t4203: stop losing return codes of git commands

In a pipe, only the return code of the last command is used. Thus, all
other commands will have their return codes masked. Rewrite pipes so
that there are no git commands upstream so that their failure is
reported.

Signed-off-by: Denton Liu <liu.denton@gmail.com>
Acked-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t4203-mailmap.sh

diff --git a/t/t4203-mailmap.sh b/t/t4203-mailmap.sh
index 89cb300..c9cb1aa 100755
--- a/t/t4203-mailmap.sh
+++ b/t/t4203-mailmap.sh
@@ -634,7 +634,8 @@
 	Author: $GIT_AUTHOR_NAME <$GIT_AUTHOR_EMAIL>
 	EOF
 
-	git log --use-mailmap | grep Author >actual &&
+	git log --use-mailmap >log &&
+	grep Author log >actual &&
 	test_cmp expect actual
 '
 
@@ -651,7 +652,8 @@
 	Author: $GIT_AUTHOR_NAME <$GIT_AUTHOR_EMAIL>
 	EOF
 
-	git -c log.mailmap=True log | grep Author >actual &&
+	git -c log.mailmap=True log >log &&
+	grep Author log >actual &&
 	test_cmp expect actual
 '
 
@@ -665,7 +667,8 @@
 	Author: nick1 <bugs@company.xx>
 	Author: $GIT_AUTHOR_NAME <$GIT_AUTHOR_EMAIL>
 	EOF
-	git -c log.mailmap=false log | grep Author >actual &&
+	git -c log.mailmap=false log >log &&
+	grep Author log >actual &&
 	test_cmp expect actual
 '
 
@@ -679,7 +682,8 @@
 	Author: nick1 <bugs@company.xx>
 	Author: $GIT_AUTHOR_NAME <$GIT_AUTHOR_EMAIL>
 	EOF
-	git log --no-use-mailmap | grep Author > actual &&
+	git log --no-use-mailmap >log &&
+	grep Author log >actual &&
 	test_cmp expect actual
 '
 
@@ -690,7 +694,8 @@
 	Author: Santa Claus <santa.claus@northpole.xx>
 	Author: Santa Claus <santa.claus@northpole.xx>
 	EOF
-	git log --use-mailmap --author Santa | grep Author >actual &&
+	git log --use-mailmap --author Santa >log &&
+	grep Author log >actual &&
 	test_cmp expect actual
 '
 
@@ -702,13 +707,15 @@
 	Author: Santa Claus <santa.claus@northpole.xx>
 	EOF
 
-	git -c log.mailmap=True log --author Santa | grep Author >actual &&
+	git -c log.mailmap=True log --author Santa >log &&
+	grep Author log >actual &&
 	test_cmp expect actual
 '
 
 test_expect_success 'log.mailmap is true by default these days' '
 	test_config mailmap.file complex.map &&
-	git log --author Santa | grep Author >actual &&
+	git log --author Santa >log &&
+	grep Author log >actual &&
 	test_cmp expect actual
 '