Doc: @PropertySource meta-annotation not detected next to direct annotation [SPR-16592]

[spring-projects-issues]

Evgeny Naku opened SPR-16592 and commented

Check out sample bug project on github: https://github.com/0v1se/spring-properties-bug

@PropertySource is not used when it's defined in other annotation.

For example, I have

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@PropertySource("app1.properties")
public @interface IncludeApp1Properties {
}

Then I have configuration:

@Configuration
@IncludeApp1Properties
@PropertySource("app2.properties")
public class ErrorConfiguration {
    @Value("${intValue1}")
    private int value1;
    @Value("${intValue2}")
    private int value2;
}

When I try to use ErrorConfiguration, there is an error Caused by: java.lang.NumberFormatException: For input string: intValue1

But when I try to use @PropertySource directly, everything is fine:

@Configuration
@PropertySource("app1.properties")
@PropertySource("app2.properties")
public class OkConfiguration {
    @Value("${intValue1}")
    private int value1;
    @Value("${intValue2}")
    private int value2;
}

---

Affects: 4.3.14, 5.0.3

Reference URL: https://github.com/0v1se/spring-properties-bug

Backported to: 4.3.15

[spring-projects-issues]

Juergen Hoeller commented

I'm afraid this is a known limitation: A direct @PropertySource annotation effectively overrides any meta-annotations. The only way to apply multiple property source annotations is to declare several @PropertySource annotations at the same level (directly on the same class or all on the same custom annotation), or to split your custom @PropertySource annotations onto several configuration classes (one each).

In any case, we have to document this, so I've turned this into a documentation ticket.

[spring-projects-issues]

Evgeny Naku commented

Thanks for documenting this.

Just a note:
Unfortunately, the same applies for other repeated annotations. For example, @ComponentScan.
So, I can't have something like this:

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@ComponentScan
.....
public @interface EnableDatabase {
    @AliasFor(annotation = ComponentScan.class, attribute = "basePackageClasses")
    Class<?>[] scanPackage() default {};
}

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@ComponentScan
.....
public @interface EnableController {
    @AliasFor(annotation = ComponentScan.class, attribute = "basePackageClasses")
    Class<?>[] scanPackage() default {};
}

@EnableDatabase(scanPackage = Database.class)
@EnableController(scanPackage = Controller.class)
public class Configuration {
}

Spring will scan for components only in one place, not in both.
So I have to divide Configuration to two: DatabaseConfiguration and ControllerConfiguration. Then it'll work