From: Gregory Brown <gregory.t.brown@...>
Date: 2007-07-17T04:05:11+09:00
Subject: Re: Odd requirement behavior between two environments

On 7/16/07, Ian Whitney <iwhitney@ssa-i.org> wrote:

> Ok, so that looks good. I can require the gem & then IRB knows what
> ActiveRecord is. Great.
>
> New development machine where this doesn't work
>     Ruby 1.8.6
>     Gems 0.9.4
>     ActiveRecord gem installed 1.15.3
>
> Results of IRB session on the new development machine
>
> irb(main):001:0> require 'rubygems'
> => true
> irb(main):002:0> gem 'activerecord'
> => true
> irb(main):003:0> ActiveRecord
> NameError: uninitialized constant ActiveRecord
>         from (irb):3
>
> So, something is up. In line 2 I'm using the command newer command 'gem'
> instead of the depreciated 'require_gem'. But I get the same result even if
> I use the depreciated command.
>
> Any ideas? Something I forgot to install on this new machine? Or some weird
> configuration change I made on the old machine that I didn't copy over.

require_gem / gem are not the same as require.  They're meant for
locking gems to specific versions or making sure they exist, not
loading libraries, e.g.

gem "ruport", "=1.0.1"

Also, with that in mind note that gem names don't always coincide with
library names, so you actually will need to do this:

require "rubygems"
require "active_record"

In earlier versions of RubyGems, it was possible for the require_gem
command to autoload libraries, this is no longer the case.

Hope that helps...

-greg