In Spring Boot 2.4 @EntityScan does not support property substitution

[tjuchniewicz]

@SpringBootApplication
@EntityScan("com.${test}")
public class EntityScanExampleApplication {

    public static void main(String[] args) {
        SpringApplication.run(EntityScanExampleApplication.class, args);
    }
}

test=value

For code above, in Spring Boot 2.4 entityscan.getPackageNames() returns com.${test}.
Worked in Spring Boot 2.3 and before.

Project to reproduce and check with 2.3: https://github.com/tjuchniewicz/spring-boot-entityscan-issue

[wilkinsona]

Thanks for the report. To my knowledge, we have never intentionally supported placeholders in @EntityScan. We certainly don't have a test for it anyway. The change in behaviour is due to the changes that we made for #22318. Moving away from reflection has meant that the constructor arguments no longer go through placeholder resolution.

Flagging for team attention to see if we want to reinstate the old behaviour and discuss how best to do that without regressing #22318.

[wilkinsona]

As @mbhave noted in #25415, @ComponentScan supports placeholders so we think it makes sense to reinstate @EntityScan's support for placeholders.