Exception doesn't propagete

[userlocalhost]

I want to catch exception which is occurred in handler of Listen like this.

begin
  listen = Listen.to '.' do |mod, add, rem|
    raise
  end
  listen.start

  ### some processing
  sleep

rescue Exception => e
  ### Couldn't catch exception
end

When I execute this and modify a file in the current directory, an exception message is put out to STDERR.
But I couldn't catch exception.

Please tell me how I can do it.

[e2]

The block's code is called from a different thread, so you'll need a Queue to collect the exception and raise it in the main thread.

What you probably want is this (it should work - I haven't checked):

require 'thread'

begin
  exceptions = Queue.new
  listen = Listen.to '.' do |mod, add, rem|
    begin
      raise
    rescue Exception => e
      exceptions << e
      listen.stop # to prevent more events/callbacks
      Thread.main.wakeup # to interrupt the 'sleep' below
    end
  end

  listen.start

  ### some processing

  sleep # will be interrupted by `wakeup` above

  raise exceptions.pop unless exceptions.empty?

rescue Exception => e
  # handling
end

[userlocalhost]

Thank you for your reply.
I could catch an exception on the main thread as below.

begin
  exceptions = Queue.new
  listen = Listen.to '.' do |mod, add, rem|
    begin
      raise
    rescue Exception => e
      exceptions << e
      Thread.main.wakeup # to interrupt the 'sleep' below
    end
  end

  listen.start

  ### some processing

  sleep # will be interrupted by  above

  # calling this in the block of listener causes hangup in my environment
  listen.stop

  raise exceptions.pop unless exceptions.empty?
rescue Exception => e
  # handling
end

The problem was settled by your favor. Thank you!

[github0013]

This is an old issue, but I thought this is worth mentioning.

# need an exception not extended from StandardError
# otherwise the exception will be rescued inside Listen
class StopError < Interrupt; end

begin
  previous = Thread.abort_on_exception
  # https://ruby-doc.org/core-2.6.3/Thread.html#method-c-abort_on_exception-3D
  Thread.abort_on_exception = true

  dir = __dir__
  puts "*"*20
  puts "add some file @ #{File.expand_path dir}"
  puts "*"*20
  Listen.to(dir) do |modified, added, removed|
    raise StopError
  end.start

  sleep

rescue StopError => ex
  puts "rescued"
ensure
  Thread.abort_on_exception = previous
end