[LANG-1420] TypeUtils.isAssignable returns wrong result for GenericArrayType and ParameterizedType

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.7, 3.8
• Fix Version/s: 3.12.0
• Component/s: lang.reflect.*
• Assignee: Unassigned
• Reporter: Gordon Fraser
• Created: 13/Sep/18 08:05
• Updated: 15/Nov/20 16:50
• Resolved: 15/Nov/20 16:50

Description

TypeUtils.isAssignable returns a wrong result when checking whether a ParameterizedType is assignable to a GenericArrayType that has the same ParameterizedType as component type.

For example:

ParameterizedType componentType = TypeUtils.parameterize(java.lang.reflect.Constructor.class, java.awt.Insets.class);
GenericArrayType arrayType = TypeUtils.genericArrayType(componentType);

In this case,

TypeUtils.isAssignable(arrayType, componentType) 

returns true, but this should be false (the component type should not be assignable to the array type - the Java compiler complains about this).

 

It seem that the problem is that the method:

private static boolean isAssignable(final Type type, final ParameterizedType toParameterizedType, final Map<TypeVariable<?>, Type> typeVarAssigns)

only compares the type parameters, since method getTypeArguments retrieves the component type using getGenericComponentType. There seems to be no check whether an array type is being assigned to a non-array in the first place.

Issue Links

• links to: LANG-1420 - TypeUtils.isAssignable returns wrong result for GenericAr… #643