Do notation doesn't work for children classes about dry-monads

[flash-gordon]

@korolvs oh, you're right and it's rather unexpected. I ditched inheritance completely that's why I haven't come across the issue. I'll fix it tomorrow since it'll require some testing before being sure it's fixed properly

[lcolombini]

Hi,
I have the similar error on github actions :LocalJumpError: no block given (yield)
When i run the CI on github actions, the keyword 'yield' by Dry monads not works. WHen I run locally all tests are ok. What is the reason?

[flash-gordon]

It doesn't work for subclasses because .for is not aware of them. If you want this, use the inherited hook in the way described in the link you posted. Another solution is to go with the fully automated version of Do, this will do the trick:

include Dry::Monads::Do

^it will wrap all the methods defined after this line, including subclasses

[slavadev]

Thank you for the answer!
Did I understand the fully automated version correctly?

class BaseCommand
  include Dry::Monads::Result::Mixin
  include Dry::Monads::Do
  
  def validate
    Success(:ok)
  end
end

class CreateCommand < BaseCommand
  def call
    yield validate
  end
end

Doesn't work for me as well, I'll use another methods

[jdwolk]

Just a PSA for people who still get LocalJumpError: no block given (yield) despite using include Dry::Monads::Do:

Double-check that your base class isn't defining self.inherited somewhere. I had code like this:

class MyBaseClass
  include Dry::Monads[:result]
  include Dry::Monads::Do

  def.self.inherited(subclass)
    ...
  end
end

class Subclass < MyBaseClass
  def call
    yield foobar
  end
end

I was getting this issue until I found out Dry::Monads::Do::All is doing some metaprogramming with self.inherited: https://github.com/dry-rb/dry-monads/blob/master/lib/dry/monads/do/all.rb#L70

The fix was to call super in self.inherited on the base class, i.e.:

class MyBaseClass
  include Dry::Monads[:result]
  include Dry::Monads::Do

  def.self.inherited(subclass)
    super(subclass)
    ...
  end
end

class Subclass < MyBaseClass
  def call
    yield foobar
  end
end

[flash-gordon]

@lcolombini pls ask questions on our forum (see contributing.md for the link). Please also attach example code that doesn't work, at least essential parts. Otherwise, I can't what's wrong.

[lcolombini]

@flash-gordon the sample is a classic dry-monads construct:

`def call
      value = yield get_value_func
  end
`

When I ran CI on GitHub, the error was LocalJumpError: no block given (yield), but I undestand the problem I the library Dry-Monads v1.4 in latest Ubuntu.
I'm developing on Mac OS and I don't have errors. I switched on Ubuntu machine for a trial and I replicated the issue. I solved back to v.1.3.5

[EduardoSimon]

I am getting the same result. In my case I am using docker, so we cannot update the library.

Ruby version:

• ruby 2.7.3p183 (2021-04-05 revision 6847ee089d) [x86_64-linux-musl]

[kleinjm]

I ran into this when my code was inside an concerning(:name) do block. Definitely unexpected behavior but not sure if there's an easy fix