Report code coverage correctly for Kotlin methods with default arguments

org.jacoco.core.test.validation.kotlin/src/org/jacoco/core/test/validation/kotlin/KotlinDefaultArgumentsTest.java

@@ -0,0 +1,26 @@
+/*******************************************************************************
+ * Copyright (c) 2009, 2018 Mountainminds GmbH & Co. KG and Contributors
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *    Evgeny Mandrikov - initial API and implementation
+ *
+ *******************************************************************************/
+package org.jacoco.core.test.validation.kotlin;
+
+import org.jacoco.core.test.validation.ValidationTestBase;
+import org.jacoco.core.test.validation.kotlin.targets.KotlinDefaultArgumentsTarget;
+
+/**
+ * Test of functions with default arguments.
+ */
+public class KotlinDefaultArgumentsTest extends ValidationTestBase {
+
+	public KotlinDefaultArgumentsTest() {
+		super(KotlinDefaultArgumentsTarget.class);
+	}
+
+}

org.jacoco.core.test.validation.kotlin/src/org/jacoco/core/test/validation/kotlin/targets/KotlinDefaultArgumentsTarget.kt

@@ -0,0 +1,36 @@
+/*******************************************************************************
+ * Copyright (c) 2009, 2018 Mountainminds GmbH & Co. KG and Contributors
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *    Evgeny Mandrikov - initial API and implementation
+ *
+ *******************************************************************************/
+package org.jacoco.core.test.validation.kotlin.targets
+
+/**
+ * Test target for functions with default arguments.
+ */
+object KotlinDefaultArgumentsTarget {
+
+    private fun f(a: String = "a", b: String = "b") { // assertFullyCovered(0, 0)
+    }
+
+    private fun branch(a: Boolean, b: String = if (a) "a" else "b") { // assertFullyCovered(0, 2)
+    }
+
+    @JvmStatic
+    fun main(args: Array<String>) {
+        f(a = "a")
+        f(b = "b")
+        /* next invocation doesn't use synthetic method: */
+        f("a", "b")
+
+        branch(false)
+        branch(true)
+    }
+
+}

org.jacoco.core.test/src/org/jacoco/core/internal/analysis/filter/KotlinDefaultArgumentsFilterTest.java

@@ -0,0 +1,98 @@
+/*******************************************************************************
+ * Copyright (c) 2009, 2018 Mountainminds GmbH & Co. KG and Contributors
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *    Evgeny Mandrikov - initial API and implementation
+ *
+ *******************************************************************************/
+package org.jacoco.core.internal.analysis.filter;
+
+import org.jacoco.core.internal.instr.InstrSupport;
+import org.junit.Test;
+import org.objectweb.asm.Label;
+import org.objectweb.asm.Opcodes;
+import org.objectweb.asm.tree.MethodNode;
+
+/**
+ * Unit test for {@link KotlinDefaultArgumentsFilter}.
+ */
+public class KotlinDefaultArgumentsFilterTest extends FilterTestBase {
+
+	private final IFilter filter = new KotlinDefaultArgumentsFilter();
+
+	private static MethodNode createMethod(final int access, final String name,
+			final String descriptor) {
+		final MethodNode m = new MethodNode(InstrSupport.ASM_API_VERSION,
+				access, name, descriptor, null, null);
+
+		m.visitVarInsn(Opcodes.ILOAD, 2);
+		m.visitInsn(Opcodes.ICONST_1);
+		m.visitInsn(Opcodes.IAND);
+		final Label label = new Label();
+		m.visitJumpInsn(Opcodes.IFEQ, label);
+		// default argument
+		m.visitLdcInsn(Integer.valueOf(42));
+		m.visitVarInsn(Opcodes.ISTORE, 1);
+		m.visitLabel(label);
+
+		m.visitVarInsn(Opcodes.ALOAD, 0);
+		m.visitVarInsn(Opcodes.ILOAD, 1);
+		m.visitMethodInsn(Opcodes.INVOKESPECIAL, "Target", "origin", "(I)V",
+				false);
+		m.visitInsn(Opcodes.RETURN);
+
+		return m;
+	}
+
+	@Test
+	public void should_filter() {
+		final MethodNode m = createMethod(Opcodes.ACC_SYNTHETIC,
+				"origin$default", "(LTarget;IILjava/lang/Object;)V");
+		context.classAnnotations
+				.add(KotlinGeneratedFilter.KOTLIN_METADATA_DESC);
+
+		filter.filter(m, context, output);
+
+		assertIgnored(new Range(m.instructions.get(3), m.instructions.get(3)));
+	}
+
+	@Test
+	public void should_not_filter_when_not_kotlin() {
+		final MethodNode m = createMethod(Opcodes.ACC_SYNTHETIC,
+				"not_kotlin_synthetic$default",
+				"(LTarget;IILjava/lang/Object;)V");
+
+		filter.filter(m, context, output);
+
+		assertIgnored();
+	}
+
+	@Test
+	public void should_not_filter_when_suffix_absent() {
+		final MethodNode m = createMethod(Opcodes.ACC_SYNTHETIC,
+				"synthetic_without_suffix", "(LTarget;IILjava/lang/Object;)V");
+		context.classAnnotations
+				.add(KotlinGeneratedFilter.KOTLIN_METADATA_DESC);
+
+		filter.filter(m, context, output);
+
+		assertIgnored();
+	}
+
+	@Test
+	public void should_not_filter_when_not_synthetic() {
+		final MethodNode m = createMethod(0, "not_synthetic$default",
+				"(LTarget;IILjava/lang/Object;)V");
+		context.classAnnotations
+				.add(KotlinGeneratedFilter.KOTLIN_METADATA_DESC);
+
+		filter.filter(m, context, output);
+
+		assertIgnored();
+	}
+
+}

org.jacoco.core.test/src/org/jacoco/core/internal/analysis/filter/SyntheticFilterTest.java

@@ -56,4 +56,30 @@ public void testLambda() {
 		assertIgnored();
 	}
 
+	@Test
+	public void should_not_filter_method_with_suffix_default_in_kotlin_classes() {
+		final MethodNode m = new MethodNode(InstrSupport.ASM_API_VERSION,
+				Opcodes.ACC_SYNTHETIC | Opcodes.ACC_BRIDGE, "example$default",
+				"(LTarget;Ljava/lang/String;Ijava/lang/Object;)V", null, null);
+		context.classAnnotations
+				.add(KotlinGeneratedFilter.KOTLIN_METADATA_DESC);
+		m.visitInsn(Opcodes.NOP);
+
+		filter.filter(m, context, output);
+
+		assertIgnored();
+	}
+
+	@Test
+	public void should_filter_synthetic_method_with_suffix_default_in_non_kotlin_classes() {
+		final MethodNode m = new MethodNode(InstrSupport.ASM_API_VERSION,
+				Opcodes.ACC_SYNTHETIC | Opcodes.ACC_BRIDGE, "example$default",
+				"(LTarget;Ljava/lang/String;Ijava/lang/Object;)V", null, null);
+		m.visitInsn(Opcodes.NOP);
+
+		filter.filter(m, context, output);
+
+		assertMethodIgnored(m);
+	}
+
 }

org.jacoco.core/src/org/jacoco/core/internal/analysis/filter/AbstractMatcher.java

@@ -154,7 +154,11 @@ final void next() {
 		skipNonOpcodes();
 	}
 
-	private void skipNonOpcodes() {
+	/**
+	 * Moves {@link #cursor} through {@link AbstractInsnNode#FRAME},
+	 * {@link AbstractInsnNode#LABEL}, {@link AbstractInsnNode#LINE}.
+	 */
+	final void skipNonOpcodes() {
 		while (cursor != null && (cursor.getType() == AbstractInsnNode.FRAME
 				|| cursor.getType() == AbstractInsnNode.LABEL
 				|| cursor.getType() == AbstractInsnNode.LINE)) {

org.jacoco.core/src/org/jacoco/core/internal/analysis/filter/Filters.java

@@ -35,7 +35,8 @@ public final class Filters implements IFilter {
 			new EnumEmptyConstructorFilter(), new AnnotationGeneratedFilter(),
 			new KotlinGeneratedFilter(), new KotlinLateinitFilter(),
 			new KotlinWhenFilter(), new KotlinWhenStringFilter(),
-			new KotlinUnsafeCastOperatorFilter());
+			new KotlinUnsafeCastOperatorFilter(),
+			new KotlinDefaultArgumentsFilter());
 
 	private final IFilter[] filters;
 

org.jacoco.core/src/org/jacoco/core/internal/analysis/filter/KotlinDefaultArgumentsFilter.java

@@ -0,0 +1,97 @@
+/*******************************************************************************
+ * Copyright (c) 2009, 2018 Mountainminds GmbH & Co. KG and Contributors
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *    Evgeny Mandrikov - initial API and implementation
+ *
+ *******************************************************************************/
+package org.jacoco.core.internal.analysis.filter;
+
+import java.util.HashSet;
+import java.util.Set;
+
+import org.objectweb.asm.Opcodes;
+import org.objectweb.asm.Type;
+import org.objectweb.asm.tree.AbstractInsnNode;
+import org.objectweb.asm.tree.JumpInsnNode;
+import org.objectweb.asm.tree.MethodNode;
+import org.objectweb.asm.tree.VarInsnNode;
+
+/**
+ * Filters branches that Kotlin compiler generates for default arguments.
+ * 
+ * For each default argument Kotlin compiler generates following bytecode to
+ * determine if it should be used or not:
+ * 
+ * <pre>
+ * ILOAD maskVar
+ * ICONST_x, BIPUSH, SIPUSH, LDC or LDC_W
+ * IAND
+ * IFEQ label
+ * default argument
+ * label:
+ * </pre>
+ * 
+ * Where <code>maskVar</code> is penultimate argument of synthetic method with
+ * suffix "$default". And its value can't be zero - invocation with all
+ * arguments uses original non synthetic method, thus <code>IFEQ</code>
+ * instructions should be ignored.
+ */
+public final class KotlinDefaultArgumentsFilter implements IFilter {
+
+	static boolean isDefaultArgumentsMethodName(final String methodName) {
+		return methodName.endsWith("$default");
+	}
+
+	public void filter(final MethodNode methodNode,
+			final IFilterContext context, final IFilterOutput output) {
+		if ((methodNode.access & Opcodes.ACC_SYNTHETIC) == 0) {
+			return;
+		}
+		if (!isDefaultArgumentsMethodName(methodNode.name)) {
+			return;
+		}
+		if (!KotlinGeneratedFilter.isKotlinClass(context)) {
+			return;
+		}
+
+		new Matcher().match(methodNode, output);
+	}
+
+	private static class Matcher extends AbstractMatcher {
+		public void match(final MethodNode methodNode,
+				final IFilterOutput output) {
+			cursor = methodNode.instructions.getFirst();
+
+			final Set<AbstractInsnNode> ignore = new HashSet<AbstractInsnNode>();
+			final int maskVar = Type.getMethodType(methodNode.desc)
+					.getArgumentTypes().length - 2;
+			while (true) {
+				if (cursor.getOpcode() != Opcodes.ILOAD) {
+					break;
+				}
+				if (((VarInsnNode) cursor).var != maskVar) {
+					break;
+				}
+				next();
+				nextIs(Opcodes.IAND);
+				nextIs(Opcodes.IFEQ);
+				if (cursor == null) {
+					return;
+				}
+				ignore.add(cursor);
+				cursor = ((JumpInsnNode) cursor).label;
+				skipNonOpcodes();
+			}
+
+			for (AbstractInsnNode i : ignore) {
+				output.ignore(i, i);
+			}
+		}
+	}
+
+}

org.jacoco.core/src/org/jacoco/core/internal/analysis/filter/KotlinGeneratedFilter.java

@@ -23,6 +23,10 @@ public class KotlinGeneratedFilter implements IFilter {
 
 	static final String KOTLIN_METADATA_DESC = "Lkotlin/Metadata;";
 
+	static boolean isKotlinClass(final IFilterContext context) {
+		return context.getClassAnnotations().contains(KOTLIN_METADATA_DESC);
+	}
+
 	public void filter(final MethodNode methodNode,
 			final IFilterContext context, final IFilterOutput output) {
 
@@ -32,7 +36,7 @@ public void filter(final MethodNode methodNode,
 			return;
 		}
 
-		if (!context.getClassAnnotations().contains(KOTLIN_METADATA_DESC)) {
+		if (!isKotlinClass(context)) {
 			return;
 		}
 

org.jacoco.core/src/org/jacoco/core/internal/analysis/filter/SyntheticFilter.java

@@ -21,11 +21,22 @@ public final class SyntheticFilter implements IFilter {
 
 	public void filter(final MethodNode methodNode,
 			final IFilterContext context, final IFilterOutput output) {
-		if ((methodNode.access & Opcodes.ACC_SYNTHETIC) != 0
-				&& !methodNode.name.startsWith("lambda$")) {
-			output.ignore(methodNode.instructions.getFirst(),
-					methodNode.instructions.getLast());
+		if ((methodNode.access & Opcodes.ACC_SYNTHETIC) == 0) {
+			return;
 		}
+
+		if (methodNode.name.startsWith("lambda$")) {
+			return;
+		}
+
+		if (KotlinDefaultArgumentsFilter
+				.isDefaultArgumentsMethodName(methodNode.name)
+				&& KotlinGeneratedFilter.isKotlinClass(context)) {
+			return;
+		}
+
+		output.ignore(methodNode.instructions.getFirst(),
+				methodNode.instructions.getLast());
 	}
 
 }

org.jacoco.doc/docroot/doc/changes.html

@@ -29,6 +29,12 @@ <h3>New Features</h3>
       (GitHub <a href="https://github.com/jacoco/jacoco/issues/761">#761</a>).</li>
 </ul>
 
+<h3>Fixed Bugs</h3>
+<ul>
+  <li>Report code coverage correctly for Kotlin methods with default arguments
+      (GitHub <a href="https://github.com/jacoco/jacoco/issues/774">#774</a>).</li>
+</ul>
+
 <h3>Non-functional Changes</h3>
 <ul>
   <li>JaCoCo now depends on ASM 7.0