This fixes #121

[zeitnot]

In mongoid4 ::Mongoid.const_defined? :Observer always returns true. So we should check it by mongoid natural version number. BTW this fix works for me.

Another workaround is here but I did not test it.

[dblock]

We have CI running here against all versions of Mongoid, and with version 4 Mongoid::Observer is most definitely deprecated. There're dozens of other gems that do it the same way, including mongoid-slug for example.

Are you using another gem that (re)introduces the observer backward compatibility?

I think comparing with a string is extremely brittle, I'd be probably OK with something that introduces a proper version parser here from a thirdparty gem.

[zeitnot]

These are my mongoid related gems.

gem 'mongoid', '~> 4.0.0'  
gem 'mongoid-observers', '~> 0.1.1'
gem 'mongoid_paranoia', github: 'simi/mongoid_paranoia'
gem 'mongoid_search', '~> 0.3.2'
gem 'mongoid_token', github: 'thetron/mongoid_token', branch: 'update/mongoid-4'
gem 'mongoid-history', github: 'zeitnot/mongoid-history'

I did consider using this gem as version comparing tool but did not pollute gem file. :)

[dblock]

Well, likely that mongoid-observers is where this comes from :) As mentioned above I would be ok with a reliable version parser to verify which version of mongoid it is.

[zeitnot]

Yes, mongoid-observers is the main guilty :)

[zeitnot]

@dblock I do not have any idea why this commit crashes on rubinius. I did not find anything on google. Will you merge this one or do you know anything about this crash? Thanks.

[johnnyshields]

The Rubinius failures look related to infrastructure (bundler not running properly), so probably not introduced by this commit. Travis will probably succeed if we run it again.

[dblock]

This has been merged via 7ab06f4.

[dblock]

I had to undo this, opened #126, the rbx failure is in blockenspiel, and will continue breaking the build until that's fixed - dazuma/blockenspiel#13.