#1387 - Proper type resolution for CollectionModel post-processing.

CollectionModelProcessorWrapper erroneously returned a raw type in case a CollectionModel type assignment check failed which rendered the element type verification to always match as it's effectively compared against Object.

We're now returning null to rather proceed with the next candidate type.

Original ticket: #1379.

src/main/java/org/springframework/hateoas/server/mvc/RepresentationModelProcessorInvoker.java

@@ -430,6 +430,7 @@ public class RepresentationModelProcessorInvoker {
 		 * @param superType must not be {@literal null}.
 		 * @return
 		 */
+		@Nullable
 		private static ResolvableType getSuperType(ResolvableType source, Class<?> superType) {
 
 			Class<?> rawType = source.getRawClass();
@@ -450,7 +451,7 @@ public class RepresentationModelProcessorInvoker {
 				}
 			}
 
-			return ResolvableType.forClass(superType);
+			return null;
 		}
 	}
 

src/test/java/org/springframework/hateoas/server/mvc/RepresentationModelProcessorInvokerUnitTests.java

@@ -15,12 +15,14 @@
  */
 package org.springframework.hateoas.server.mvc;
 
+import static java.util.Collections.*;
 import static org.assertj.core.api.Assertions.*;
 
 import java.util.Collections;
 
 import org.junit.jupiter.api.Test;
 import org.springframework.hateoas.CollectionModel;
+import org.springframework.hateoas.EntityModel;
 import org.springframework.hateoas.RepresentationModel;
 import org.springframework.hateoas.server.RepresentationModelProcessor;
 
@@ -28,6 +30,7 @@ import org.springframework.hateoas.server.RepresentationModelProcessor;
  * Unit tests for {@link RepresentationModelProcessorInvoker}.
  *
  * @author Oliver Drotbohm
+ * @author Karina Pleskach
  */
 public class RepresentationModelProcessorInvokerUnitTests {
 
@@ -41,6 +44,33 @@ public class RepresentationModelProcessorInvokerUnitTests {
 				.doesNotThrowAnyException();
 	}
 
+	@Test // #1379
+	void doesNotInvokeProcessorForNonAssignableNestedEntity() {
+
+		FirstEntityProcessor processor = new FirstEntityProcessor();
+		RepresentationModelProcessorInvoker invoker = new RepresentationModelProcessorInvoker(
+				singletonList(processor));
+
+		EntityModel<SecondEntity> entityModel = EntityModel.of(new SecondEntity());
+		invoker.invokeProcessorsFor(CollectionModel.of(singleton(entityModel)));
+
+		assertThat(processor.invoked).isFalse();
+	}
+
+	@Test // #1379
+	void doesNotInvokeProcessorForNonAssignableNestedEntityOnSpecializedCollectionModel() {
+
+		FirstEntityProcessor firstProcessor = new FirstEntityProcessor();
+
+		RepresentationModelProcessorInvoker invoker = new RepresentationModelProcessorInvoker(
+				singletonList(firstProcessor));
+
+		EntityModel<SecondEntity> entityModel = EntityModel.of(new SecondEntity());
+		invoker.invokeProcessorsFor(new MyCollectionModelInheritor<>(singletonList(entityModel)));
+
+		assertThat(firstProcessor.invoked).isFalse();
+	}
+
 	// #1280
 
 	static class GenericPostProcessor<T extends GenericModel<T>> implements RepresentationModelProcessor<T> {
@@ -52,4 +82,27 @@ public class RepresentationModelProcessorInvokerUnitTests {
 	}
 
 	static class GenericModel<T extends RepresentationModel<T>> extends RepresentationModel<T> {}
+
+	static class FirstEntity {}
+
+	static class SecondEntity {};
+
+	static class FirstEntityProcessor implements RepresentationModelProcessor<CollectionModel<EntityModel<FirstEntity>>> {
+
+		boolean invoked = false;
+
+		@Override
+		public CollectionModel<EntityModel<FirstEntity>> process(CollectionModel<EntityModel<FirstEntity>> model) {
+
+			invoked = true;
+
+			return model;
+		}
+	}
+
+	static class MyCollectionModelInheritor<T> extends CollectionModel<T> {
+		public MyCollectionModelInheritor(Iterable<T> content) {
+			super(content);
+		}
+	}
 }