Avoid depending on mutable fields in MethodSelector.equals()

Author: marcphilipp

junit-platform-engine/src/main/java/org/junit/platform/engine/discovery/MethodSelector.java

@@ -64,6 +64,7 @@ public final class MethodSelector implements DiscoverySelector {
 	private final String className;
 	private final String methodName;
 	private final String parameterTypeNames;
+	private final @Nullable String declaringClassName;
 
 	private volatile @Nullable Class<?> javaClass;
 
@@ -75,51 +76,51 @@ public final class MethodSelector implements DiscoverySelector {
 	 * @since 1.10
 	 */
 	MethodSelector(@Nullable ClassLoader classLoader, String className, String methodName, String parameterTypeNames) {
-		this.classLoader = classLoader;
-		this.className = className;
-		this.methodName = methodName;
-		this.parameterTypeNames = parameterTypeNames;
+		this(classLoader, className, methodName, parameterTypeNames, null);
 	}
 
 	MethodSelector(Class<?> javaClass, String methodName, String parameterTypeNames) {
-		this.classLoader = javaClass.getClassLoader();
+		this(javaClass.getClassLoader(), javaClass.getName(), methodName, parameterTypeNames, null);
 		this.javaClass = javaClass;
-		this.className = javaClass.getName();
-		this.methodName = methodName;
-		this.parameterTypeNames = parameterTypeNames;
 	}
 
 	/**
 	 * @since 1.10
 	 */
 	MethodSelector(@Nullable ClassLoader classLoader, String className, String methodName, Class<?>... parameterTypes) {
-		this.classLoader = classLoader;
-		this.className = className;
-		this.methodName = methodName;
+		this(classLoader, className, methodName, ClassUtils.nullSafeToString(Class::getTypeName, parameterTypes), null);
 		this.parameterTypes = parameterTypes.clone();
-		this.parameterTypeNames = ClassUtils.nullSafeToString(Class::getTypeName, this.parameterTypes);
 	}
 
 	/**
 	 * @since 1.10
 	 */
 	MethodSelector(Class<?> javaClass, String methodName, Class<?>... parameterTypes) {
-		this.classLoader = javaClass.getClassLoader();
+		this(javaClass.getClassLoader(), javaClass.getName(), methodName,
+			ClassUtils.nullSafeToString(Class::getTypeName, parameterTypes), null);
 		this.javaClass = javaClass;
-		this.className = javaClass.getName();
-		this.methodName = methodName;
 		this.parameterTypes = parameterTypes.clone();
-		this.parameterTypeNames = ClassUtils.nullSafeToString(Class::getTypeName, this.parameterTypes);
 	}
 
 	MethodSelector(Class<?> javaClass, Method method) {
-		this.classLoader = javaClass.getClassLoader();
+		this(javaClass, method, method.getParameterTypes());
+	}
+
+	private MethodSelector(Class<?> javaClass, Method method, Class<?>... parameterTypes) {
+		this(javaClass.getClassLoader(), javaClass.getName(), method.getName(),
+			ClassUtils.nullSafeToString(Class::getTypeName, parameterTypes), method.getDeclaringClass().getName());
 		this.javaClass = javaClass;
-		this.className = javaClass.getName();
 		this.javaMethod = method;
-		this.methodName = method.getName();
-		this.parameterTypes = method.getParameterTypes();
-		this.parameterTypeNames = ClassUtils.nullSafeToString(Class::getTypeName, this.parameterTypes);
+		this.parameterTypes = parameterTypes;
+	}
+
+	private MethodSelector(@Nullable ClassLoader classLoader, String className, String methodName,
+			String parameterTypeNames, @Nullable String declaringClassName) {
+		this.classLoader = classLoader;
+		this.className = className;
+		this.methodName = methodName;
+		this.parameterTypeNames = parameterTypeNames;
+		this.declaringClassName = declaringClassName;
 	}
 
 	/**
@@ -275,17 +276,10 @@ public boolean equals(Object o) {
 			return false;
 		}
 		MethodSelector that = (MethodSelector) o;
-		var equal = Objects.equals(this.className, that.className)//
+		return Objects.equals(this.className, that.className)//
 				&& Objects.equals(this.methodName, that.methodName)//
-				&& Objects.equals(this.parameterTypeNames, that.parameterTypeNames);
-		if (equal) {
-			var thisJavaMethod = this.javaMethod;
-			var thatJavaMethod = that.javaMethod;
-			if (thisJavaMethod != null && thatJavaMethod != null) {
-				return thisJavaMethod.equals(thatJavaMethod);
-			}
-		}
-		return equal;
+				&& Objects.equals(this.parameterTypeNames, that.parameterTypeNames)//
+				&& Objects.equals(this.declaringClassName, that.declaringClassName);
 	}
 
 	/**
@@ -294,7 +288,7 @@ public boolean equals(Object o) {
 	@API(status = STABLE, since = "1.3")
 	@Override
 	public int hashCode() {
-		return Objects.hash(this.className, this.methodName, this.parameterTypeNames);
+		return Objects.hash(this.className, this.methodName, this.parameterTypeNames, this.declaringClassName);
 	}
 
 	@Override