default on config pojo should behave the same if set in src/main/resources/application.yaml

[vsevel]

Description
Assuming the following config object:

@ConfigProperties(prefix = "greeting")
public class MyConfig {
    public String url;
    public String host;
}

and src/main/resources/application.yaml;

greeting:
  url: http://${greeting.host}
  host: myhost

Then the following test will pass:

@QuarkusTest
public class MyTestCase {

    @Inject
    MyConfig config;

    @Test
    public void test() {
        Assertions.assertEquals("http://myhost", config.url);
    }
}

However, if I move host=myhost as a default value, the test won't pass anymore:

greeting:
  url: http://${greeting.host}
  # host: myhost

and:

@ConfigProperties(prefix = "greeting")
public class MyConfig {
    public String url;
    @ConfigProperty(defaultValue = "myhost")
    public String host;
}

then I get the following error at startup:

Caused by: java.util.NoSuchElementException: SRCFG00011: Could not expand value greeting.host in property greeting.url

it is the same behavior if I put the default as the field init: public String host="myhost";

I believe that defaults should be picked up in the code, and applied as if the values were present in the src/main/resources/application.yaml.

[radcortez]

Related with eclipse/microprofile-config#475

[radcortez]

This can be achieved with @ConfigMapping. Check here: smallrye/smallrye-config@8f40839.

Quarkus @ConfigProperties is now deprecated, so our recommendation is to use @ConfigMapping.