'edited: '
+	cat "$1"
+	next="${this}X"
+	;;
+nochange)
+	cat "$1"
+	;;
+ok|fail)
+	echo '-- THIS IS UNEXPECTED --'
+	next=fail
+	;;
+*)
+	echo 'I do not know.'
+	;;
+esac >"$1".tmp
+mv "$1".tmp "$1"
+echo $next >fake-editor-session
+exit 0
+EOF
+chmod a+x fake-editor.sh
+test_set_editor "$(pwd)/fake-editor.sh"
+
+next_session () {
+	echo "$1" >fake-editor-session
+}
+
+# check if fake-editor-session is ok.
+# If "$1" is set to anything, it will set the
+# next session to "ok", which is nice for
+# test_expect_failure.
+session_ok () {
+	test "ok" = $(cat fake-editor-session)
+	ret=$?
+	test -n "$1" && next_session ok
+	return $ret
+}
+
+
+cat >todotest1 <<EOF
+pick C
+squash E
+ref refs/tags/CE
+EOF
+
+test_expect_success '"pick", "squash", "ref" from stdin' '
+	next_session squashCE &&
+	git sequencer <todotest1 &&
+	! test -d "$SEQDIR" &&
+	session_ok &&
+	test -f file2 &&
+	test -f file3 &&
+	test $(git rev-parse CE) = $(git rev-parse HEAD) &&
+	test $(git rev-parse I) = $(git rev-parse HEAD^)
+'
+
+cat >todotest2 <<EOF
+# This is a test
+
+reset I  # go back to I
+
+EOF
+
+test_expect_success '"reset" from file with comments and blank lines' '
+	git sequencer todotest2 &&
+	session_ok &&
+	test $(git rev-parse I) = $(git rev-parse HEAD)
+'
+
+cat >todotest1 <<EOF
+pick C
+EOF
+
+test_expect_success '--onto <branch> keeps branch' '
+	git checkout -b test-branch A &&
+	git checkout master &&
+	git sequencer --onto test-branch <todotest1 &&
+	session_ok &&
+	test "$(git symbolic-ref -q HEAD)" = "refs/heads/test-branch" &&
+	test "$(git rev-parse test-branch^)" = "$(git rev-parse A)"
+'
+
+test_expect_success '--onto commit (detached HEAD) works' '
+	git sequencer --onto A <todotest1 &&
+	session_ok &&
+	test_must_fail git symbolic-ref -q HEAD &&
+	test "$(git rev-parse HEAD)" = "$(git rev-parse test-branch)"
+'
+
+echo 'pick -R C' >>todotest1
+
+test_expect_success 'pick -R works' '
+	git checkout A &&
+	git sequencer todotest1 &&
+	session_ok &&
+	! test -f file2
+'
+
+mkdir testdir
+cat >testdir/script <<EOF
+#!/bin/sh
+test -s ../file1
+EOF
+chmod 755 testdir/script
+cat >todotest1 <<EOF
+run -- test -s file1  # this will fail
+pick B
+run --dir testdir -- test -s ../file1
+pick D
+run --dir=testdir ./script
+EOF
+
+test_expect_success '"run" insn works' '
+	git checkout A &&
+	expect_conflict git sequencer todotest1 &&
+	: >newfile &&
+	git add newfile &&
+	next_session nochange &&
+	git sequencer --continue &&
+	session_ok &&
+	test -f newfile
+'
+
+echo thisdoesnotexist >>todotest1
+
+test_expect_success 'junk is conflict' '
+	git checkout A &&
+	expect_conflict git sequencer todotest1 &&
+	test -d "$SEQDIR" &&
+	git sequencer --abort &&
+	! test -d "$SEQDIR" &&
+	session_ok &&
+	test $(git rev-parse A) = $(git rev-parse HEAD)
+'
+
+GIT_AUTHOR_NAME="Another 'ant' Thor"
+GIT_AUTHOR_EMAIL="a.thor@example.com"
+GIT_COMMITTER_NAME="Co M Miter"
+GIT_COMMITTER_EMAIL="c.miter@example.com"
+export GIT_AUTHOR_NAME GIT_AUTHOR_EMAIL GIT_COMMITTER_NAME GIT_COMMITTER_EMAIL
+yet_another="Max Min <mm@example.com>"
+
+cat >todotest1 <<EOF
+patch patchB      # write 1 into file1
+patch -k patchC   # generate file2
+patch patchD.raw  # write 2 into file1
+EOF
+
+echo 'write 1 into file1' >expected1
+echo '[PATCH] generate empty file2' >expected2
+echo 'echo 2 >file1' >expected3
+
+test_expect_success '"patch" insn works' '
+	git checkout A &&
+	next_session commitmsg &&
+	git sequencer todotest1 &&
+	! test -d "$SEQDIR" &&
+	session_ok &&
+	test "$(git rev-parse HEAD~3)" = "$(git rev-parse A)" &&
+	test "$(git show HEAD~2:file1)" = "1" &&
+	test -z "$(git show HEAD^:file2)" &&
+	test "$(git show HEAD:file1)" = "2" &&
+	expect_author HEAD~2 "$orig_author" &&
+	expect_author HEAD~1 "$orig_author" &&
+	expect_author HEAD~0 "$GIT_AUTHOR_NAME <$GIT_AUTHOR_EMAIL>" &&
+	expect_msg HEAD~2 expected1 &&
+	expect_msg HEAD~1 expected2 &&
+	expect_msg HEAD~0 expected3
+'
+
+cat >todotest1 <<EOF
+pick B	# write 1 into file1
+pause
+pick C	# generate file2
+EOF
+
+echo 'generate empty file2' >expected1
+echo 'write 1 into file1' >expected2
+
+test_expect_success "pick ; pause insns and --continue works" '
+	git checkout A &&
+	expect_continue git sequencer todotest1 &&
+	session_ok &&
+	echo 5 >file1 &&
+	git add file1 &&
+	next_session nochange &&
+	git sequencer --continue &&
+	test "$(git show HEAD:file1)" = 5 &&
+	test -z "$(git show HEAD:file2)" &&
+	expect_msg HEAD expected1 &&
+	expect_msg HEAD^ expected2 &&
+	session_ok
+'
+
+cat >todotest1 <<EOF
+edit B	# write 1 into file1
+pick C	# generate file2
+EOF
+
+test_expect_success "edit insn and --continue works" '
+	git checkout A &&
+	expect_continue git sequencer todotest1 &&
+	session_ok &&
+	echo 5 >file1 &&
+	git add file1 &&
+	next_session nochange &&
+	git sequencer --continue &&
+	test "$(git show HEAD:file1)" = 5 &&
+	test -z "$(git show HEAD:file2)" &&
+	expect_msg HEAD expected1 &&
+	expect_msg HEAD^ expected2 &&
+	session_ok
+'
+
+cat >todotest1 <<EOF
+patch patchB	# write 1 into file1
+pick H		# generate file5
+mark :1
+patch patchC	# generate file2
+squash I	# generate file6
+patch patchD	# write 2 into file1
+ref refs/tags/CID
+mark :2
+reset :1	# reset to new H
+patch patchD	# write 2 into file1
+squash CE	# generate file2 and file3
+ref refs/tags/DCE
+merge :2	# merge :2 into HEAD
+patch patchF	# generate file4
+EOF
+
+test_expect_success 'all insns work without options' '
+	git checkout A &&
+	next_session squashCI &&
+	no_marks_set &&
+	git sequencer todotest1 &&
+	no_marks_set &&
+	test "$(git show HEAD:file1)" = "2" &&
+	test -z "$(git show HEAD:file2)" &&
+	test -z "$(git show HEAD:file3)" &&
+	test -z "$(git show HEAD:file4)" &&
+	test -z "$(git show HEAD:file5)" &&
+	test -z "$(git show HEAD:file6)" &&
+	echo "$(git rev-parse DCE)" >expected &&
+	echo "$(git rev-parse CID)" >>expected &&
+	git cat-file commit HEAD^ | sed -n -e "s/^parent //p" >actual &&
+	test_cmp expected actual &&
+	session_ok
+'
+
+cat >todotest1 <<EOF
+merge --standard DCE
+EOF
+
+echo "Merge DCE into HEAD" >expected1
+
+test_expect_success 'merge --standard works' '
+	git checkout CID &&
+	git sequencer todotest1 &&
+	expect_msg HEAD expected1 &&
+	session_ok
+'
+
+cat >todotest1 <<EOF
+merge --standard --message="foo" DCE
+EOF
+
+
+test_expect_success 'merge --standard --message="foo" is conflict' '
+	git checkout CID &&
+	expect_conflict git sequencer todotest1 &&
+	git sequencer --abort &&
+	session_ok
+'
+
+for command in 'pick ' 'patch patch' 'squash ' 'merge --standard '
+do
+	cat >todotest1 <<EOF
+patch patchB	# 1 into file1
+${command}G	# 3 into file1
+patch -3 patchF	# empty file4
+EOF
+
+	test_expect_success "conflict test: ${command%% *} and --abort" '
+		git checkout A &&
+		expect_conflict git sequencer todotest1 &&
+		session_ok &&
+		test -d "$SEQDIR" &&
+		git sequencer --abort &&
+		session_ok &&
+		test $(git rev-parse HEAD) = $(git rev-parse A)
+	'
+
+	test_expect_success "conflict test: ${command%% *} and --continue" '
+		git checkout A &&
+		expect_conflict git sequencer todotest1 &&
+		session_ok &&
+		test -d "$SEQDIR" &&
+		## XXX: It would be perfect if we could remove the if
+		{ if test "${command%% *}" != "patch"
+		then grep "^<<<<<<<" file1 ; fi } &&
+		echo 3 >file1 &&
+		git add file1 &&
+		next_session nochange &&
+		git sequencer --continue &&
+		session_ok &&
+		! test -d "$SEQDIR" &&
+		test "$(git show HEAD:file1)" = "3" &&
+		test -f file4
+	'
+
+	test_expect_success "conflict test: ${command%% *} and --skip" '
+		git checkout A &&
+		expect_conflict git sequencer todotest1 &&
+		session_ok &&
+		test -d "$SEQDIR" &&
+		git sequencer --skip &&
+		session_ok &&
+		! test -d "$SEQDIR" &&
+		test "$(git show HEAD:file1)" = "1" &&
+		test -f file4
+	'
+done
+
+echo 'file5-gen' >commitmsg
+
+cat >todotest1 <<EOF
+patch --signoff patchB
+pause
+pick --author="$yet_another" --file="commitmsg" --signoff H
+mark :1
+patch --message="file2-gen" patchC
+squash --signoff --author="$yet_another" I
+pause
+patch --message="echo 2 >file1" patchD
+mark :2
+reset :1
+patch --author="$yet_another" patchD
+squash --signoff --message="generate file[23]" CE
+merge --signoff --message="test merge" --author="$yet_another" :2
+pause
+ref refs/tags/a_merge
+patch --message="Generate file4 and write 23 into it" patchF.raw
+pause
+pick I
+EOF
+
+cat >expected1 <<EOF
+write 1 into file
+
+Signed-off-by: $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL>
+EOF
+
+test_expect_success 'insns work with options and another author 1' '
+	git checkout A &&
+	no_marks_set &&
+
+	# patch --signoff patchB  # write 1 into file1
+	# pause
+	expect_continue git sequencer todotest1 &&
+	test "Signed-off-by: $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL>" = \
+		"$(git cat-file commit HEAD | grep "^Signed-off-by")" &&
+	expect_author HEAD "$orig_author" &&
+	test -d "$SEQDIR" &&
+	session_ok
+'
+
+cat >expected1 <<EOF
+file5-gen
+
+Signed-off-by: $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL>
+EOF
+
+cat >expected2 <<EOF
+file2-gen
+
+generate empty file6
+
+Signed-off-by: $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL>
+EOF
+
+test_expect_success 'insns work with options and another author 2' '
+	: >file7 &&
+	git add file7 &&
+	next_session nochange &&
+	git commit --amend &&
+	session_ok &&
+
+	next_session nochange &&
+	expect_continue git sequencer --continue &&
+	session_ok &&
+
+	# amended commit
+	test "Signed-off-by: $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL>" = \
+		"$(git cat-file commit HEAD^^ | grep "^Signed-off-by")" &&
+	expect_author HEAD^^ "$orig_author" &&
+	test -z "$(git show HEAD:file7)" &&
+
+	# pick --author="$yet_another" --file="commitmsg" --signoff H
+	expect_author HEAD^ "$yet_another" &&
+	expect_msg HEAD^ expected1 &&
+	test -z "$(git show HEAD:file5)" &&
+
+	# mark :1
+	test "$(git rev-parse "$SEQMARK/1")" = "$(git rev-parse HEAD^)" &&
+
+	# patch --message="file2-gen" patchC
+	# squash --signoff --author="$yet_another" I # generate file6
+	# pause
+	test -z "$(git show HEAD:file2)" &&
+	test -z "$(git show HEAD:file6)" &&
+	git ls-files | grep "^file2" &&
+	git ls-files | grep "^file6" &&
+	expect_msg HEAD expected2 &&
+	expect_author HEAD "$yet_another"
+'
+
+echo 'echo 2 >file1' >expected1
+
+cat >expected2 <<EOF
+generate file[23]
+
+Signed-off-by: $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL>
+EOF
+
+cat >expected3 <<EOF
+test merge
+
+Signed-off-by: $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL>
+EOF
+
+cat >expected4 <<EOF
+file1
+file2
+file3
+file5
+file6
+file7
+EOF
+
+test_expect_success 'insns work with options and another author 3' '
+	# do not change anything
+	expect_continue git sequencer --continue &&
+	session_ok &&
+
+	# patch --message="echo 2 >file1" patchD
+	# mark :2
+	commit="$(git rev-parse --verify "$SEQMARK/2")" &&
+	expect_author "$commit" "$orig_author" &&
+	expect_msg "$commit" expected1 &&
+
+	# reset :1
+	# patch --author="$yet_another" patchD # write 2 into file1
+	# squash --signoff --message="generate file[23]" CE
+	expect_author HEAD^ "$yet_another" &&
+	expect_msg HEAD^ expected2 &&
+
+	# merge --signoff --message="test merge" --author="$yet_another" :2
+	# pause
+	expect_author HEAD "$yet_another" &&
+	expect_msg HEAD expected3 &&
+	git ls-files >actual &&
+	test_cmp expected4 actual
+'
+
+cat >expected_merge <<EOF
+cleanup merge
+
+Signed-off-by: $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL>
+EOF
+
+echo 'Generate file4 and write 23 into it' >expected2
+
+test_expect_success 'insns work with options and another author 4' '
+	git rm file5 file6 file7 &&
+	next_session merge2 &&
+	expect_continue git sequencer --continue &&
+	session_ok &&
+
+	# ref refs/tags/a_merge
+	expect_author a_merge "$yet_another" &&
+	expect_msg a_merge expected_merge &&
+
+	# patch --message="Generate file4 and write 23 into it" patchF.raw
+	# pause
+	git ls-files | grep "^file4" &&
+	echo 23 >file4 &&
+	git add file4 &&
+	next_session nochange &&
+	git sequencer --continue &&
+	session_ok &&
+	no_marks_set &&
+	test "$(git show HEAD:file1)" = "2" &&
+	test "$(git show HEAD:file4)" = "23" &&
+	expect_msg HEAD^ expected2 &&
+	expect_author HEAD^ "$GIT_AUTHOR_NAME <$GIT_AUTHOR_EMAIL>" &&
+
+	# pick I
+	test -z "$(git show HEAD:file6)" &&
+	git ls-files | grep "^file6" &&
+	session_ok
+'
+
+# almost the same to test --quiet
+cat >todotest1 <<EOF
+patch patchB
+pick H
+mark :1
+patch patchC
+squash --message="a squash" I
+patch patchD
+mark :2
+reset :1
+patch patchD
+squash --message="another squash" CE
+merge --message="test merge" :2
+pause
+patch patchF
+EOF
+
+test_expect_failure '--quiet works' '
+	git checkout A &&
+	expect_continue git sequencer --quiet todotest1 >actual &&
+	session_ok &&
+	! test -s actual
+'
+
+test_expect_failure '--quiet works on continue' '
+	git sequencer --continue >>actual &&
+	session_ok &&
+	! test -s actual
+'
+
+echo 'merge --strategy=ours --reuse-commit=a_merge branch1 branch2 CE CID' >todotest1
+
+test_expect_success 'merge multiple branches and --reuse-commit works' '
+	git checkout -b merge-multiple master &&
+	git sequencer todotest1 &&
+	session_ok &&
+	expect_msg HEAD expected_merge &&
+	git rev-parse HEAD^ >expected &&
+	git rev-parse branch1 >>expected &&
+	git rev-parse branch2 >>expected &&
+	git rev-parse CE >>expected &&
+	git rev-parse CID >>expected &&
+	git cat-file commit HEAD | sed -n -e "s/^parent //p" >actual &&
+	test_cmp expected actual &&
+	! test -f file6
+'
+
+echo 'pick --mainline=5 merge-multiple' >todotest1
+
+test_expect_success 'pick --mainline works' '
+	git checkout -b mainline CID &&
+	git sequencer todotest1 &&
+	session_ok &&
+	expect_msg HEAD expected_merge &&
+	! test -f file6 &&
+	test -f file3 &&
+	test -f file2 &&
+	test "$(git show HEAD:file1)" = 2
+'
+
+cat >todotest1 <<EOF
+pick C		# file2
+mark :1
+patch patchB	# write 1 into file1
+patch patchD	# write 2 into file1
+pick I		# file6
+squash --message="2 in file1 and file6 exists" --signoff --from :1
+EOF
+
+cat >expected1 <<EOF
+2 in file1 and file6 exists
+
+Signed-off-by: $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL>
+EOF
+
+test_expect_success 'squash --from works' '
+	git checkout A &&
+	git sequencer <todotest1 &&
+	session_ok &&
+	test "$(git rev-parse A)" = "$(git rev-parse HEAD~2)" &&
+	test "$(git show HEAD:file1)" = "2" &&
+	test -z "$(git show HEAD:file6)" &&
+	expect_msg HEAD expected1
+'
+
+cat >todotest1 <<EOF
+patch patchB	# write 1 into file1
+pick H		# generate file5
+mark :1
+patch patchC	# generate file2
+squash --message="file5" I	# generate file6
+patch patchD	# write 2 into file1
+mark :2
+reset :1	# reset to new H
+patch patchD	# write 2 into file1
+squash --message="CE" CE	# generate file2 and file3
+merge --standard :2	# merge :2 into HEAD
+patch patchF	# generate file4
+EOF
+cp todotest1 todotest2
+cat todotest1 | sed -e 's/^\(patch\|pick\|squash\|merge\) /&--edit /' >todotest3
+echo 'squash --message="doesnt work either" --from :1' >>todotest1
+echo 'squash --include-merges --message="stupid" --from :1' >>todotest2
+
+test_expect_success 'squash --from conflicts with merge in between' '
+	git checkout A &&
+	expect_conflict git sequencer todotest1 &&
+	git sequencer --abort &&
+	session_ok &&
+	! test -d "$SEQDIR"
+'
+
+test_expect_success 'squash --include-merges --from succeeds with merge in between' '
+	git checkout A &&
+	git sequencer todotest2 &&
+	session_ok &&
+	test "$(git rev-parse HEAD~3)" = "$(git rev-parse A)"
+'
+
+test_expect_success 'patch|pick|squash|merge --edit works' '
+	git checkout A &&
+	next_session editX &&
+	git sequencer todotest3 &&
+	session_ok
+'
+
+cat >todotest1 <<EOF
+patch patchB
+pause
+EOF
+
+test_expect_success 'batch mode fails on pause insn' '
+	git checkout A &&
+	expect_fail git sequencer --batch todotest1 &&
+	session_ok &&
+	! test -d "$SEQDIR"
+'
+
+cat >todotest1 <<EOF
+patch patchB
+pick G
+EOF
+
+test_expect_success 'batch mode fails on conflict' '
+	git checkout A &&
+	expect_fail git sequencer --batch <todotest1 &&
+	session_ok &&
+	! test -d "$SEQDIR" &&
+	test -z "$(git show HEAD:file1)"
+'
+
+cat >todotest1 <<EOF
+patch patchB
+pause
+EOF
+
+test_expect_success '--caller works' '
+	git checkout A &&
+	expect_continue git sequencer \
+		--caller="this works|abrt||skip" todotest1 &&
+	expect_fail git sequencer --abort &&
+	expect_fail git sequencer --skip &&
+	git sequencer --continue &&
+	session_ok
+'
+
+test_done