From f3c138258bd88e787bc965c99e2be04c9e5c4a71 Mon Sep 17 00:00:00 2001
From: Oliver Gierke <ogierke@pivotal.io>
Date: Mon, 16 Apr 2018 16:29:50 +0200
Subject: [PATCH] DATACMNS-1300 - Improved collection query detection for
 Iterables.

Previously a custom Iterable implementation would've caused QueryMethod.isCollectionQuery() to return true. We now solely rely on TypeInformation.isCollectionLike() (which checks for exact Iterable, Collection assignability and arrays) after handling potential wrapper types.
---
 .../data/repository/query/QueryMethod.java    | 15 +++++++-------
 .../query/QueryMethodUnitTests.java           | 20 +++++++++++++++++++
 2 files changed, 28 insertions(+), 7 deletions(-)

diff --git a/src/main/java/org/springframework/data/repository/query/QueryMethod.java b/src/main/java/org/springframework/data/repository/query/QueryMethod.java
index f9f782944..56f8fd2a7 100644
--- a/src/main/java/org/springframework/data/repository/query/QueryMethod.java
+++ b/src/main/java/org/springframework/data/repository/query/QueryMethod.java
@@ -154,7 +154,8 @@ public class QueryMethod {
 			Class<?> methodDomainClass = metadata.getReturnedDomainClass(method);
 
 			this.domainClass = repositoryDomainClass == null || repositoryDomainClass.isAssignableFrom(methodDomainClass)
-					? methodDomainClass : repositoryDomainClass;
+					? methodDomainClass
+					: repositoryDomainClass;
 		}
 
 		return domainClass;
@@ -186,13 +187,11 @@ public class QueryMethod {
 			return true;
 		}
 
-		if (QueryExecutionConverters.supports(unwrappedReturnType)
-				&& QueryExecutionConverters.isSingleValue(unwrappedReturnType)) {
-			return false;
+		if (QueryExecutionConverters.supports(unwrappedReturnType)) {
+			return !QueryExecutionConverters.isSingleValue(unwrappedReturnType);
 		}
 
-		return org.springframework.util.ClassUtils.isAssignable(Iterable.class, unwrappedReturnType)
-				|| unwrappedReturnType.isArray();
+		return ClassTypeInformation.from(unwrappedReturnType).isCollectionLike();
 	}
 
 	/**
@@ -285,7 +284,9 @@ public class QueryMethod {
 		Assert.notEmpty(types, "Types must not be null or empty!");
 
 		TypeInformation<?> returnType = ClassTypeInformation.fromReturnTypeOf(method);
-		returnType = QueryExecutionConverters.isSingleValue(returnType.getType()) ? returnType.getComponentType()
+
+		returnType = QueryExecutionConverters.isSingleValue(returnType.getType()) //
+				? returnType.getComponentType() //
 				: returnType;
 
 		for (Class<?> type : types) {
diff --git a/src/test/java/org/springframework/data/repository/query/QueryMethodUnitTests.java b/src/test/java/org/springframework/data/repository/query/QueryMethodUnitTests.java
index 61b9bd360..21147d383 100644
--- a/src/test/java/org/springframework/data/repository/query/QueryMethodUnitTests.java
+++ b/src/test/java/org/springframework/data/repository/query/QueryMethodUnitTests.java
@@ -38,6 +38,7 @@ import org.springframework.data.projection.ProjectionFactory;
 import org.springframework.data.projection.SpelAwareProxyProjectionFactory;
 import org.springframework.data.repository.Repository;
 import org.springframework.data.repository.core.RepositoryMetadata;
+import org.springframework.data.repository.core.support.AbstractRepositoryMetadata;
 import org.springframework.data.repository.core.support.DefaultRepositoryMetadata;
 import org.springframework.data.util.Version;
 
@@ -221,6 +222,15 @@ public class QueryMethodUnitTests {
 		assertThat(new QueryMethod(method, repositoryMetadata, factory).isCollectionQuery(), is(true));
 	}
 
+	@Test // DATACMNS-1300
+	public void doesNotConsiderMethodForIterableAggregateACollectionQuery() throws Exception {
+
+		RepositoryMetadata metadata = AbstractRepositoryMetadata.getMetadata(ContainerRepository.class);
+		Method method = ContainerRepository.class.getMethod("someMethod");
+
+		assertThat(new QueryMethod(method, metadata, factory).isCollectionQuery(), is(false));
+	}
+
 	interface SampleRepository extends Repository<User, Serializable> {
 
 		String pagingMethodWithInvalidReturnType(Pageable pageable);
@@ -274,4 +284,14 @@ public class QueryMethodUnitTests {
 	class SpecialUser extends User {
 
 	}
+
+	// DATACMNS-1300
+
+	class Element {}
+
+	abstract class Container implements Iterable<Element> {}
+
+	interface ContainerRepository extends Repository<Container, Long> {
+		Container someMethod();
+	}
 }