Re: Import gem to Ruby 1.9

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Hi,

Tanaka Akira wrote:
>> Oh, I didn't think you maintain it.  But let's wait for what RubyGems
>> team think about the way you go.
> 
> RubyGems developers can choose to maintain or not.  I don't
> think there is a problem.

I think that RubyGems team possibly does not like this kind of logic
duplication.  Note that it's just a thought of mine.  I've heard nothing
about this from RubyGems team.

>> Definitely.  But it's a built-in logic of a ruby interpreter/Ruby
>> language.  We should be cautious.
> 
> Do you have a concrete problem?

Code duplication and independent maintainer as I wrote above.  My
concern will disappear once RubyGems team says they maintains it.

  require 'rubygems/gem_loadable_check'
  if Gem.gem_loadable?(feature)
    require 'rubygems'
  end
in prelude.rb is more better.

>> All spell are evil and spell for denying somethig are worse because it
>> generally don't work well and causes incomprehensible behavior.
> 
> I don't think it is evil or worse.  Do you have a concrete
> problem?

If it's not evil or worse, just let users use RUBYOPT as a charm to use
rubygems.  What's the difference?  But...

> Since it is intended to used as at first in RUBYOPT, I think
> it works.

Sorry, I don't understand this.

>> Sorry for confusing you.  You should know you can do anything at 'p "do
>> something good"' line because it's excerpted from your tiny rubygems
>> loader.  For example, replace;
>>   p "do something good"
>> with;
>>   raise unless require 'gemloader'
>>
>> This causes Name crash between rubygems and gemloader but it's not the
>> issue I want to point out as I wrote in the previous mail.
> 
> My tiny RubyGems loader and your above code doesn't conflict.
> 
> % cat fooloader.rb 
> module Kernel
>   alias foo_hooked_require require
> 
>   def require(feature)
>     begin
>       foo_hooked_require feature
>     rescue LoadError => e
>       raise unless require 'gemloader'
>       require feature
>     end
>   end
> end
> % RUBYOPT=-rfooloader ./ruby -e 'require "redcloth"; p RedCloth'
> RedCloth
> 
> The above ruby has my loader in prelude.rb.  RedCloth is
> installed as a gem.  RUBYOPT=-rfooloader doesn't cause a
> trobule: RedCloth can be required as usual, as fooloader
> expected.

Here's my try;

0% cat prelude.rb

# Mutex

class Mutex
  def synchronize
    self.lock
    begin
      yield
    ensure
      self.unlock
    end
  end
end

# Thread

class Thread
  MUTEX_FOR_THREAD_EXCLUSIVE = Mutex.new
  def self.exclusive
    MUTEX_FOR_THREAD_EXCLUSIVE.synchronize{
      yield
    }
  end
end

module Kernel
  alias original_require require
  def require(feature)
    original_require feature
  rescue LoadError
    if require 'rubygems'
      require feature
    else
      raise
    end
  end
end

0% cat foo.rb
module Kernel
  alias foo_hooked_require require

  def require(feature)
    begin
      foo_hooked_require feature
    rescue LoadError => e
      raise unless require 'gemloader'
      require feature
    end
  end
end

0% ls /usr/local/lib/ruby/gems/1.9/specifications
httpclient-2.1.2.gemspec

0% RUBYOPT=-rfoo ruby19 -e 'require "httpclient"'
/usr/local/lib/ruby/site_ruby/1.9/gemloader.rb:44: warning: already
initialized constant OPS
/usr/local/lib/ruby/site_ruby/1.9/gemloader.rb:94: warning: already
initialized constant Requirement
gemloader.rb intercepted rubygems loading
/usr/local/lib/ruby/site_ruby/1.9/rubygems/specification.rb:629:in
`method_missing': undefined method `<<' for {}:Hash (NoMethodError)
        from
/usr/local/lib/ruby/site_ruby/1.9/rubygems/specification.rb:629:in
`add_dependency'

OT: I removed module_function from prelude.rb to allow users to use
Kernel.require directly.

The last exception is the 'Name crash' I wrote in the previous mail.

> I know fooloader doesn't run in this case because my loader
> run.  However the result is identical: RedCloth is loaded.
> The two extensions doesn't conflicts because they does
> exactly same task.
>
> Please show working and conflicting example.

Now foo.rb loads gemloader.rb but think when I want to use one of a
custom loader (not existing now) I wrote in [ruby-core:12774].  Say
signed tarball loader.  It might have another repository which has
signed tarballs but RubyGems loads a gem instead of it, isn't it?

>> And those 2 behavior are not the point I wrote above.  Even if an user
>> want use another custom loader, your tiny rubygems loader loads rubygems
>> and a LoadError can activate gems.  As the result, the custom loader
>> cannot intercept the LoadError.  Am I misunderstand something?
> 
> I guess I don't understand the your point.
> 
> If an administrator installs a library as a gem, the library
> is expected to use.  If the library is not installed,
> LoadError is raised.
> 
> Do you think about that an administrator installs a library
> as a gem but an user doesn't want to use it?

Hmm.  I didn't think about it in detail but yes, it should be a
situation I'm wondering about.  For example, a Leopard user may want to
use mydevelgemloader.rb which only loads gems from ~/mydevel/gems.

Regards,
// NaHi

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