Merge branch 'js/mergetool-optim'

"git mergetool" and its tests now spawn fewer subprocesses.

* js/mergetool-optim:
  mergetool: use shell variable magic instead of `awk`
  mergetool: dissect strings with shell variable magic instead of `expr`
  t7610-mergetool: use test_cmp instead of test $(cat file) = $txt
  t7610-mergetool: do not place pipelines headed by `yes` in subshells

2 files changed, 208 insertions, 146 deletions

diff --git a/git-mergetool.sh b/git-mergetool.sh
index 88fa6a914a..e3f6d543fb 100755
--- a/git-mergetool.sh
+++ b/git-mergetool.sh
@@ -228,9 +228,8 @@ stage_submodule () {
 }
 
 checkout_staged_file () {
-	tmpfile=$(expr \
-		"$(git checkout-index --temp --stage="$1" "$2" 2>/dev/null)" \
-		: '\([^	]*\)	')
+	tmpfile="$(git checkout-index --temp --stage="$1" "$2" 2>/dev/null)" &&
+	tmpfile=${tmpfile%%'	'*}
 
 	if test $? -eq 0 && test -n "$tmpfile"
 	then
@@ -255,13 +254,16 @@ merge_file () {
 		return 1
 	fi
 
-	if BASE=$(expr "$MERGED" : '\(.*\)\.[^/]*$')
-	then
-		ext=$(expr "$MERGED" : '.*\(\.[^/]*\)$')
-	else
+	# extract file extension from the last path component
+	case "${MERGED##*/}" in
+	*.*)
+		ext=.${MERGED##*.}
+		BASE=${MERGED%"$ext"}
+		;;
+	*)
 		BASE=$MERGED
 		ext=
-	fi
+	esac
 
 	mergetool_tmpdir_init
 
@@ -277,15 +279,30 @@ merge_file () {
 	REMOTE="$MERGETOOL_TMPDIR/${BASE}_REMOTE_$$$ext"
 	BASE="$MERGETOOL_TMPDIR/${BASE}_BASE_$$$ext"
 
-	base_mode=$(git ls-files -u -- "$MERGED" | awk '{if ($3==1) print $1;}')
-	local_mode=$(git ls-files -u -- "$MERGED" | awk '{if ($3==2) print $1;}')
-	remote_mode=$(git ls-files -u -- "$MERGED" | awk '{if ($3==3) print $1;}')
+	base_mode= local_mode= remote_mode=
+
+	# here, $IFS is just a LF
+	for line in $f
+	do
+		mode=${line%% *}		# 1st word
+		sha1=${line#"$mode "}
+		sha1=${sha1%% *}		# 2nd word
+		case "${line#$mode $sha1 }" in	# remainder
+		'1	'*)
+			base_mode=$mode
+			;;
+		'2	'*)
+			local_mode=$mode local_sha1=$sha1
+			;;
+		'3	'*)
+			remote_mode=$mode remote_sha1=$sha1
+			;;
+		esac
+	done
 
 	if is_submodule "$local_mode" || is_submodule "$remote_mode"
 	then
 		echo "Submodule merge conflict for '$MERGED':"
-		local_sha1=$(git ls-files -u -- "$MERGED" | awk '{if ($3==2) print $2;}')
-		remote_sha1=$(git ls-files -u -- "$MERGED" | awk '{if ($3==3) print $2;}')
 		describe_file "$local_mode" "local" "$local_sha1"
 		describe_file "$remote_mode" "remote" "$remote_sha1"
 		resolve_submodule_merge
@@ -406,7 +423,7 @@ main () {
 		-t|--tool*)
 			case "$#,$1" in
 			*,*=*)
-				merge_tool=$(expr "z$1" : 'z-[^=]*=\(.*\)')
+				merge_tool=${1#*=}
 				;;
 			1,*)
 				usage ;;
diff --git a/t/t7610-mergetool.sh b/t/t7610-mergetool.sh
index 5b61c10a9c..ad288ddc69 100755
--- a/t/t7610-mergetool.sh
+++ b/t/t7610-mergetool.sh
@@ -131,17 +131,21 @@ test_expect_success 'custom mergetool' '
 	git checkout -b test$test_count branch1 &&
 	git submodule update -N &&
 	test_must_fail git merge master &&
-	( yes "" | git mergetool both ) &&
-	( yes "" | git mergetool file1 file1 ) &&
-	( yes "" | git mergetool file2 "spaced name" ) &&
-	( yes "" | git mergetool subdir/file3 ) &&
-	( yes "d" | git mergetool file11 ) &&
-	( yes "d" | git mergetool file12 ) &&
-	( yes "l" | git mergetool submod ) &&
-	test "$(cat file1)" = "master updated" &&
-	test "$(cat file2)" = "master new" &&
-	test "$(cat subdir/file3)" = "master new sub" &&
-	test "$(cat submod/bar)" = "branch1 submodule" &&
+	yes "" | git mergetool both &&
+	yes "" | git mergetool file1 file1 &&
+	yes "" | git mergetool file2 "spaced name" &&
+	yes "" | git mergetool subdir/file3 &&
+	yes "d" | git mergetool file11 &&
+	yes "d" | git mergetool file12 &&
+	yes "l" | git mergetool submod &&
+	echo "master updated" >expect &&
+	test_cmp expect file1 &&
+	echo "master new" >expect &&
+	test_cmp expect file2 &&
+	echo "master new sub" >expect &&
+	test_cmp expect subdir/file3 &&
+	echo "branch1 submodule" >expect &&
+	test_cmp expect submod/bar &&
 	git commit -m "branch1 resolved with mergetool"
 '
 
@@ -153,17 +157,21 @@ test_expect_success 'gui mergetool' '
 	git checkout -b test$test_count branch1 &&
 	git submodule update -N &&
 	test_must_fail git merge master &&
-	( yes "" | git mergetool --gui both ) &&
-	( yes "" | git mergetool -g file1 file1 ) &&
-	( yes "" | git mergetool --gui file2 "spaced name" ) &&
-	( yes "" | git mergetool --gui subdir/file3 ) &&
-	( yes "d" | git mergetool --gui file11 ) &&
-	( yes "d" | git mergetool --gui file12 ) &&
-	( yes "l" | git mergetool --gui submod ) &&
-	test "$(cat file1)" = "gui master updated" &&
-	test "$(cat file2)" = "gui master new" &&
-	test "$(cat subdir/file3)" = "gui master new sub" &&
-	test "$(cat submod/bar)" = "branch1 submodule" &&
+	yes "" | git mergetool --gui both &&
+	yes "" | git mergetool -g file1 file1 &&
+	yes "" | git mergetool --gui file2 "spaced name" &&
+	yes "" | git mergetool --gui subdir/file3 &&
+	yes "d" | git mergetool --gui file11 &&
+	yes "d" | git mergetool --gui file12 &&
+	yes "l" | git mergetool --gui submod &&
+	echo "gui master updated" >expect &&
+	test_cmp expect file1 &&
+	echo "gui master new" >expect &&
+	test_cmp expect file2 &&
+	echo "gui master new sub" >expect &&
+	test_cmp expect subdir/file3 &&
+	echo "branch1 submodule" >expect &&
+	test_cmp expect submod/bar &&
 	git commit -m "branch1 resolved with mergetool"
 '
 
@@ -172,17 +180,21 @@ test_expect_success 'gui mergetool without merge.guitool set falls back to merge
 	git checkout -b test$test_count branch1 &&
 	git submodule update -N &&
 	test_must_fail git merge master &&
-	( yes "" | git mergetool --gui both ) &&
-	( yes "" | git mergetool -g file1 file1 ) &&
-	( yes "" | git mergetool --gui file2 "spaced name" ) &&
-	( yes "" | git mergetool --gui subdir/file3 ) &&
-	( yes "d" | git mergetool --gui file11 ) &&
-	( yes "d" | git mergetool --gui file12 ) &&
-	( yes "l" | git mergetool --gui submod ) &&
-	test "$(cat file1)" = "master updated" &&
-	test "$(cat file2)" = "master new" &&
-	test "$(cat subdir/file3)" = "master new sub" &&
-	test "$(cat submod/bar)" = "branch1 submodule" &&
+	yes "" | git mergetool --gui both &&
+	yes "" | git mergetool -g file1 file1 &&
+	yes "" | git mergetool --gui file2 "spaced name" &&
+	yes "" | git mergetool --gui subdir/file3 &&
+	yes "d" | git mergetool --gui file11 &&
+	yes "d" | git mergetool --gui file12 &&
+	yes "l" | git mergetool --gui submod &&
+	echo "master updated" >expect &&
+	test_cmp expect file1 &&
+	echo "master new" >expect &&
+	test_cmp expect file2 &&
+	echo "master new sub" >expect &&
+	test_cmp expect subdir/file3 &&
+	echo "branch1 submodule" >expect &&
+	test_cmp expect submod/bar &&
 	git commit -m "branch1 resolved with mergetool"
 '
 
@@ -195,19 +207,20 @@ test_expect_success 'mergetool crlf' '
 	test_config core.autocrlf true &&
 	git checkout -b test$test_count branch1 &&
 	test_must_fail git merge master &&
-	( yes "" | git mergetool file1 ) &&
-	( yes "" | git mergetool file2 ) &&
-	( yes "" | git mergetool "spaced name" ) &&
-	( yes "" | git mergetool both ) &&
-	( yes "" | git mergetool subdir/file3 ) &&
-	( yes "d" | git mergetool file11 ) &&
-	( yes "d" | git mergetool file12 ) &&
-	( yes "r" | git mergetool submod ) &&
+	yes "" | git mergetool file1 &&
+	yes "" | git mergetool file2 &&
+	yes "" | git mergetool "spaced name" &&
+	yes "" | git mergetool both &&
+	yes "" | git mergetool subdir/file3 &&
+	yes "d" | git mergetool file11 &&
+	yes "d" | git mergetool file12 &&
+	yes "r" | git mergetool submod &&
 	test "$(printf x | cat file1 -)" = "$(printf "master updated\r\nx")" &&
 	test "$(printf x | cat file2 -)" = "$(printf "master new\r\nx")" &&
 	test "$(printf x | cat subdir/file3 -)" = "$(printf "master new sub\r\nx")" &&
 	git submodule update -N &&
-	test "$(cat submod/bar)" = "master submodule" &&
+	echo "master submodule" >expect &&
+	test_cmp expect submod/bar &&
 	git commit -m "branch1 resolved with mergetool - autocrlf"
 '
 
@@ -218,8 +231,9 @@ test_expect_success 'mergetool in subdir' '
 	(
 		cd subdir &&
 		test_must_fail git merge master &&
-		( yes "" | git mergetool file3 ) &&
-		test "$(cat file3)" = "master new sub"
+		yes "" | git mergetool file3 &&
+		echo "master new sub" >expect &&
+		test_cmp expect file3
 	)
 '
 
@@ -230,16 +244,19 @@ test_expect_success 'mergetool on file in parent dir' '
 	(
 		cd subdir &&
 		test_must_fail git merge master &&
-		( yes "" | git mergetool file3 ) &&
-		( yes "" | git mergetool ../file1 ) &&
-		( yes "" | git mergetool ../file2 ../spaced\ name ) &&
-		( yes "" | git mergetool ../both ) &&
-		( yes "d" | git mergetool ../file11 ) &&
-		( yes "d" | git mergetool ../file12 ) &&
-		( yes "l" | git mergetool ../submod ) &&
-		test "$(cat ../file1)" = "master updated" &&
-		test "$(cat ../file2)" = "master new" &&
-		test "$(cat ../submod/bar)" = "branch1 submodule" &&
+		yes "" | git mergetool file3 &&
+		yes "" | git mergetool ../file1 &&
+		yes "" | git mergetool ../file2 ../spaced\ name &&
+		yes "" | git mergetool ../both &&
+		yes "d" | git mergetool ../file11 &&
+		yes "d" | git mergetool ../file12 &&
+		yes "l" | git mergetool ../submod &&
+		echo "master updated" >expect &&
+		test_cmp expect ../file1 &&
+		echo "master new" >expect &&
+		test_cmp expect ../file2 &&
+		echo "branch1 submodule" >expect &&
+		test_cmp expect ../submod/bar &&
 		git commit -m "branch1 resolved with mergetool - subdir"
 	)
 '
@@ -250,9 +267,9 @@ test_expect_success 'mergetool skips autoresolved' '
 	git submodule update -N &&
 	test_must_fail git merge master &&
 	test -n "$(git ls-files -u)" &&
-	( yes "d" | git mergetool file11 ) &&
-	( yes "d" | git mergetool file12 ) &&
-	( yes "l" | git mergetool submod ) &&
+	yes "d" | git mergetool file11 &&
+	yes "d" | git mergetool file12 &&
+	yes "l" | git mergetool submod &&
 	output="$(git mergetool --no-prompt)" &&
 	test "$output" = "No files need merging"
 '
@@ -264,13 +281,17 @@ test_expect_success 'mergetool merges all from subdir (rerere disabled)' '
 	(
 		cd subdir &&
 		test_must_fail git merge master &&
-		( yes "r" | git mergetool ../submod ) &&
-		( yes "d" "d" | git mergetool --no-prompt ) &&
-		test "$(cat ../file1)" = "master updated" &&
-		test "$(cat ../file2)" = "master new" &&
-		test "$(cat file3)" = "master new sub" &&
+		yes "r" | git mergetool ../submod &&
+		yes "d" "d" | git mergetool --no-prompt &&
+		echo "master updated" >expect &&
+		test_cmp expect ../file1 &&
+		echo "master new" >expect &&
+		test_cmp expect ../file2 &&
+		echo "master new sub" >expect &&
+		test_cmp expect file3 &&
 		( cd .. && git submodule update -N ) &&
-		test "$(cat ../submod/bar)" = "master submodule" &&
+		echo "master submodule" >expect &&
+		test_cmp expect ../submod/bar &&
 		git commit -m "branch2 resolved by mergetool from subdir"
 	)
 '
@@ -283,13 +304,17 @@ test_expect_success 'mergetool merges all from subdir (rerere enabled)' '
 	(
 		cd subdir &&
 		test_must_fail git merge master &&
-		( yes "r" | git mergetool ../submod ) &&
-		( yes "d" "d" | git mergetool --no-prompt ) &&
-		test "$(cat ../file1)" = "master updated" &&
-		test "$(cat ../file2)" = "master new" &&
-		test "$(cat file3)" = "master new sub" &&
+		yes "r" | git mergetool ../submod &&
+		yes "d" "d" | git mergetool --no-prompt &&
+		echo "master updated" >expect &&
+		test_cmp expect ../file1 &&
+		echo "master new" >expect &&
+		test_cmp expect ../file2 &&
+		echo "master new sub" >expect &&
+		test_cmp expect file3 &&
 		( cd .. && git submodule update -N ) &&
-		test "$(cat ../submod/bar)" = "master submodule" &&
+		echo "master submodule" >expect &&
+		test_cmp expect ../submod/bar &&
 		git commit -m "branch2 resolved by mergetool from subdir"
 	)
 '
@@ -301,8 +326,8 @@ test_expect_success 'mergetool skips resolved paths when rerere is active' '
 	git checkout -b test$test_count branch1 &&
 	git submodule update -N &&
 	test_must_fail git merge master &&
-	( yes "l" | git mergetool --no-prompt submod ) &&
-	( yes "d" "d" | git mergetool --no-prompt ) &&
+	yes "l" | git mergetool --no-prompt submod &&
+	yes "d" "d" | git mergetool --no-prompt &&
 	git submodule update -N &&
 	output="$(yes "n" | git mergetool --no-prompt)" &&
 	test "$output" = "No files need merging"
@@ -343,9 +368,10 @@ test_expect_success 'mergetool takes partial path' '
 	git submodule update -N &&
 	test_must_fail git merge master &&
 
-	( yes "" | git mergetool subdir ) &&
+	yes "" | git mergetool subdir &&
 
-	test "$(cat subdir/file3)" = "master new sub"
+	echo "master new sub" >expect &&
+	test_cmp expect subdir/file3
 '
 
 test_expect_success 'mergetool delete/delete conflict' '
@@ -410,14 +436,16 @@ test_expect_success 'deleted vs modified submodule' '
 	git checkout -b test$test_count.a test$test_count &&
 	test_must_fail git merge master &&
 	test -n "$(git ls-files -u)" &&
-	( yes "" | git mergetool file1 file2 spaced\ name subdir/file3 ) &&
-	( yes "" | git mergetool both ) &&
-	( yes "d" | git mergetool file11 file12 ) &&
-	( yes "r" | git mergetool submod ) &&
+	yes "" | git mergetool file1 file2 spaced\ name subdir/file3 &&
+	yes "" | git mergetool both &&
+	yes "d" | git mergetool file11 file12 &&
+	yes "r" | git mergetool submod &&
 	rmdir submod && mv submod-movedaside submod &&
-	test "$(cat submod/bar)" = "branch1 submodule" &&
+	echo "branch1 submodule" >expect &&
+	test_cmp expect submod/bar &&
 	git submodule update -N &&
-	test "$(cat submod/bar)" = "master submodule" &&
+	echo "master submodule" >expect &&
+	test_cmp expect submod/bar &&
 	output="$(git mergetool --no-prompt)" &&
 	test "$output" = "No files need merging" &&
 	git commit -m "Merge resolved by keeping module" &&
@@ -427,10 +455,10 @@ test_expect_success 'deleted vs modified submodule' '
 	git submodule update -N &&
 	test_must_fail git merge master &&
 	test -n "$(git ls-files -u)" &&
-	( yes "" | git mergetool file1 file2 spaced\ name subdir/file3 ) &&
-	( yes "" | git mergetool both ) &&
-	( yes "d" | git mergetool file11 file12 ) &&
-	( yes "l" | git mergetool submod ) &&
+	yes "" | git mergetool file1 file2 spaced\ name subdir/file3 &&
+	yes "" | git mergetool both &&
+	yes "d" | git mergetool file11 file12 &&
+	yes "l" | git mergetool submod &&
 	test ! -e submod &&
 	output="$(git mergetool --no-prompt)" &&
 	test "$output" = "No files need merging" &&
@@ -441,10 +469,10 @@ test_expect_success 'deleted vs modified submodule' '
 	git submodule update -N &&
 	test_must_fail git merge test$test_count &&
 	test -n "$(git ls-files -u)" &&
-	( yes "" | git mergetool file1 file2 spaced\ name subdir/file3 ) &&
-	( yes "" | git mergetool both ) &&
-	( yes "d" | git mergetool file11 file12 ) &&
-	( yes "r" | git mergetool submod ) &&
+	yes "" | git mergetool file1 file2 spaced\ name subdir/file3 &&
+	yes "" | git mergetool both &&
+	yes "d" | git mergetool file11 file12 &&
+	yes "r" | git mergetool submod &&
 	test ! -e submod &&
 	test -d submod.orig &&
 	git submodule update -N &&
@@ -457,13 +485,15 @@ test_expect_success 'deleted vs modified submodule' '
 	git submodule update -N &&
 	test_must_fail git merge test$test_count &&
 	test -n "$(git ls-files -u)" &&
-	( yes "" | git mergetool file1 file2 spaced\ name subdir/file3 ) &&
-	( yes "" | git mergetool both ) &&
-	( yes "d" | git mergetool file11 file12 ) &&
-	( yes "l" | git mergetool submod ) &&
-	test "$(cat submod/bar)" = "master submodule" &&
-	git submodule update -N &&
-	test "$(cat submod/bar)" = "master submodule" &&
+	yes "" | git mergetool file1 file2 spaced\ name subdir/file3 &&
+	yes "" | git mergetool both &&
+	yes "d" | git mergetool file11 file12 &&
+	yes "l" | git mergetool submod &&
+	echo "master submodule" >expect &&
+	test_cmp expect submod/bar &&
+	git submodule update -N &&
+	echo "master submodule" >expect &&
+	test_cmp expect submod/bar &&
 	output="$(git mergetool --no-prompt)" &&
 	test "$output" = "No files need merging" &&
 	git commit -m "Merge resolved by keeping module"
@@ -481,14 +511,16 @@ test_expect_success 'file vs modified submodule' '
 	git checkout -b test$test_count.a branch1 &&
 	test_must_fail git merge master &&
 	test -n "$(git ls-files -u)" &&
-	( yes "" | git mergetool file1 file2 spaced\ name subdir/file3 ) &&
-	( yes "" | git mergetool both ) &&
-	( yes "d" | git mergetool file11 file12 ) &&
-	( yes "r" | git mergetool submod ) &&
+	yes "" | git mergetool file1 file2 spaced\ name subdir/file3 &&
+	yes "" | git mergetool both &&
+	yes "d" | git mergetool file11 file12 &&
+	yes "r" | git mergetool submod &&
 	rmdir submod && mv submod-movedaside submod &&
-	test "$(cat submod/bar)" = "branch1 submodule" &&
+	echo "branch1 submodule" >expect &&
+	test_cmp expect submod/bar &&
 	git submodule update -N &&
-	test "$(cat submod/bar)" = "master submodule" &&
+	echo "master submodule" >expect &&
+	test_cmp expect submod/bar &&
 	output="$(git mergetool --no-prompt)" &&
 	test "$output" = "No files need merging" &&
 	git commit -m "Merge resolved by keeping module" &&
@@ -497,12 +529,13 @@ test_expect_success 'file vs modified submodule' '
 	git checkout -b test$test_count.b test$test_count &&
 	test_must_fail git merge master &&
 	test -n "$(git ls-files -u)" &&
-	( yes "" | git mergetool file1 file2 spaced\ name subdir/file3 ) &&
-	( yes "" | git mergetool both ) &&
-	( yes "d" | git mergetool file11 file12 ) &&
-	( yes "l" | git mergetool submod ) &&
+	yes "" | git mergetool file1 file2 spaced\ name subdir/file3 &&
+	yes "" | git mergetool both &&
+	yes "d" | git mergetool file11 file12 &&
+	yes "l" | git mergetool submod &&
 	git submodule update -N &&
-	test "$(cat submod)" = "not a submodule" &&
+	echo "not a submodule" >expect &&
+	test_cmp expect submod &&
 	output="$(git mergetool --no-prompt)" &&
 	test "$output" = "No files need merging" &&
 	git commit -m "Merge resolved by keeping file" &&
@@ -513,13 +546,14 @@ test_expect_success 'file vs modified submodule' '
 	git submodule update -N &&
 	test_must_fail git merge test$test_count &&
 	test -n "$(git ls-files -u)" &&
-	( yes "" | git mergetool file1 file2 spaced\ name subdir/file3 ) &&
-	( yes "" | git mergetool both ) &&
-	( yes "d" | git mergetool file11 file12 ) &&
-	( yes "r" | git mergetool submod ) &&
+	yes "" | git mergetool file1 file2 spaced\ name subdir/file3 &&
+	yes "" | git mergetool both &&
+	yes "d" | git mergetool file11 file12 &&
+	yes "r" | git mergetool submod &&
 	test -d submod.orig &&
 	git submodule update -N &&
-	test "$(cat submod)" = "not a submodule" &&
+	echo "not a submodule" >expect &&
+	test_cmp expect submod &&
 	output="$(git mergetool --no-prompt)" &&
 	test "$output" = "No files need merging" &&
 	git commit -m "Merge resolved by keeping file" &&
@@ -529,13 +563,15 @@ test_expect_success 'file vs modified submodule' '
 	git submodule update -N &&
 	test_must_fail git merge test$test_count &&
 	test -n "$(git ls-files -u)" &&
-	( yes "" | git mergetool file1 file2 spaced\ name subdir/file3 ) &&
-	( yes "" | git mergetool both ) &&
-	( yes "d" | git mergetool file11 file12 ) &&
-	( yes "l" | git mergetool submod ) &&
-	test "$(cat submod/bar)" = "master submodule" &&
-	git submodule update -N &&
-	test "$(cat submod/bar)" = "master submodule" &&
+	yes "" | git mergetool file1 file2 spaced\ name subdir/file3 &&
+	yes "" | git mergetool both &&
+	yes "d" | git mergetool file11 file12 &&
+	yes "l" | git mergetool submod &&
+	echo "master submodule" >expect &&
+	test_cmp expect submod/bar &&
+	git submodule update -N &&
+	echo "master submodule" >expect &&
+	test_cmp expect submod/bar &&
 	output="$(git mergetool --no-prompt)" &&
 	test "$output" = "No files need merging" &&
 	git commit -m "Merge resolved by keeping module"
@@ -587,19 +623,23 @@ test_expect_success 'submodule in subdirectory' '
 	test_must_fail git merge test$test_count.a &&
 	(
 		cd subdir &&
-		( yes "l" | git mergetool subdir_module )
+		yes "l" | git mergetool subdir_module
 	) &&
-	test "$(cat subdir/subdir_module/file15)" = "test$test_count.b" &&
+	echo "test$test_count.b" >expect &&
+	test_cmp expect subdir/subdir_module/file15 &&
 	git submodule update -N &&
-	test "$(cat subdir/subdir_module/file15)" = "test$test_count.b" &&
+	echo "test$test_count.b" >expect &&
+	test_cmp expect subdir/subdir_module/file15 &&
 	git reset --hard &&
 	git submodule update -N &&
 
 	test_must_fail git merge test$test_count.a &&
-	( yes "r" | git mergetool subdir/subdir_module ) &&
-	test "$(cat subdir/subdir_module/file15)" = "test$test_count.b" &&
+	yes "r" | git mergetool subdir/subdir_module &&
+	echo "test$test_count.b" >expect &&
+	test_cmp expect subdir/subdir_module/file15 &&
 	git submodule update -N &&
-	test "$(cat subdir/subdir_module/file15)" = "test$test_count.a" &&
+	echo "test$test_count.a" >expect &&
+	test_cmp expect subdir/subdir_module/file15 &&
 	git commit -m "branch1 resolved with mergetool"
 '
 
@@ -615,22 +655,25 @@ test_expect_success 'directory vs modified submodule' '
 
 	test_must_fail git merge master &&
 	test -n "$(git ls-files -u)" &&
-	( yes "l" | git mergetool submod ) &&
-	test "$(cat submod/file16)" = "not a submodule" &&
+	yes "l" | git mergetool submod &&
+	echo "not a submodule" >expect &&
+	test_cmp expect submod/file16 &&
 	rm -rf submod.orig &&
 
 	git reset --hard &&
 	test_must_fail git merge master &&
 	test -n "$(git ls-files -u)" &&
 	test ! -e submod.orig &&
-	( yes "r" | git mergetool submod ) &&
+	yes "r" | git mergetool submod &&
 	test -d submod.orig &&
-	test "$(cat submod.orig/file16)" = "not a submodule" &&
+	echo "not a submodule" >expect &&
+	test_cmp expect submod.orig/file16 &&
 	rm -r submod.orig &&
 	mv submod-movedaside/.git submod &&
 	( cd submod && git clean -f && git reset --hard ) &&
 	git submodule update -N &&
-	test "$(cat submod/bar)" = "master submodule" &&
+	echo "master submodule" >expect &&
+	test_cmp expect submod/bar &&
 	git reset --hard &&
 	rm -rf submod-movedaside &&
 
@@ -638,17 +681,19 @@ test_expect_success 'directory vs modified submodule' '
 	git submodule update -N &&
 	test_must_fail git merge test$test_count &&
 	test -n "$(git ls-files -u)" &&
-	( yes "l" | git mergetool submod ) &&
+	yes "l" | git mergetool submod &&
 	git submodule update -N &&
-	test "$(cat submod/bar)" = "master submodule" &&
+	echo "master submodule" >expect &&
+	test_cmp expect submod/bar &&
 
 	git reset --hard &&
 	git submodule update -N &&
 	test_must_fail git merge test$test_count &&
 	test -n "$(git ls-files -u)" &&
 	test ! -e submod.orig &&
-	( yes "r" | git mergetool submod ) &&
-	test "$(cat submod/file16)" = "not a submodule" &&
+	yes "r" | git mergetool submod &&
+	echo "not a submodule" >expect &&
+	test_cmp expect submod/file16 &&
 
 	git reset --hard master &&
 	( cd submod && git clean -f && git reset --hard ) &&