Interrupt example from documentation not working

[citizen428]

Describe the bug

Executing the code from the Basic Usage of the Interrupt guide does not yield the expected result.

To Reproduce

Execute the code from the example:

require 'dry/effects'

class RunDivision
  include Dry::Effects::Handler.Interrupt(:division_by_zero, as: :catch_zero_division)

  def call
    success, answer = catch_zero_division do
      yield
    end

    if success
      answer
    else
      :error
    end
  end
end

class Divide
  include Dry::Effects.Interrupt(:division_by_zero)

  def call(dividend, divisor)
    if divisor.zero?
      division_by_zero
    else
      dividend / divisor
    end
  end
end

run = RunDivision.new
divide = Divide.new

app = -> a, b { run.() { divide.(a, b) } }

Expected behavior

Expected:

app.(10, 2) # => 5
app.(1, 0) # => :error

Got:

app.(10, 2) # => :error
app.(1, 0) # => nil

Your environment

• Affects my production application: NO
• Ruby version: 2.6.5
• Gem Version: 0.1.1
• OS: macOS 10.15.1

I'd look into it myself, but won't have time today.

[citizen428]

It seems like the first value in the return "tuple" is actually switched. If we treat the first return value as error instead of success everything works as expected:

require 'dry/effects'

class RunDivision
  include Dry::Effects::Handler.Interrupt(:division_by_zero, as: :catch_zero_division)

  def call
    error, answer = catch_zero_division do
      yield
    end

    if error
      :error
    else
      answer
    end
  end
end

class Divide
  include Dry::Effects.Interrupt(:division_by_zero)

  def call(dividend, divisor)
    if divisor.zero?
      division_by_zero
    else
      dividend / divisor
    end
  end
end

run = RunDivision.new
divide = Divide.new

app = -> a, b { run.() { divide.(a, b) } }

run = RunDivision.new
divide = Divide.new

app = -> a, b { run.() { divide.(a, b) } }
app.(10, 2) # => 5
app.(10, 2) # => :error

[flash-gordon]

Thanks!