DATACMNS-422 - Mitigate semantic changes in Spring 4.0's GenericTypeResolver.

In case of an unresolvable generic parameter in TypeDiscoverer's getTypeArgument(…) we check for a generic super type for the given bound and fall back to Object in case we find a parameterized type.

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2011-2013 the original author or authors.
+ * Copyright 2011-2014 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -309,7 +309,7 @@ class TypeDiscoverer<S> implements TypeInformation<S> {
 	public TypeInformation<?> getMapValueType() {
 
 		if (isMap()) {
-			return getTypeArgument(getType(), Map.class, 1);
+			return getTypeArgument(Map.class, 1);
 		}
 
 		List<TypeInformation<?>> arguments = getTypeArguments();
@@ -349,11 +349,11 @@ class TypeDiscoverer<S> implements TypeInformation<S> {
 		}
 
 		if (isMap()) {
-			return getTypeArgument(rawType, Map.class, 0);
+			return getTypeArgument(Map.class, 0);
 		}
 
 		if (Iterable.class.isAssignableFrom(rawType)) {
-			return getTypeArgument(rawType, Iterable.class, 0);
+			return getTypeArgument(Iterable.class, 0);
 		}
 
 		List<TypeInformation<?>> arguments = getTypeArguments();
@@ -449,9 +449,16 @@ class TypeDiscoverer<S> implements TypeInformation<S> {
 		return target.getSuperTypeInformation(getType()).equals(this);
 	}
 
-	private TypeInformation<?> getTypeArgument(Class<?> type, Class<?> bound, int index) {
-		Class<?>[] arguments = GenericTypeResolver.resolveTypeArguments(type, bound);
-		return arguments == null ? null : createInfo(arguments[index]);
+	private TypeInformation<?> getTypeArgument(Class<?> bound, int index) {
+
+		Class<?>[] arguments = GenericTypeResolver.resolveTypeArguments(getType(), bound);
+
+		if (arguments == null) {
+			return getSuperTypeInformation(bound) instanceof ParameterizedTypeInformation ? ClassTypeInformation.OBJECT
+					: null;
+		}
+
+		return createInfo(arguments[index]);
 	}
 
 	/*

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2011-2013 the original author or authors.
+ * Copyright 2011-2014 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -285,6 +285,16 @@ public class ClassTypeInformationUnitTests {
 		from(null);
 	}
 
+	/**
+	 * @see DATACMNS-422
+	 */
+	@Test
+	public void returnsNullForRawTypesOnly() {
+
+		assertThat(from(MyRawIterable.class).getComponentType(), is(nullValue()));
+		assertThat(from(MyIterable.class).getComponentType(), is(notNullValue()));
+	}
+
 	static class StringMapContainer extends MapContainer<String> {
 
 	}
@@ -409,4 +419,9 @@ public class ClassTypeInformationUnitTests {
 	interface Identifiable {
 		Long getId();
 	}
+
+	@SuppressWarnings("rawtypes")
+	interface MyRawIterable extends Iterable {}
+
+	interface MyIterable<T> extends Iterable<T> {}
 }