Configuration values that are stored as maps in configuration files are merged, not overwritten.

[sstone]

Features are represented as a map in our configuration files, which means that the corresponding configuration object defined in application.conf does not overwrite the "base" definition found in reference.conf, as it would if it was a string or number, but is merged with it (see https://github.com/lightbend/config/blob/c17d58e09af11f9e2a9ddae2eccca18f5f0f01f6/HOCON.md#duplicate-keys-and-object-merging).

With the following configuration files:

reference.conf:
  features {
    initial_routing_sync = optional
    option_data_loss_protect = optional
    gossip_queries = optional
    gossip_queries_ex = optional
    var_onion_optin = optional
  }

application.conf:
  features {
    option_data_loss_protect = mandatory
    var_onion_optin = optional
    payment_secret = optional
    basic_mpp = optional
  }

The final configuration, as read by the application, will be equivalent to:

  features {
    initial_routing_sync = optional
    option_data_loss_protect = mandatory
    gossip_queries = optional
    gossip_queries_ex = optional
    var_onion_optin = optional
    payment_secret = optional
    basic_mpp = optional
  }

There are several potential fixes:

• configuration keys that are represented by maps could be removed from eclair-core's reference.conf file, so there's nothing to merge with.
• a null value could be inserted in application,.conf to discard values defined in reference.conf:

application.conf:

  features : null
  features {
    option_data_loss_protect = mandatory
    var_onion_optin = optional
    payment_secret = optional
    basic_mpp = optional
  }

• or we could use an another representation for map-like fields such as Features

[t-bast]

Fixed by #1435