From 9275161d0fbc9dbbca547b8de78441d934fbfb1b Mon Sep 17 00:00:00 2001
From: yuyi <yuyi98@163.com>
Date: Sun, 19 Mar 2023 15:52:45 +0800
Subject: [PATCH] strconv: fix v_sprintf with '%%' (#17708)

---
 vlib/strconv/format_test.v | 6 ++++++
 vlib/strconv/vprintf.c.v   | 6 ++++++
 2 files changed, 12 insertions(+)

diff --git a/vlib/strconv/format_test.v b/vlib/strconv/format_test.v
index 150a6d8973..16af688b53 100644
--- a/vlib/strconv/format_test.v
+++ b/vlib/strconv/format_test.v
@@ -113,3 +113,9 @@ fn test_sprintf_does_not_double_free_on_g() {
 	x := 3.141516
 	assert strconv.v_sprintf('aaa %G', x) == 'aaa 3.141516'
 }
+
+fn test_sprintf_with_escape() {
+	n := 69
+	s := strconv.v_sprintf('%d is 100%% awesome', n)
+	assert s == '69 is 100% awesome'
+}
diff --git a/vlib/strconv/vprintf.c.v b/vlib/strconv/vprintf.c.v
index 382d44db98..475da651c6 100644
--- a/vlib/strconv/vprintf.c.v
+++ b/vlib/strconv/vprintf.c.v
@@ -75,6 +75,12 @@ pub fn v_sprintf(str string, pt ...voidptr) string {
 			i++
 			continue
 		}
+		if ch == `%` && status == .field_char {
+			status = .norm_char
+			res.write_u8(ch)
+			i++
+			continue
+		}
 		if ch == `%` && status == .norm_char {
 			status = .field_char
 			i++