Add check for missing interface methods, fixes #423

resources/bytecode/javFiles/Bug422.jav

@@ -1,2 +0,0 @@
-public class Bug422 {}
-public class Bug422 {}

resources/bytecode/javFiles/Bug423.jav

@@ -0,0 +1,5 @@
+import java.lang.Integer;
+
+interface Bug423I { Integer f(); }
+
+public class Bug423 implements Bug423I { }

resources/bytecode/javFiles/Interfaces.jav

@@ -15,6 +15,7 @@ interface C {
 }
 
 class ClassX implements A {
+    void method1() {}
 }
 
 record ClassY(Integer myInt) implements C {}

src/main/java/de/dhbwstuttgart/bytecode/Codegen.java

@@ -1846,6 +1846,35 @@ public class Codegen {
         clazz.constructors().forEach(this::generateConstructor);
         clazz.methods().forEach(this::generateMethod);
 
+        // Check if non abstract class implements all interface methods
+        if ((access & ACC_ABSTRACT) == 0) {
+            for (var intf : clazz.implementingInterfaces()) {
+                var intfClass = compiler.getClass(new JavaClassName(intf.name()));
+                for (var method : intfClass.getMethods()) {
+                    if ((method.modifier & ACC_ABSTRACT) != 0) {
+                        // Check if the method is implemented in the current class
+                        // TODO This is duplicate code, we should probably refactor instances of this pattern
+                        var foundMethods = clazz.methods().stream().filter(m -> {
+                            if (!m.name().equals(method.name)) return false;
+                            if (m.signature().parameters().size() != method.getParameterList().getFormalparalist().size())
+                                return false;
+                            for (var i = 0; i < m.signature().parameters().size(); i++) {
+                                var param1 = m.signature().parameters().get(i).pattern().type();
+                                var param2 = converter.convert(
+                                    method.getParameterList().getParameterAt(i).getType(),
+                                    ASTToTargetAST.Generics.nullGenerics(compiler).javaGenerics());
+                                if (!param1.equals(param2)) return false;
+                            }
+                            return true;
+                        }).toList();
+                        if (foundMethods.size() != 1) {
+                            throw new CodeGenException("Class " + clazz.qualifiedName() + " does not implement method " + method.name + " from interface " + intfClass.getClassName());
+                        }
+                    }
+                }
+            }
+        }
+
         if (clazz.staticConstructor() != null)
             generateStaticConstructor(clazz.staticConstructor());
 

src/main/java/de/dhbwstuttgart/core/JavaTXCompiler.java

@@ -5,7 +5,6 @@ import de.dhbwstuttgart.bytecode.Codegen;
 import de.dhbwstuttgart.bytecode.FunNGenerator;
 import de.dhbwstuttgart.environment.CompilationEnvironment;
 import de.dhbwstuttgart.environment.DirectoryClassLoader;
-import de.dhbwstuttgart.exceptions.CompilerException;
 import de.dhbwstuttgart.exceptions.CompilerWarning;
 import de.dhbwstuttgart.exceptions.DebugException;
 import de.dhbwstuttgart.exceptions.WarningsException;
@@ -172,8 +171,6 @@ public class JavaTXCompiler {
 
 				var numberOfGenerics = decl == null ? 0 : decl.genericTypeVar().size();
 				var className = pkgName + (!pkgName.isEmpty() ? "." : "") + name;
-				if (classRegistry.contains(className))
-					throw new CompilerException("Duplicate class definition: " + className);
 				classRegistry.addName(className, numberOfGenerics);
 				input.add(classRegistry.getName(className));
 			}

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

@@ -1,7 +0,0 @@
-package de.dhbwstuttgart.exceptions;
-
-public class CompilerException extends RuntimeException {
-    public CompilerException(String message) {
-        super(message);
-    }
-}

src/test/java/TestComplete.java

@@ -1,8 +1,6 @@
 
 import de.dhbwstuttgart.bytecode.CodeGenException;
 import de.dhbwstuttgart.core.ConsoleInterface;
-import de.dhbwstuttgart.exceptions.CompilerException;
-import de.dhbwstuttgart.exceptions.DebugException;
 import de.dhbwstuttgart.exceptions.WarningsException;
 import de.dhbwstuttgart.util.Logger;
 import de.dhbwstuttgart.util.Logger.LogLevel;
@@ -1708,12 +1706,12 @@ public class TestComplete {
     }
 
     @Test
-    public void testBug422() throws Exception {
+    public void testBug423() throws Exception {
         try {
-            var classFiles = generateClassFiles(createClassLoader(), "Bug422.jav");
-            fail("Shouldn't compile!");
-        } catch (CompilerException e) {
-            assertEquals("Duplicate class definition: Bug422", e.getMessage());
+            var classFiles = generateClassFiles(createClassLoader(), "Bug423.jav");
+            fail("No exception thrown!");
+        } catch (CodeGenException e) {
+            assertEquals("Class Bug423 does not implement method f from interface Bug423I", e.getMessage());
         }
     }
 }