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 <[email protected]>
Acked-by: Ævar Arnfjörð Bjarmason <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: Denton-L

t/t4203-mailmap.sh

@@ -634,7 +634,8 @@ test_expect_success 'Log output with --use-mailmap' '
 	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 @@ test_expect_success 'Log output with log.mailmap' '
 	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 @@ test_expect_success 'log.mailmap=false disables mailmap' '
 	Author: nick1 <[email protected]>
 	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 @@ test_expect_success '--no-use-mailmap disables mailmap' '
 	Author: nick1 <[email protected]>
 	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 @@ test_expect_success 'Grep author with --use-mailmap' '
 	Author: Santa Claus <[email protected]>
 	Author: Santa Claus <[email protected]>
 	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 @@ test_expect_success 'Grep author with log.mailmap' '
 	Author: Santa Claus <[email protected]>
 	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
 '