linearize_thread_exceptions.rb

require 'thread'

def work(queue, &block)
  Thread.new do
    block.call(queue)
    queue << :done
  rescue StandardError => e
    queue << e
  end
end

def start
  workers = []
  queue = Queue.new

  # Linearize the work
  done_count = 0

  # Produce some work
  workers << work(queue) do |q|
    10.times do |i|
      sleep 1
      raise ArgumentError, 'error' if i == 5

      q << "thread 1: #{i}"
    end
  end

  workers << work(queue) do |q|
    20.times do |i|
      sleep 0.5
      q << "thread 2: #{i}"
    end
  end

  while (data = queue.pop)
    if data == :done
      done_count += 1
      break if done_count == workers.size
    elsif data.is_a?(Exception)
      # Linenarized error handling
      # optionally re-raise here
      p [:exception, data]
      raise data
    else
      puts data
    end
  end

  # rescue exceptions re-raised from threads here
rescue ArgumentError => e
  p [:rescued, e]
ensure
  puts 'byebug'
end

start