accepts_nested_attributes_for and _destroy in one query

[artur79]

I'm using in my model accepts_nested_attributes_for. For specific scenerio only, when I try to add attachment_ids in first item and also I remove second item I receive mongo error.

[40]: Updating the path 'section9.significant_events.0.attachment_ids' would create a conflict at 'section9.significant_events' (on localhost:27017, legacy retry, attempt 1)

What is important attachment_ids in the first one must be new ones, If it's already persisted no error. So it looks like it tries to pass those attachment ids to the second item which is about to be deleted ? Dunno.

Here are the params passed to controller:

{"utf8"=>"✓",
 "_method"=>"patch",
 "authenticity_token"=>"xxxxx",
 "section9"=>
  {
   "significant_events_attributes"=>
    {"0"=>{"_destroy"=>"false", "description"=>"", "info_location"=>"", "attachment_ids"=>["", "62f4bd4fba962ee7ae1e96fd"], "id"=>"62f4b604ba962ee7ae1e96bd"},
     "1"=>{"_destroy"=>"true", "description"=>"", "info_location"=>"", "attachment_ids"=>[""], "id"=>"62f4b772ba962ee7ae1e96ca"}}
  },
 "commit"=>"Save",
 "section_map"=>"section9"}

and the relations are:

Section9
  embeds_many :significant_events
  accepts_nested_attributes_for :significant_events, allow_destroy: true

SignificantEvent
  has_and_belongs_to_many :attachments, class_name: 'Edoc'
  embedded_in :section9