Miklós Győrfi created WICKET-7086:
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Summary: Injecting Spring bean may cause ClassCastException
Key: WICKET-7086
URL: https://issues.apache.org/jira/browse/WICKET-7086
Project: Wicket
Issue Type: Bug
Components: wicket-spring
Affects Versions: 9.15.0
Reporter: Miklós Győrfi
h3. Issue Summary:
The {{getBeanNameOfClass()}} method used for injecting Spring beans into Wicket
components has a limitation when dealing with generic collection fields. The
method is designed to look up a bean name based on the raw type of the
collection (e.g., {{{}List{}}}). However, in scenarios where there are beans
with more specific generic types (e.g., {{{}List<SomeClass>{}}}), the method
incorrectly resolves and injects the bean, leading to potential
{{ClassCastException}} issues at runtime.
h3. Problem Details:
When the field class is a generic collection (e.g., {{{}List<AnyClass>{}}}),
the {{getBeanNameOfClass()}} method resolves a bean with the type of the raw
collection (e.g., {{{}List{}}}). This behavior generally works as intended.
However, when there are beans with more specific generic types (e.g.,
{{{}List<SomeClass>{}}}), the method incorrectly identifies and injects the
bean, even if the generic types ({{{}SomeClass{}}} and {{{}AnyClass{}}}) do not
match. This results in unexpected behavior and may cause {{ClassCastException}}
errors later in the application.
h3. Reproduction Scenario:
This issue becomes apparent when using Apache Causeway in conjunction with
Spring Data REST. There is a bean named {{defaultMessageConverters}} (wich is
a List) is inserted into {{CausewayWicketApplication}} within the
{{applicationInitializers}} field, it is erroneously resolved based on the raw
type, leading to improper injection.
h3. Proposed Solution:
Review and enhance the {{getBeanNameOfClass()}} method to consider generic
types more accurately, ensuring that beans are resolved based on compatibility
with the field's specific generic type.
Problem is here:
{code:java}
List<String> names = new ArrayList<>(
Arrays.asList(BeanFactoryUtils.beanNamesForTypeIncludingAncestors(ctx,
clazz)));
{code}
It uses the clazz, without generic.
Possible solution:
{code:java}
ResolvableType resolvableType = generic != null ?
ResolvableType.forClassWithGenerics(clazz, generic) :
ResolvableType.forClass(clazz);
List<String> names = new ArrayList<>(
Arrays.asList(BeanFactoryUtils.beanNamesForTypeIncludingAncestors(ctx,
resolvableType)));
{code}
It is compatible with Spring from 4.2.
h3. Additional Context:
This problem affects scenarios where generic collections are used in
Spring-Wicket integration, and it becomes particularly prominent when Apache
Causeway is utilized alongside Spring Data REST.
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