require 'active_rdf' causes superclass mismatch for class DateTime

[Slava Kravchenko]

To make it brief, here's the code and backtrace extract:

irb(main):001:0> require 'rubygems'
=> true
irb(main):002:0> require 'active_rdf'
TypeError: superclass mismatch for class DateTime
 from /usr/lib/ruby/1.8/date/format.rb:1054
 from /usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:27:in `gem_original_require'
[...]
 from /usr/lib/ruby/gems/1.8/gems/activerdf-1.6.9/lib/active_rdf.rb:68
 from /usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:32:in `gem_original_require'
 from /usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:32:in `require'
 from (irb):2

I figure, it doesn't like this declaration in "objectmanager/literal.rb:42":
  class DateTime; include Literal; end
... which happens before "date/format.rb:1054":
  class DateTime < Date
because "literal.rb" is required before the first "require 'time'" (in "open-uri.rb").
I wonder why it seems never to have happened with the rest of developers. My configuration doesn't look special to me.

As a workaround, requiring "time" the first thing in your code solves this problem:

irb(main):001:0> require 'time'
=> true
irb(main):002:0> require 'rubygems'
=> true
irb(main):003:0> require 'active_rdf'
=> true

So there.

Here's the configuration:

activerdf - 1.6.9
activerdf_sparql - 1.3.5
rubygems - 1.0.1
ruby - 1.8.6
(OS: Debian Linux)

[Eyal Oren (ikbeneyal)]

I haven't seen this before, but I recently started seeing a 'constant already initialized' warning regarding date/format.rb, which is probably related to this bug. It must be something new in the date stdlib. I'll have a look at what's going on. What ruby version are you on?

[Slava Kravchenko (cordawyn)]

I wrote it at the bottom of my message:

activerdf - 1.6.9
activerdf_sparql - 1.3.5
rubygems - 1.0.1
ruby - 1.8.6
(OS: Debian Linux)

[Eyal Oren (ikbeneyal)]

Sorry, took me a while to realise, fixed now.
Probably something changed in the Ruby distribution recently, I had never seen this before.