Rework spying on concrete instances

spock-core/src/main/java/org/spockframework/mock/IMockConfiguration.java

@@ -35,9 +35,9 @@ public interface IMockConfiguration {
   Class<?> getType();
 
   /**
-   * Returns the instance to be used as a delegate
+   * Returns the instance to be used as a prototype
    *
-   * @return the instance to be used as a delegate
+   * @return the instance to be used as a prototype
    */
   @Nullable
   Object getInstance();

spock-core/src/main/java/org/spockframework/mock/IMockObject.java

@@ -16,7 +16,6 @@
 
 import org.spockframework.mock.runtime.SpecificationAttachable;
 import org.spockframework.util.Nullable;
-
 import spock.lang.Specification;
 
 import java.lang.reflect.Type;
@@ -51,13 +50,6 @@ public interface IMockObject extends SpecificationAttachable {
    * @return the instance of this mock object
    */
   Object getInstance();
-
-  /**
-   * Returns the original instance provided by the user for wrapping with a Spy, or {@code null} if not applicable.
-   *
-   * @return the the original instance provided by the user for wrapping with a Spy, or {@code null} if not applicable.
-   */
-  Object getUserCreatedInstance();
 
   /**
    * Tells whether this mock object supports verification of invocations.

spock-core/src/main/java/org/spockframework/mock/runtime/ByteBuddyMethodInvoker.java

@@ -1,10 +1,7 @@
 package org.spockframework.mock.runtime;
 
-import org.spockframework.mock.IMockInvocation;
-import org.spockframework.mock.IMockMethod;
-import org.spockframework.mock.IResponseGenerator;
+import org.spockframework.mock.*;
 import org.spockframework.util.ExceptionUtil;
-import org.spockframework.util.ReflectionUtil;
 
 public class ByteBuddyMethodInvoker implements IResponseGenerator {
 
@@ -20,12 +17,6 @@ public Object respond(IMockInvocation invocation) {
       throw new IllegalStateException("Cannot invoke abstract method " + invocation.getMethod());
     }
     try {
-      Object userCreatedInstance = invocation.getMockObject().getUserCreatedInstance();
-      if(userCreatedInstance != null) {
-        IMockMethod method = invocation.getMethod();
-        Class<?>[] parameterTypes = method.getParameterTypes().toArray(new Class<?>[method.getParameterTypes().size()]);
-        return  ReflectionUtil.getMethodBySignature(userCreatedInstance.getClass(), method.getName(), parameterTypes).invoke(userCreatedInstance, invocation.getArguments().toArray());
-      }
       return superCall.call(invocation.getArguments().toArray());
     } catch (Throwable t) {
       // Byte Buddy doesn't wrap exceptions in InvocationTargetException, so no need to unwrap

spock-core/src/main/java/org/spockframework/mock/runtime/CglibRealMethodInvoker.java

@@ -29,11 +29,7 @@ public CglibRealMethodInvoker(MethodProxy methodProxy) {
   @Override
   public Object respond(IMockInvocation invocation) {
     try {
-      if(invocation.getMockObject().getUserCreatedInstance() != null) {
-        return methodProxy.invoke(invocation.getMockObject().getUserCreatedInstance(), invocation.getArguments().toArray());
-      } else {
-        return methodProxy.invokeSuper(invocation.getMockObject().getInstance(), invocation.getArguments().toArray());
-      }
+      return methodProxy.invokeSuper(invocation.getMockObject().getInstance(), invocation.getArguments().toArray());
     } catch (Throwable t) {
       // MethodProxy doesn't wrap exceptions in InvocationTargetException, so no need to unwrap
       ExceptionUtil.sneakyThrow(t);

spock-core/src/main/java/org/spockframework/mock/runtime/CompositeMockFactory.java

@@ -21,7 +21,7 @@
 import java.util.*;
 
 public class CompositeMockFactory implements IMockFactory {
-  public static CompositeMockFactory INSTANCE =
+  public static final CompositeMockFactory INSTANCE =
       new CompositeMockFactory(Arrays.asList(JavaMockFactory.INSTANCE, GroovyMockFactory.INSTANCE));
 
   private final List<IMockFactory> mockFactories;

spock-core/src/main/java/org/spockframework/mock/runtime/GroovyMockFactory.java

@@ -16,15 +16,16 @@
 
 import org.spockframework.mock.*;
 import org.spockframework.runtime.GroovyRuntimeUtil;
+import org.spockframework.util.ReflectionUtil;
 import spock.lang.Specification;
 
 import java.lang.reflect.Modifier;
-import java.util.ArrayList;
+import java.util.*;
 
 import groovy.lang.*;
 
 public class GroovyMockFactory implements IMockFactory {
-  public static GroovyMockFactory INSTANCE = new GroovyMockFactory();
+  public static final GroovyMockFactory INSTANCE = new GroovyMockFactory();
 
   @Override
   public boolean canCreate(IMockConfiguration configuration) {
@@ -69,11 +70,15 @@ public void run() {
     }
 
     IProxyBasedMockInterceptor mockInterceptor = new GroovyMockInterceptor(configuration, specification, newMetaClass);
-    ArrayList<Class<?>> additionalInterfaces = new ArrayList<>(configuration.getAdditionalInterfaces());
+    List<Class<?>> additionalInterfaces = new ArrayList<>(configuration.getAdditionalInterfaces());
     additionalInterfaces.add(GroovyObject.class);
-    return ProxyBasedMockFactory.INSTANCE.create(type, additionalInterfaces,
-        configuration.getConstructorArgs(), mockInterceptor, specification.getClass().getClassLoader(),
-        configuration.isUseObjenesis());
+    Object proxy = ProxyBasedMockFactory.INSTANCE.create(type, additionalInterfaces,
+      configuration.getConstructorArgs(), mockInterceptor, specification.getClass().getClassLoader(),
+      configuration.isUseObjenesis());
+    if ((configuration.getNature() == MockNature.SPY) && (configuration.getInstance() != null)) {
+      ReflectionUtil.deepCopyFields(configuration.getInstance(), proxy);
+    }
+    return proxy;
   }
 
   private boolean isFinalClass(Class<?> type) {

spock-core/src/main/java/org/spockframework/mock/runtime/JavaMockFactory.java

@@ -18,14 +18,15 @@
 
 import org.spockframework.mock.*;
 import org.spockframework.runtime.GroovyRuntimeUtil;
+import org.spockframework.util.ReflectionUtil;
 import spock.lang.Specification;
 
 import java.lang.reflect.Modifier;
 
 import groovy.lang.MetaClass;
 
 public class JavaMockFactory implements IMockFactory {
-  public static JavaMockFactory INSTANCE = new JavaMockFactory();
+  public static final JavaMockFactory INSTANCE = new JavaMockFactory();
 
   @Override
   public boolean canCreate(IMockConfiguration configuration) {
@@ -54,9 +55,13 @@ private Object createInternal(IMockConfiguration configuration, Specification sp
 
     MetaClass mockMetaClass = GroovyRuntimeUtil.getMetaClass(configuration.getType());
     IProxyBasedMockInterceptor interceptor = new JavaMockInterceptor(configuration, specification, mockMetaClass);
-    return ProxyBasedMockFactory.INSTANCE.create(configuration.getType(), configuration.getAdditionalInterfaces(),
-        configuration.getConstructorArgs(), interceptor, classLoader,
-        configuration.isUseObjenesis());
+    Object proxy = ProxyBasedMockFactory.INSTANCE.create(configuration.getType(), configuration.getAdditionalInterfaces(),
+      configuration.getConstructorArgs(), interceptor, classLoader,
+      configuration.isUseObjenesis());
+    if ((configuration.getNature() == MockNature.SPY) && (configuration.getInstance() != null)) {
+      ReflectionUtil.deepCopyFields(configuration.getInstance(), proxy);
+    }
+    return proxy;
   }
 }
 

spock-core/src/main/java/org/spockframework/mock/runtime/JavaMockInterceptor.java

@@ -38,7 +38,7 @@ public JavaMockInterceptor(IMockConfiguration mockConfiguration, Specification s
   @Override
   public Object intercept(Object target, Method method, Object[] arguments, IResponseGenerator realMethodInvoker) {
     IMockObject mockObject = new MockObject(mockConfiguration.getName(), mockConfiguration.getExactType(),
-        target, mockConfiguration.getInstance(), mockConfiguration.isVerified(), false, mockConfiguration.getDefaultResponse(), specification, this);
+        target, mockConfiguration.isVerified(), false, mockConfiguration.getDefaultResponse(), specification, this);
 
     if (method.getDeclaringClass() == ISpockMockObject.class) {
       return mockObject;

spock-core/src/main/java/org/spockframework/mock/runtime/MockObject.java

@@ -27,7 +27,6 @@ public class MockObject implements IMockObject {
   private final String name;
   private final Type type;
   private final Object instance;
-  private final Object userCreatedInstance;
   private final boolean verified;
   private final boolean global;
   private final IDefaultResponse defaultResponse;
@@ -37,15 +36,9 @@ public class MockObject implements IMockObject {
 
   public MockObject(@Nullable String name, Type type, Object instance, boolean verified, boolean global,
       IDefaultResponse defaultResponse, Specification specification, SpecificationAttachable mockInterceptor) {
-    this(name, type, instance, null, verified, global, defaultResponse, specification, mockInterceptor);
-  }
-
-  public MockObject(@Nullable String name, Type type, Object instance, Object userCreatedInstance, boolean verified, boolean global,
-      IDefaultResponse defaultResponse, Specification specification, SpecificationAttachable mockInterceptor) {
     this.name = name;
     this.type = type;
     this.instance = instance;
-    this.userCreatedInstance = userCreatedInstance;
     this.verified = verified;
     this.global = global;
     this.defaultResponse = defaultResponse;
@@ -74,11 +67,6 @@ public Object getInstance() {
     return instance;
   }
 
-  @Override
-  public Object getUserCreatedInstance() {
-    return userCreatedInstance;
-  }
-
   @Override
   public boolean isVerified() {
     return verified;

spock-core/src/main/java/org/spockframework/util/ReflectionUtil.java

@@ -242,4 +242,29 @@ public static boolean isToStringOverridden(Class<?> valueClass) {
       return false;
     }
   }
+
+  public static void deepCopyFields(Object source, Object target) {
+    if (!source.getClass().isAssignableFrom(target.getClass())) {
+      throw new IllegalArgumentException("source and target are not compatible.");
+    }
+    Class<?> clazz = source.getClass();
+    while (!clazz.equals(Object.class)) {
+      Field[] fields = clazz.getDeclaredFields();
+      for (Field field : fields) {
+        copyField(field, source, target);
+      }
+      clazz = clazz.getSuperclass();
+    }
+  }
+
+  private static void copyField(Field field, Object source, Object target) {
+    boolean accessible = field.isAccessible();
+    field.setAccessible(true);
+    try {
+      field.set(target, field.get(source));
+    } catch (IllegalAccessException e) {
+      // ignore
+    }
+    field.setAccessible(accessible);
+  }
 }

spock-specs/src/test/groovy/org/spockframework/smoke/mock/JavaSpies.groovy

@@ -113,6 +113,19 @@ class JavaSpies extends Specification {
     result == "singing, singing"
   }
 
+  @Issue("https://github.com/spockframework/spock/issues/771")
+  def "sping on concrete instances can use partial mocking"() {
+    def person = Spy(new Person())
+
+    when:
+    def result = person.work()
+
+    then:
+    1 * person.work()
+    1 * person.getTask() >> "work"
+    result == "work, work"
+  }
+
   @Issue("https://github.com/spockframework/spock/issues/769")
   def "can spy on instances of classes with no default constructor"() {
     given:

spock-spring/src/main/java/org/spockframework/spring/mock/DelegatingInterceptor.java

@@ -105,11 +105,6 @@ public Object getInstance() {
       return null;
     }
 
-    @Override
-    public Object getUserCreatedInstance() {
-      return null;
-    }
-
     @Override
     public boolean isVerified() {
       return false;