[ruby-core:26226] Re: Config.datadir in 1.9.1

On Thu, Oct 22, 2009 at 04:55, Yugui <[e-mail]> wrote:

> 2009/10/21 Nikolai Weibull <[e-mail]>:

>> In 1.8.6., Config.datadir('package') would give you the gem-relative
>> data directory for a gem.  In 1.9.1, Config doesn’t seem to even be
>> loaded at startup.  What happened?  What am I supposed to use instead?
>>  Even if you get Config loaded it still won’t work, as the gem’s paths
>> are already added to $LOAD_PATH, so Rubygems won’t load the
>> specification and thus Gem.datadir('package') will give a nil result.

> First, ::Config is deprecated. You should use RbConfig instead.
> ::Config is an alias of RbConfig for compatibility to < 1.8.
>
> Second, RbConfig is a bundled library but not a core library. So it is
> not loaded by default.
> I think it has been loaded by RubyGems when you use RubyGems.
>
> Third, RbConfig.datadir(pkg) is a part of RubyGems but not a part of RbConfig.
>
> So you should write like this:
>
>  require 'rbconfig'
>  require 'rbconfig/datadir'
>
>  RbConfig.datadir("blahblahblah")
>
> This works fine for both 1.8 and 1.9.

Well, actually it doesn’t work.  I mean, yes, the function is there,
but the problem is that it doesn’t return the correct path.  Let me
clear this up a bit.  Assume that expectations-1.2.1 is installed for
both 1.8 and 1.9.1.

In 1.8.6, with RUBYOPT="-rubygems", I could simply start up irb and
the following would happen:

% irb
irb(main):001:0> require 'expectations'
=> true
irb(main):002:0> Config.datadir('expectations')
=> "C:/Ruby18/lib/ruby/gems/1.8/gems/expectations-1.2.1/data/expectations"

but on 1.9.1 that isn’t as straightforward.  Fine, we’ll do the
following instead:

% irb
irb(main):001:0> require 'expectations'
=> true
irb(main):002:0> require 'rbconfig'
=> true
irb(main):003:0> require 'rbconfig/datadir'
=> true
irb(main):004:0> RbConfig.datadir('expectations')
=> "C:/Ruby19/share/expectations"

OK, so Rubygems isn’t loaded automatically and can thus not override
RbConfig.datadir.  What we need to do seems to be

% irb
irb(main):001:0> require 'expectations'
=> true
irb(main):002:0> Gem.datadir('expectations')
=> nil
irb(main):003:0> gem 'expectations'
=> true
irb(main):004:0> RbConfig.datadir('expectations')
=> "C:/Ruby19/lib/ruby/gems/1.9.1/gems/expectations-1.2.1/data/expectations"

and that, my friends, is insane.  The Gem.datadir('expectations')
seems to be needed to get the gem 'expectations' to actually do
anything (it returns false if the Gem.datadir('expectations') doesn’t
appear before it).  I’m guessing that that line loads up Rubygems,
because a require 'rubygems' sure doesn’t.

So instead of Rubygems being transparently integrated into Ruby 1.9.1,
what I’ve got now is an incredible mess where I need to force Rubygems
to rear its ugly head all over the place.