lib: gracefully handle truncated format strings in uc_printf_common()

Signed-off-by: Jo-Philipp Wich <jo@mein.io>

1 files changed, 14 insertions, 0 deletions

diff --git a/tests/custom/03_bugs/19_truncated_format_string b/tests/custom/03_bugs/19_truncated_format_string
new file mode 100644
index 0000000..8ddd0a3
--- /dev/null
+++ b/tests/custom/03_bugs/19_truncated_format_string
@@ -0,0 +1,14 @@
+When processing a truncated format string, uc_printf_common() - which is
+used by `sprintf()` and `printf()` in ucode - appended trailing garbage
+to the resulting string.
+
+-- Expect stdout --
+[ 37, null ]
+-- End --
+
+-- Testcase --
+{%
+	let s = sprintf("%");
+	print(ord(s, 0, 1), "\n");
+%}
+-- End --