From: Brian Candler <B.Candler@...>
Date: 2003-07-27T06:23:48+09:00
Subject: Re: How to rescue any exception in 1.8?

On Sun, Jul 27, 2003 at 05:50:32AM +0900, Philip Mak wrote:
> This code will catch the exception in Ruby 1.6:
> 
> require 'timeout'
> begin
> 	raise TimeoutError
> rescue
> 	puts "Rescued!"
> end
> 
> But in Ruby 1.8, it will not catch the exception. I found out that if
> I do "rescue Exception" instead of just "rescue", it will work.
> 
> So, my question is, if I want to rescue any exception no matter what
> it is, do I have to start typing "rescue Exception" instead of
> "rescue"?

In general, you always did:

$ ruby16 -ve 'begin; require "flurble"; rescue; puts "ok"; end'
ruby 1.6.8 (2002-12-24) [i386-freebsd4.8]
-e:1:in `require': No such file to load -- flurble (LoadError)
        from -e:1

$ ruby16 -ve 'begin; require "flurble"; rescue Exception; puts "ok"; end'
ruby 1.6.8 (2002-12-24) [i386-freebsd4.8]
ok

'rescue' by itself is like 'rescue StandardError', I believe (which catches
StandardError and all its subclasses)

However it does look like timeout exceptions have changed from 1.6.8 to 1.8

1.6.8: raised TimeoutError, which was a subclass of StandardError
1.8.0: raises Timeout::Error, which is a subclass of Interrupt

However in 1.8.0 you can pass in an exception class, so you can do:

  require 'timeout'
  begin
    timeout(3, StandardError) do
      sleep 5
    end
  rescue
    puts "ok"
  end

Or, to make your code compatible with both versions, without trapping
absolutely every exception, you can do

  rescue StandardError, Interrupt

Cheers,

Brian.