From: Bill Lear <rael@...>
Date: 2008-05-01T23:18:00+09:00
Subject: Ruby exceptions and YAML

I'm confused by how YAML seems to not work with ruby exceptions.  I
tried searching in vain, thus this quick post.

I would like to serialize and deserialize exception objects, but when I
deserialize a serialized exception, it does not appear to be able to
access the original message, even thought the YAML output seems to have
it.  I would think that for any ruby object 'obj', the following should
hold:

obj == YAML::load(YAML::dump(obj))

but this seems to not be the case.  Here is a short test script
illustrating the issue:

require 'cgi'
require 'yaml'

begin
        raise "Ain't got no mojo"
rescue => ex
        if YAML::load(YAML::dump(ex)) != ex
                puts "NOT EQUAL"
        end

        puts "class=#{ex.class} message=#{ex.message}"
        puts ex.message

        dumped = YAML::dump(ex)
        puts dumped

        loaded = YAML::load(dumped)
        puts "class=#{loaded.class} message=#{loaded.message}"

        dumped_2 = YAML::dump(loaded)
        puts dumped_2

        loaded_2 = YAML::load(dumped_2)
        puts "class=#{loaded_2.class} message=#{loaded_2.message}"
end

and here is a run:

% ruby --version
ruby 1.8.6 (2008-03-03 patchlevel 114) [x86_64-linux]
% ruby test_exception_dump.rb
NOT EQUAL
class=RuntimeError message=Ain't got no mojo
Ain't got no mojo
--- !ruby/exception:RuntimeError
message: Ain't got no mojo
class=RuntimeError message=RuntimeError
--- !ruby/exception:RuntimeError
message: RuntimeError
mesg: Ain't got no mojo
class=RuntimeError message=RuntimeError

Have I misunderstood something here, or is there something fundamentally
wrong with ruby YAML?


Bill
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