lexer: fix infinite loop on parsing unterminated expression blocks

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

2 files changed, 18 insertions, 0 deletions

diff --git a/lexer.c b/lexer.c
index 6e1dcd9..616f484 100644
--- a/lexer.c
+++ b/lexer.c
@@ -1107,6 +1107,8 @@ lex_step(uc_lexer *lex, FILE *fp)
 		}
 
 		/* premature EOF */
+		lex->state = UT_LEX_EOF;
+
 		return emit_op(lex, lex->source->off, TK_ERROR, ucv_string_new("Unterminated template block"));
 
 
diff --git a/tests/custom/03_bugs/17_hang_on_unclosed_expression_block b/tests/custom/03_bugs/17_hang_on_unclosed_expression_block
new file mode 100644
index 0000000..25128bb
--- /dev/null
+++ b/tests/custom/03_bugs/17_hang_on_unclosed_expression_block
@@ -0,0 +1,16 @@
+When parsing an unclosed expression block, the lexer did end up in an
+infinite loop.
+
+-- Expect stderr --
+Syntax error: Unterminated template block
+In line 1, byte 6:
+
+ `{{ 1`
+      ^-- Near here
+
+
+-- End --
+
+-- Testcase --
+{{ 1
+-- End --