Add class name to missing attribute error

lib/dry/struct.rb

@@ -145,7 +145,9 @@ def initialize(attributes)
  # rom_n_roda[:title] #=> 'Web Development with ROM and Roda'
  # rom_n_roda[:subtitle] #=> nil
  def [](name)
- @attributes.fetch(name) { raise MissingAttributeError, name }
+ @attributes.fetch(name) do
+ raise MissingAttributeError.new(attribute: name, klass: self.class)
+ end
  end
 
  # Converts the {Dry::Struct} to a hash with keys representing

lib/dry/struct/errors.rb

@@ -16,8 +16,8 @@ def initialize(key)
 
  # Raised when a struct doesn't have an attribute
  class MissingAttributeError < ::KeyError
- def initialize(key)
- super("Missing attribute: #{key.inspect}")
+ def initialize(attribute:, klass:)
+ super("Missing attribute: #{attribute.inspect} on #{klass}")
  end
  end
 

spec/integration/struct_spec.rb

@@ -353,7 +353,7 @@ class Task < Dry::Struct
 
  expect { value[:name] }
  .to raise_error(Dry::Struct::MissingAttributeError)
- .with_message("Missing attribute: :name")
+ .with_message("Missing attribute: :name on Test::Task")
  end
 
  describe "protected methods" do