From: Sean Chittenden <sean@...>
Date: 2002-09-28T16:19:54+09:00
Subject: Re: Matz, if you're reading, please scan this email

> >>>>> "S" == Sean Chittenden <sean@chittenden.org> writes:
> 
> S> ./test/tests.rb -i 0
> 
>  Well, if I'm right the problem is in ruby_xml_parser_io_set()
> 
> 532       rxp->ctxt = ruby_xml_parser_context_new3();
> 533       data = (rx_io_data *)rxp->data;
> 534       data->io = io;
> 535       GetOpenFile(io, fptr);
> 536       rb_io_check_readable(fptr);
> 537       f = GetWriteFile(fptr);
> 538
> 539       Data_Get_Struct(rxp->ctxt, ruby_xml_parser_context, rxpc);
> 540       rxpc->ctxt = xmlCreateIOParserCtxt(NULL, NULL,
> 541                                          (xmlInputReadCallback) ctxtRead,
> 542                                          (xmlInputCloseCallback) ctxtClose,
> 543                                          f, XML_CHAR_ENCODING_NONE);
> 
>  When the object is garbage collected, ruby call
> 
> 89      void ruby_xml_parser_context_free(ruby_xml_parser_context *rxpc) {
> 90        if (rxpc->ctxt != NULL && rxpc->copy == RUBY_LIBXML_ORIG) {
> 91          xmlFreeParserCtxt(rxpc->ctxt);
> 92          ruby_xml_parser_count--;
> 93        }
> 94
> 95        if (ruby_xml_parser_count == 0)
> 96          xmlCleanupParser();
> 97
> 98        free(rxpc);
> 99      }
> 100
> 
>  xmlFreeParserCtxt() call ctxtClose() but the original object (data->io)
>  was previously closed by ruby : explicitely or the garbage collector has
>  found it before it try to release rxp->ctxt.
> 
>  The segfault is just because you call close() on a already closed IO.

:-/ You could be right, but, the IO context is created when reading
data from RAM, not from an actual IO socket.  I've created a simpler
use case:

http://lists.ruby-support.com/pipermail/ruby-developers/2002-September/000044.html

http://lists.ruby-support.com/pipermail/ruby-developers/2002-September/000045.html

That's a much simpler example.  -sc

-- 
Sean Chittenden