fix reading version bytes on version mismatch error (fix #29)

rhysd · Jun 12, 2020 · 655e0c0 · 655e0c0
1 parent 6b0f242
commit 655e0c0
Showing 1 changed file with 13 additions and 3 deletions.
diff --git a/wain-syntax-binary/src/parser.rs b/wain-syntax-binary/src/parser.rs
@@ -246,9 +246,8 @@ impl<'s> Parse<'s> for Module<'s> {
         match parser.input {
             [0x01, 0x00, 0x00, 0x00, ..] => parser.eat(4),
             _ => {
-                return Err(
-                    parser.error(ErrorKind::VersionMismatch(parser.input.try_into().unwrap()))
-                )
+                let bytes = parser.input[..4].try_into().unwrap();
+                return Err(parser.error(ErrorKind::VersionMismatch(bytes)));
             }
         }
 
@@ -1153,4 +1152,15 @@ mod tests {
         let mut parser = Parser::new(&bin);
         let _: Root<'_, _> = unwrap(parser.parse());
     }
+
+    #[test]
+    fn regression_issue_29() {
+        // .asm.19.asm.195.
+        let bin: &[_] = b"\x00\x61\x73\x6d\x01\x31\x39\x00\x61\x73\x6d\x01\x31\x39\x35\x01";
+        let mut parser = Parser::new(bin);
+        match parser.parse::<Module<'_>>() {
+            Ok(_) => panic!("unexpected success"),
+            Err(err) => assert!(matches!(err.kind, ErrorKind::VersionMismatch(_))),
+        }
+    }
 }