Fix panic in parser

CHANGELOG.md

@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## Fixed
+
+- Fixed a panic while parsing an invalid file like `{ $`.
+
 ## [0.4.0] - 2023-06-18
 
 ## Changed

protox-parse/src/parse/mod.rs

@@ -1162,9 +1162,12 @@ impl<'a> Parser<'a> {
             match self.peek() {
                 Ok(None) => return,
                 Ok(Some((tok, _))) if tokens.contains(&tok) => return,
-                _ => {
+                Ok(Some(_)) => {
                     self.bump();
                 }
+                Err(()) => {
+                    self.peek = None;
+                }
             }
         }
     }

protox-parse/src/parse/snapshots/protox_parse__parse__tests__parse_file-18.snap

@@ -0,0 +1,16 @@
+---
+source: protox-parse/src/parse/tests.rs
+expression: "if parser.lexer.extras.errors.is_empty() {\n        Ok(result.unwrap())\n    } else { Err(parser.lexer.extras.errors) }"
+---
+Err(
+    [
+        UnexpectedToken {
+            expected: "'enum', 'extend', 'import', 'message', 'option', 'service', 'package' or ';'",
+            found: "thing",
+            span: 0..5,
+        },
+        InvalidToken {
+            span: 6..7,
+        },
+    ],
+)

protox-parse/src/parse/tests.rs

@@ -410,4 +410,5 @@ pub fn parse_file() {
     case!(parse_file("syntax = 1;"));
     case!(parse_file("thing"));
     case!(parse_file("message } } } message } } }"));
+    case!(parse_file("thing $"));
 }