Fix #421 by adding error listeners to the Parser & Lexer

resources/bytecode/javFiles/Bug421.jav

@@ -0,0 +1,3 @@
+public class Bug421 {
+    public m() { return 1 } // Missing semicolon
+}

src/main/java/de/dhbwstuttgart/exceptions/ParserError.java

@@ -2,9 +2,8 @@ package de.dhbwstuttgart.exceptions;
 
 import org.antlr.v4.runtime.Token;
 
-public class ParserError extends TypeinferenceException{
-
-	public ParserError(Token offset){
-		super("Fehler beim Parsen", offset);
+public class ParserError extends RuntimeException{
+	public ParserError(String message) {
+		super(message);
 	}
 }

src/main/java/de/dhbwstuttgart/parser/JavaTXParser.java

@@ -1,6 +1,7 @@
 package de.dhbwstuttgart.parser;
 
 import de.dhbwstuttgart.environment.CompilationEnvironment;
+import de.dhbwstuttgart.exceptions.ParserError;
 import de.dhbwstuttgart.parser.SyntaxTreeGenerator.SyntaxTreeGenerator;
 import de.dhbwstuttgart.parser.antlr.Java17Lexer;
 import de.dhbwstuttgart.parser.antlr.Java17Parser;
@@ -8,9 +9,7 @@ import de.dhbwstuttgart.parser.scope.JavaClassRegistry;
 import de.dhbwstuttgart.syntaxtree.SourceFile;
 
 import de.dhbwstuttgart.util.Logger;
-import org.antlr.v4.runtime.CharStream;
-import org.antlr.v4.runtime.CharStreams;
-import org.antlr.v4.runtime.CommonTokenStream;
+import org.antlr.v4.runtime.*;
 
 import java.io.*;
 import java.nio.charset.StandardCharsets;
@@ -21,13 +20,25 @@ public class JavaTXParser {
 
     public static Logger logger = new Logger("Parser");
 
+    public static class ThrowingErrorListener extends BaseErrorListener {
+
+        @Override
+        public void syntaxError(Recognizer<?, ?> recognizer, Object offendingSymbol,
+                                int line, int charPositionInLine, String msg, RecognitionException e) {
+            throw new ParserError("Syntax error at line " + line +  ":" + charPositionInLine + " - " + msg);
+        }
+    }
+
     public static Java17Parser.SourceFileContext parse(File source) throws IOException, java.lang.ClassNotFoundException {
         InputStream stream = new FileInputStream(source);
         // DEPRECATED: ANTLRInputStream input = new ANTLRInputStream(stream);
+        var errorListener = new ThrowingErrorListener();
         CharStream input = CharStreams.fromStream(stream);
         Java17Lexer lexer = new Java17Lexer(input);
+        lexer.addErrorListener(errorListener);
         CommonTokenStream tokens = new CommonTokenStream(lexer);
         Java17Parser parser = new Java17Parser(tokens);
+        parser.addErrorListener(errorListener);
         return parser.sourceFile();
         /*
          * SyntaxTreeGenerator generator = new SyntaxTreeGenerator(environment.getRegistry(source)); return generator.convert(tree);

src/test/java/TestComplete.java

@@ -1,6 +1,7 @@
 
 import de.dhbwstuttgart.bytecode.CodeGenException;
 import de.dhbwstuttgart.core.ConsoleInterface;
+import de.dhbwstuttgart.exceptions.ParserError;
 import de.dhbwstuttgart.exceptions.WarningsException;
 import de.dhbwstuttgart.util.Logger;
 import de.dhbwstuttgart.util.Logger.LogLevel;
@@ -1704,4 +1705,14 @@ public class TestComplete {
         var clazz = classFiles.get("Bug406");
         clazz.getDeclaredMethod("main", List.class).invoke(null, List.of());
     }
+
+    @Test
+    public void testBug421() throws Exception {
+        try {
+            var classFiles = generateClassFiles(createClassLoader(), "Bug421.jav");
+            fail("Shouldn't compile!");
+        } catch (ParserError e) {
+            assertEquals("Syntax error at line 2:26 - no viable alternative at input 'm() { return 1 }'", e.getMessage());
+        }
+    }
 }