Duplicate `@ConfigurationProperties` in two different profile

Why can't I define two bean with the same configurationProperties prefix? Code below throws the following error:

Duplicate `@ConfigurationProperties` definition for prefix 'config'

I know it is the same but for two different profile. Is there any other way I may
do it ?

@Profile("MyProfile")
@Bean(initMethod = "init", name = "MyConfig")
@ConfigurationProperties(prefix = "config")
public MyConfig config() {
    MyConfig config = new MyConfig();
    return config;
}

@Profile("!MyProfile")
@Bean(initMethod = "anotherInit", name = "MyConfig")
@ConfigurationProperties(prefix = "config")
public MyConfig myConfig() {
    MyConfig config = new MyConfig();
    return config;
}

UPDATE:

> [ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.8.1:compile (default-compile) on project my-app: Compilation failure:
Compilation failure:

> [ERROR] ...MyConfig.java:[21,22] Duplicate @ConfigurationProperties definition for prefix 'config'

Like mentioned in your comment, this compile time error is introduced by annotation processor - spring-boot-configuration-processor.

How it decides whether duplicate configuration properties exists ?

It decides on 2 things -

1. Property Prefix
2. Configuration class name / Return Type of the method

Notice that Spring profile name isn't part of finding duplicates. So, both configurations are similar. This is causing the compile time error.

Solution

Either you raise a bug with the spring api or do something that makes those 2 properties different. One way and I think the only way is to create a new configuration class that extends original one. This will ensure that they are not treated as duplicates.

class SomeOtherProfileConfig extends MyConfig {
}

@Profile("MyProfile")
@Bean(initMethod = "init", name = "MyConfig")
@ConfigurationProperties(prefix = "config")
public MyConfig config() {
    MyConfig config = new MyConfig();
    return config;
}

@Profile("!MyProfile")
@Bean(initMethod = "anotherInit", name = "MyConfig")
@ConfigurationProperties(prefix = "config")
public SomeOtherProfileConfig myConfig() {
    SomeOtherProfileConfig config = new SomeOtherProfileConfig();
    return config;
}

You can declare a single class for the @ConfigurationProperties, the properties will be picked from the active profile's properties file. Then, you can use the properties in different beans with @EnableConfigurationProperties