Consider projections without input properties open ones.

Closes #3164

src/main/java/org/springframework/data/projection/DefaultProjectionInformation.java

@@ -85,7 +85,7 @@ class DefaultProjectionInformation implements ProjectionInformation {
 
 	@Override
 	public boolean isClosed() {
-		return this.properties.equals(getInputProperties());
+		return hasInputProperties() && this.properties.equals(getInputProperties());
 	}
 
 	/**

src/main/java/org/springframework/data/projection/ProjectionInformation.java

@@ -18,6 +18,8 @@ package org.springframework.data.projection;
 import java.beans.PropertyDescriptor;
 import java.util.List;
 
+import org.springframework.util.CollectionUtils;
+
 /**
  * Information about a projection type.
  *
@@ -40,6 +42,17 @@ public interface ProjectionInformation {
 	 */
 	List<PropertyDescriptor> getInputProperties();
 
+	/**
+	 * Returns whether the projection has input properties. Projections without input types are typically open projections
+	 * that do not follow Java's property accessor naming.
+	 *
+	 * @return
+	 * @since 3.3.5
+	 */
+	default boolean hasInputProperties() {
+		return !CollectionUtils.isEmpty(getInputProperties());
+	}
+
 	/**
 	 * Returns whether supplying values for the properties returned via {@link #getInputProperties()} is sufficient to
 	 * create a working proxy instance. This will usually be used to determine whether the projection uses any dynamically

src/main/java/org/springframework/data/repository/query/ReturnedType.java

@@ -33,6 +33,7 @@ import org.springframework.lang.NonNull;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
+import org.springframework.util.CollectionUtils;
 import org.springframework.util.ConcurrentReferenceHashMap;
 import org.springframework.util.ObjectUtils;
 
@@ -130,9 +131,21 @@ public abstract class ReturnedType {
 	 * Returns the properties required to be used to populate the result.
 	 *
 	 * @return
+	 * @see ProjectionInformation#getInputProperties()
 	 */
 	public abstract List<String> getInputProperties();
 
+	/**
+	 * Returns whether the returned type has input properties.
+	 *
+	 * @return
+	 * @since 3.3.5
+	 * @see ProjectionInformation#hasInputProperties()
+	 */
+	public boolean hasInputProperties() {
+		return !CollectionUtils.isEmpty(getInputProperties());
+	}
+
 	/**
 	 * A {@link ReturnedType} that's backed by an interface.
 	 *