From: Paul Brannan <pbrannan@...>
Date: 2001-09-29T00:43:15+09:00
Subject: [ruby-talk:21806] Segfault with callcc

PragDave suggested that I post this to the ML, since it's an interesting
bug.  Perhaps some clever person out there knows what's going on.

It seems that when I try to use callcc, I keep segfaulting the Ruby
interpreter (1.6.5).  I have workarounds for my code (the one that's
worked the best so far is putting set_trace_proc proc{} at the top of my
script), but the bug keeps rearing its head unexpectedly.

The following code repeatably segfaults the Ruby interpreter:

class Foo
  def initialize(arr)
    cc1 = nil
    arr.each do |f|
      cc1 = callcc do |cc2|
        callcc do |cc1|
          cc2.call(cc1)
        end
        return
      end
    end
    # If I put a puts "foo" here, then this code doesn't crash.
    cc1.call(nil) unless not cc1
  end
end

a = b = [ 1 ]
Foo.new(a)
Foo.new(b)

There are some more examples in bug 185 at:
http://www.ruby-lang.org/cgi-bin/ruby-bugs/incoming?id=185;expression=callcc;user=guest

Any ideas what's going on?

Thanks,

Paul