lexer: fix infinite loop in lineinfo encoding when consuming large chunks

A logic flaw in the lineinfo encoding function led to an infinite tight
loop when a buffer chunk with 128 byte or more got consumed, which may
happen when parsing very long literals.

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

1 files changed, 13 insertions, 0 deletions

diff --git a/tests/03_bugs/07_lexer_overlong_lines b/tests/03_bugs/07_lexer_overlong_lines
new file mode 100644
index 0000000..d2dd3be
--- /dev/null
+++ b/tests/03_bugs/07_lexer_overlong_lines
@@ -0,0 +1,13 @@
+A logic flaw in the lineinfo encoding function led to an endless tight
+loop when a buffer chunk with 128 byte got consumed, which may happen
+when parsing very long literals.
+
+-- Testcase --
+{%
+	print("abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefg\n");
+%}
+-- End --
+
+-- Expect stdout --
+abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefg
+-- End --