AggregateRoot::AutoConflictResolution

[paneq]

Idea described here: https://github.com/RailsEventStore/aggregate_root/issues/8#issuecomment-325655544

This is a separate issue because it's a different idea than just handling concurrency properly.

[paneq]

BTW

module AutoConflictResolution
  def store(stream_name = loaded_from_stream_name, event_store: default_event_store)
    super
  rescue
    unpublished_events = unpublished_events()
    tried_version = version
    self.load(stream_name, event_store: event_store)
    published_events = loaded_events[tried_version+1..version]
    if not_conflicting(unpublished_events, published_events)
      @unpublished_events = unpublished_events
      store(stream_name: stream_name, event_store: event_store)
    end
  end
end

class OrderWithNonConflictingStore < Order
  include AutoConflictResolution
  private

  def not_conflicting(unpublished_events, published_events)
    true
  end
end

This part :

published_events = loaded_events[tried_version+1..version]

could be optimized better to use RES to read all events on position >= tried_version+1 instead of reading all events again and selecting from array those conflicting ones.

But that's just a performance optimization.

[mostlyobvious]

Duplicate #140