[PATCH v5 1/2] add-patch: do not show UI messages on stderr

["Rubén Justo" <rjusto@gmail.com>]

There is no need to show some UI messages on stderr, and yet doing so
may produce some undesirable results, such as messages appearing in an
unexpected order.

Let's use stdout for all UI messages, and adjusts the tests accordingly.

Signed-off-by: Rubén Justo <rjusto@gmail.com>
---
 add-patch.c                | 13 ++++++-------
 t/t3701-add-interactive.sh | 12 ++++++------
 2 files changed, 12 insertions(+), 13 deletions(-)

diff --git a/add-patch.c b/add-patch.c
index 0997d4af73..fc0eed4fd4 100644
--- a/add-patch.c
+++ b/add-patch.c
@@ -293,10 +293,9 @@ static void err(struct add_p_state *s, const char *fmt, ...)
 	va_list args;
 
 	va_start(args, fmt);
-	fputs(s->s.error_color, stderr);
-	vfprintf(stderr, fmt, args);
-	fputs(s->s.reset_color, stderr);
-	fputc('\n', stderr);
+	fputs(s->s.error_color, stdout);
+	vprintf(fmt, args);
+	puts(s->s.reset_color);
 	va_end(args);
 }
 
@@ -1326,7 +1325,7 @@ static int apply_for_checkout(struct add_p_state *s, struct strbuf *diff,
 		err(s, _("Nothing was applied.\n"));
 	} else
 		/* As a last resort, show the diff to the user */
-		fwrite(diff->buf, diff->len, 1, stderr);
+		fwrite(diff->buf, diff->len, 1, stdout);
 
 	return 0;
 }
@@ -1778,9 +1777,9 @@ int run_add_p(struct repository *r, enum add_p_mode mode,
 			break;
 
 	if (s.file_diff_nr == 0)
-		fprintf(stderr, _("No changes.\n"));
+		err(&s, _("No changes."));
 	else if (binary_count == s.file_diff_nr)
-		fprintf(stderr, _("Only binary files changed.\n"));
+		err(&s, _("Only binary files changed."));
 
 	add_p_state_clear(&s);
 	return 0;
diff --git a/t/t3701-add-interactive.sh b/t/t3701-add-interactive.sh
index 04d8333373..c5531520cb 100755
--- a/t/t3701-add-interactive.sh
+++ b/t/t3701-add-interactive.sh
@@ -45,13 +45,13 @@ test_expect_success 'warn about add.interactive.useBuiltin' '
 	cat >expect <<-\EOF &&
 	warning: the add.interactive.useBuiltin setting has been removed!
 	See its entry in '\''git help config'\'' for details.
-	No changes.
 	EOF
+	echo "No changes." >expect.out &&
 
 	for v in = =true =false
 	do
 		git -c "add.interactive.useBuiltin$v" add -p >out 2>actual &&
-		test_must_be_empty out &&
+		test_cmp expect.out out &&
 		test_cmp expect actual || return 1
 	done
 '
@@ -335,13 +335,13 @@ test_expect_success 'different prompts for mode change/deleted' '
 
 test_expect_success 'correct message when there is nothing to do' '
 	git reset --hard &&
-	git add -p 2>err &&
-	test_grep "No changes" err &&
+	git add -p >out &&
+	test_grep "No changes" out &&
 	printf "\\0123" >binary &&
 	git add binary &&
 	printf "\\0abc" >binary &&
-	git add -p 2>err &&
-	test_grep "Only binary files changed" err
+	git add -p >out &&
+	test_grep "Only binary files changed" out
 '
 
 test_expect_success 'setup again' '
-- 
2.45.0.2.g84ce137e4a