Trailblazer Operation undefined method `call' for nil:NilClass

Question

I have a simple Trailblazer Operation as follow:

class User::Delete < Trailblazer::Operation
  extend Contract::DSL

  contract 'params' do
    property :token

    validates :token, presence: true
  end

  step    Contract::Validate(name: 'params'), before: 'operation.new'
  success :kill_zombie

  def kill_zombie(options, params:, **)
    options['killed'] = true
  end

end

When I run the operation under the rails console, that's the output:

irb(main):003:0> User::Delete.()
NoMethodError: undefined method `call' for nil:NilClass
    from (irb):3

If I remove the Contract line:

class User::Delete < Trailblazer::Operation
  extend Contract::DSL

  contract 'params' do
    property :token

    validates :token, presence: true
  end

  success :kill_zombie

  def kill_zombie(options, params:, **)
    options['killed'] = true
  end

end

It works as expected:

irb(main):005:0> User::Delete.()
=> <Result:true <Skill {"killed"=>true} {"params"=>{}} {"pipetree"=>[>operation.new,>kill_zombie], "contract.params.class"=>#<Class:0x0000000003e54e50>}> >
irb(main):006:0>

Any thoughts?

score 2 · Accepted Answer · answered Dec 29 '17 at 09:25

2

You need a Contract::Build before Contract::Validate when using a Reform contract. With a Dry schema, the build step isn't needed.

answered Dec 29 '17 at 09:25

apotonick

520
2
9

Can you provide a snippet code (even if it's redundant from the documentation) ? – Jeremie Ges Dec 29 '17 at 10:51

score 1 · Answer 2 · answered Dec 29 '17 at 08:55

1

I would dig deep in the documentation http://trailblazer.to/gems/operation/2.0/contract.html

The message means that you are trying to call a method on a nil object.

The Object is User::Delete and the method is .()

User::Delete.()

User::Delete could be undefined because it is not passing your validation?

step    Contract::Validate(name: 'params'), before: 'operation.new'

Just posting to give you some input, I don't have a solution. I would inspect User::Delete before calling the method.

User::Delete will be nil and you need to change the validation or make sure that object is correctly instantiated.

answered Dec 29 '17 at 08:55

Fabrizio Bertoglio

5,890
4
16
57

Just dug in the documentation, I feel like I have to use Dry::Validation for linear validations – Jeremie Ges Dec 29 '17 at 09:04
@JeremieGes yes something like `(Dry::Validation.Schema do required(:id).filled end)` from http://trailblazer.to/gems/operation/2.0/contract.html#dry-schema – Fabrizio Bertoglio Dec 29 '17 at 09:09

Trailblazer Operation undefined method `call' for nil:NilClass

2 Answers2