Unique comments repeated in MapProperty, ListProperty, ...

[ljacqu]

Reported by Wector11211: if a comment is set on a bean that's used in a MapProperty, the comment is repeated even if it's defined to be unique:

public class ServerSettingHolder implements SettingsHolder {

    public static final Property<Map<String, ServerCollection>> SERVERS =
        new MapProperty<>("", 
          Map.of("foo", new ServerCollection(), "bar", new ServerCollection()),
          BeanPropertyType.of(ServerCollection.class));

}


public class ServerCollection {

    @Comment("Comment that is present on all instances")
    private List<String> servers = new ArrayList<>();

    public List<String> getServers() {
        return servers;
    }

    public void setServers(List<String> servers) {
        this.servers = servers;
    }
}

Problem

The mapper keeps a set of unique comments it's already used. The problem is when a bean type is used multiple times within the same property, it goes beyond the boundaries of the bean type. This not only affects MapProperty but any other collection properties where a bean property is used as type.

Solving this is a little tricky—I don't want to keep any global state, but there needs to be some mechanism to pass in a bit more state across multiple #toExportValue calls...