MethodInvocationRecorder now supports traversing primitive properties.

We now return a default value for invocations of methods returning a primitive value to pass the AOP infrastructure's check for compatible values. Before, that barked at the null value returned for the invocation.

Fixes spring-projects#2612.

Author: odrotbohm

src/main/java/org/springframework/data/util/MethodInvocationRecorder.java

@@ -15,6 +15,7 @@
  */
 package org.springframework.data.util;
 
+import java.lang.reflect.Array;
 import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;
 import java.util.Arrays;
@@ -158,7 +159,7 @@ private Optional<String> getPropertyPath(List<PropertyNameDetectionStrategy> str
 
 		private InvocationInformation registerInvocation(Method method, Class<?> proxyType) {
 
-			Recorded<?> create = Modifier.isFinal(proxyType.getModifiers()) ? new Unrecorded() : create(proxyType);
+			Recorded<?> create = Modifier.isFinal(proxyType.getModifiers()) ? new Unrecorded(proxyType) : create(proxyType);
 			InvocationInformation information = new InvocationInformation(create, method);
 
 			return this.information = information;
@@ -167,7 +168,7 @@ private InvocationInformation registerInvocation(Method method, Class<?> proxyTy
 
 	private static final class InvocationInformation {
 
-		private static final InvocationInformation NOT_INVOKED = new InvocationInformation(new Unrecorded(), null);
+		private static final InvocationInformation NOT_INVOKED = new InvocationInformation(new Unrecorded(null), null);
 
 		private final Recorded<?> recorded;
 		private final @Nullable Method invokedMethod;
@@ -251,7 +252,7 @@ public int hashCode() {
 
 			int result = ObjectUtils.nullSafeHashCode(recorded);
 
-			result = 31 * result + ObjectUtils.nullSafeHashCode(invokedMethod);
+			result = (31 * result) + ObjectUtils.nullSafeHashCode(invokedMethod);
 
 			return result;
 		}
@@ -386,8 +387,8 @@ public interface ToMapConverter<T, S> extends Function<T, Map<?, S>> {}
 
 	static class Unrecorded extends Recorded<Object> {
 
-		private Unrecorded() {
-			super(null, null);
+		private Unrecorded(@Nullable Class<?> type) {
+			super(type == null ? null : type.isPrimitive() ? getDefaultValue(type) : null, null);
 		}
 
 		/*
@@ -398,5 +399,9 @@ private Unrecorded() {
 		public Optional<String> getPropertyPath(List<PropertyNameDetectionStrategy> strategies) {
 			return Optional.empty();
 		}
+
+		private static Object getDefaultValue(Class<?> clazz) {
+			return Array.get(Array.newInstance(clazz, 1), 0);
+		}
 	}
 }

src/test/java/org/springframework/data/util/MethodInvocationRecorderUnitTests.java

@@ -86,13 +86,22 @@ void recordsInvocationOnInterface() {
 		assertThat(recorder.record(Sample::getName).getPropertyPath()).hasValue("name");
 	}
 
+	@Test // #2612
+	void registersLookupForPrimitiveValue() {
+
+		Recorded<Foo> recorder = MethodInvocationRecorder.forProxyOf(Foo.class);
+
+		assertThat(recorder.record(Foo::getAge).getPropertyPath()).hasValue("age");
+	}
+
 	static final class FinalType {}
 
 	@Getter
 	static class Foo {
 		Bar bar;
 		Collection<Bar> bars;
 		String name;
+		int age;
 	}
 
 	@Getter