Creating an item with a nil scope should not add it to the list

[matteomelani]

Thank for this great gem.
I have a quesiton/issue related to default scope. Thanks for any help.

class NewContent < ActiveRecord::Base
  acts_as_list add_new_at: :top, scope: :collection
end

n = NewContent.create
puts n.position 
   => 1

But collection_id is null.

This is creates a huge performance problem because every time I create a NewContent it is going to add to the list of item with collection_id set to null.

[matteomelani]

Overwriting the scope_condition seems to work

def scope_condition
    if collection_id.present?
      "collection_id = #{collection_id}"
    else
      "id = -1"
    end
 end

[swanandp]

Hi @matteomelani ,

acts_as_list does not maintain the value for scope, it'll only look up the scope while re-ordering, inserting etc.

The correct way would be:

n = NewContent.new(collection: collection_id)
n.save

[randallb]

@swanandp I think you're misunderstanding the issue.

If I don't want to add an item to a collection, I definitely don't want to set the position column, so that I don't incur the performance penalty of looking up the entire list of nil items.

Right now I'm trying to hack around this when I discovered this issue.

http://stackoverflow.com/questions/22334899/conditionally-activate-acts-on-list-when-field-is-defined

[johnnyiller]

I just ran into this problem... Huge performance issue when you are first creating items then optionally adding them to a list later on... I guess the solution is to add them to some sort of temp list or something, but that seems a bit silly. Really there should be a way to only update the list if the scope variables are set...

[thefron]

I'm facing this issue too.
I need something like complete disable of ordering when scope id is nil.

[brendon]

This doesn't sound like a bad idea. Would one of you like to take a stab at implementing it and creating a PR?

Right now I guess nil is as valid a scope as say 1 or whatever your custom scope is, so acts_as_list is using that to group your items. We're assuming you order all your things.

If I hear nothing after a few weeks I'll close this until someone is happy to work on it.

[brendon]

Closing due to inactivity. @thefron, @johnnyiller, @randallb, @matteomelani feel free to contribute a PR to solve this issue.

[mathportillo]

sorry for commenting on a closed issue,
but should this be easier to achieve now that there is acts_as_list_no_update ?

[brendon]

Yes, that's definitely the case, but that'd be implemented on your end. If you want to look at a solution regarding a scope that evaluates to nil then certainly have a go :)

[phikes]

Recently stumbled upon this as well. The API of the method is now slightly different, it seems. This works for us as of today:

  def scope_condition
    if list_id.present?
      { list_id: list_id }
    else
      { id: -1 }
    end
  end

[smlparry]

@phikes solution works for me, but yeah, this should probably be part of the library

Was having an issue where all records with a nil scope were getting their updated_at being updated :/