Gracefully handle bad characters in Turtle blank node syntax

3 files changed, 11 insertions, 2 deletions

diff --git a/src/attributes.h b/src/attributes.h
index 25eb91d0..502634b0 100644
--- a/src/attributes.h
+++ b/src/attributes.h
@@ -10,4 +10,10 @@
 #  define SERD_MALLOC_FUNC
 #endif
 
+#ifdef __GNUC__
+#  define SERD_NODISCARD __attribute__((warn_unused_result))
+#else
+#  define SERD_NODISCARD
+#endif
+
 #endif // SERD_ATTRIBUTES_H
diff --git a/src/n3.c b/src/n3.c
index bffc423b..09e6792b 100644
--- a/src/n3.c
+++ b/src/n3.c
@@ -997,7 +997,9 @@ read_BLANK_NODE_LABEL(SerdReader* const reader,
                       bool* const       ate_dot)
 {
   eat_byte_safe(reader, '_');
-  eat_byte_check(reader, ':');
+  if (!eat_byte_check(reader, ':')) {
+    return SERD_ERR_BAD_SYNTAX;
+  }
 
   const Ref ref = *dest =
     push_node(reader,
diff --git a/src/reader.h b/src/reader.h
index 689eeecb..cccaa8a9 100644
--- a/src/reader.h
+++ b/src/reader.h
@@ -4,6 +4,7 @@
 #ifndef SERD_READER_H
 #define SERD_READER_H
 
+#include "attributes.h"
 #include "byte_source.h"
 #include "stack.h"
 
@@ -131,7 +132,7 @@ eat_byte_safe(SerdReader* reader, const int byte)
   return c;
 }
 
-static inline int
+static inline int SERD_NODISCARD
 eat_byte_check(SerdReader* reader, const int byte)
 {
   const int c = peek_byte(reader);