patchallow git-am to run in a subdirectory

diff --git a/git-am.sh b/git-am.sh
index 2ecebc4..a2c6fea 100755
--- a/git-am.sh
+++ b/git-am.sh
@@ -2,6 +2,7 @@
 #
 # Copyright (c) 2005, 2006 Junio C Hamano
 
+SUBDIRECTORY_OK=Yes
 OPTIONS_KEEPDASHDASH=
 OPTIONS_SPEC="\
 git-am [options] <mbox>|<Maildir>...
@@ -25,6 +26,7 @@ skip            skip the current patch"
 . git-sh-setup
 set_reflog_action am
 require_work_tree
+cd_to_toplevel
 
 git var GIT_COMMITTER_IDENT >/dev/null || exit
 

diff --git a/git-am.sh b/git-am.sh
index 2ecebc4..a5e0c43 100755
--- a/git-am.sh
+++ b/git-am.sh
@@ -2,6 +2,7 @@
 #
 # Copyright (c) 2005, 2006 Junio C Hamano
 
+SUBDIRECTORY_OK=Yes
 OPTIONS_KEEPDASHDASH=
 OPTIONS_SPEC="\
 git-am [options] <mbox>|<Maildir>...
@@ -25,6 +26,13 @@ skip            skip the current patch"
 . git-sh-setup
 set_reflog_action am
 require_work_tree
+orig_pwd=$(pwd)
+cd_to_toplevel
+if test "$(pwd)" = "$orig_pwd"; then
+	orig_pwd=
+else
+	orig_pwd="$orig_pwd/"
+fi
 
 git var GIT_COMMITTER_IDENT >/dev/null || exit
 
@@ -121,6 +129,21 @@ reread_subject () {
 	git stripspace <"$1" | sed -e 1q
 }
 
+shellquote() {
+	printf \'
+	printf "$1" | sed "s/'/\\'/g"
+	echo \'
+}
+
+handle_file_args() {
+	for i in "$@"; do
+		case "$i" in
+		/*) shellquote "$i";;
+		 *) shellquote "$orig_pwd$i";;
+		esac
+	done
+}
+
 prec=4
 dotest=.dotest sign= utf8=t keep= skip= interactive= resolved= binary=
 resolvemsg= resume=
@@ -148,7 +171,7 @@ do
 	--skip)
 		skip=t ;;
 	-d|--dotest)
-		shift; dotest=$1;;
+		shift; eval dotest=`handle_file_args "$1"` ;;
 	--resolvemsg)
 		shift; resolvemsg=$1 ;;
 	--whitespace)
@@ -163,6 +186,8 @@ do
 	shift
 done
 
+eval set -- `handle_file_args "$@"`
+
 # If the dotest directory exists, but we have finished applying all the
 # patches in them, clear it out.
 if test -d "$dotest" &&

git-am.sh, t/t4150-am-subdir.sh

diff --git a/git-am.sh b/git-am.sh
index a2c6fea..de34636 100755
--- a/git-am.sh
+++ b/git-am.sh
@@ -24,6 +24,7 @@ r,resolved      to be used after a patch failure
 skip            skip the current patch"
 
 . git-sh-setup
+prefix=$(git rev-parse --show-prefix)
 set_reflog_action am
 require_work_tree
 cd_to_toplevel
@@ -206,6 +207,24 @@ else
 	# Start afresh.
 	mkdir -p "$dotest" || exit
 
+	if test -n "$prefix" && test $# != 0
+	then
+		first=t
+		for arg
+		do
+			test -n "$first" && {
+				set x
+				first=
+			}
+			case "$arg" in
+			/*)
+				set "$@" "$arg" ;;
+			*)
+				set "$@" "$prefix$arg" ;;
+			esac
+		done
+		shift
+	fi
 	git mailsplit -d"$prec" -o"$dotest" -b -- "$@" > "$dotest/last" ||  {
 		rm -fr "$dotest"
 		exit 1
diff --git a/t/t4150-am-subdir.sh b/t/t4150-am-subdir.sh
new file mode 100755
index 0000000..929d2cb
--- /dev/null
+++ b/t/t4150-am-subdir.sh
@@ -0,0 +1,72 @@
+#!/bin/sh
+
+test_description='git am running from a subdirectory'
+
+. ./test-lib.sh
+
+test_expect_success setup '
+	echo hello >world &&
+	git add world &&
+	test_tick &&
+	git commit -m initial &&
+	git tag initial &&
+	echo goodbye >world &&
+	git add world &&
+	test_tick &&
+	git commit -m second &&
+	git format-patch --stdout HEAD^ >patchfile &&
+	: >expect
+'
+
+test_expect_success 'am regularly from stdin' '
+	git checkout initial &&
+	git am <patchfile &&
+	git diff master >actual &&
+	diff -u expect actual
+'
+
+test_expect_success 'am regularly from file' '
+	git checkout initial &&
+	git am patchfile &&
+	git diff master >actual &&
+	diff -u expect actual
+'
+
+test_expect_success 'am regularly from stdin in subdirectory' '
+	rm -fr subdir &&
+	git checkout initial &&
+	(
+		mkdir -p subdir &&
+		cd subdir &&
+		git am <../patchfile
+	) &&
+	git diff master>actual &&
+	diff -u expect actual
+'
+
+test_expect_success 'am regularly from file in subdirectory' '
+	rm -fr subdir &&
+	git checkout initial &&
+	(
+		mkdir -p subdir &&
+		cd subdir &&
+		git am ../patchfile
+	) &&
+	git diff master >actual &&
+	diff -u expect actual
+'
+
+test_expect_success 'am regularly from file in subdirectory with full path' '
+	rm -fr subdir &&
+	git checkout initial &&
+	P=$(pwd) &&
+	(
+		mkdir -p subdir &&
+		cd subdir &&
+		git am "$P/patchfile"
+	) &&
+	git diff master >actual &&
+	diff -u expect actual
+'
+
+test_done