@AliasFor potentially overrides attribute in wrong meta-annotation [SPR-13325]

[spring-projects-issues]

Sam Brannen opened SPR-13325 and commented

Status Quo

Spring Framework 4.2 introduced support for explicit attribute overrides in meta-annotations via the @AliasFor annotation.

For example, the following @MyTestConfig annotation uses @AliasFor to explicitly override the locations attribute in @ContextConfiguration, effectively renaming it.

@ContextConfiguration
public @interface MyTestConfig {

    @AliasFor(annotation = ContextConfiguration.class, attribute = "locations")
    String[] xmlFiles();
 }

@MyTestConfig works fine as long as there is not more than one meta-annotation with an attribute named locations.

In contrast, the following currently does not work.

@ContextConfiguration
@TestPropertySource(locations = "test.properties")
public @interface MyCombinedTestConfig {

    @AliasFor(annotation = ContextConfiguration.class, attribute = "locations")
    String[] xmlFiles();
}

@MyCombinedTestConfig(xmlFiles = "test.xml")
public class MyTests {
    // ...
}

The reason is that the getAliasedAttributeName(Method attribute, Class<? extends Annotation> targetAnnotationType) method in AnnotationUtils does not verify that the supplied attribute actually declares an alias for the targetAnnotationType. Consequently, a lookup for the locations attribute in @TestPropertySource on MyTests will incorrectly return "test.xml" instead of "test.properties".

Deliverables

1. Ensure that an explicit annotation attribute override configured via @AliasFor is only applied to the configured target meta-annotation.

---

Affects: 4.2 GA

Issue Links:

• Support implicit attribute aliases with @AliasFor [SPR-13345] #17929 Support implicit attribute aliases with @AliasFor ("is depended on by")

Referenced from: commits e20b47c, c8d604b

[spring-projects-issues]

Sam Brannen commented

Fixed as described in GitHub commit c8d604b:

Ensure @AliasFor overrides attribute in correct meta-annotation

Prior to this commit, an explicit override for an attribute in a meta-annotation configured via @AliasFor could potentially result in an incorrect override of an attribute of the same name but in the wrong meta-annotation.

This commit fixes the algorithm in getAliasedAttributeName(Method, Class) in AnnotationUtils by ensuring that an explicit attribute override is only applied to the configured target meta-annotation (i.e., configured via the annotation attribute in @AliasFor).