From: "NAKAMURA, Hiroshi" <nakahiro@...>
Date: 2007-07-26T10:55:18+09:00
Subject: Re: Import gem to Ruby 1.9

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Hi,

Eric Hodel wrote:
>> This mail is for the topic '4. What $LOAD_PATH order should be?'

>>   # We replace Ruby's require with our own, which is capable of
>>   # loading gems on demand.
>>   #
>>   # When you call <tt>require 'x'</tt>, this is what happens:
>>   # * If the file can be loaded from the existing Ruby loadpath, it
>>   #   is.
>>   # * Otherwise, installed gems are searched for a file that matches.
>>   #   If it's found in gem 'y', that gem is activated (added to the
>>   #   loadpath).
>>   #
>>   # The normal <tt>require</tt> functionality of returning false if
>>   # that file has already been loaded is preserved.
> 
> The work of adding the gem's require_paths to $LOAD_PATH happens in
> Gem::activate.
> 
>> Custom 'require' at first try to load the specified feature name from;
>> [-I, ENV_RUBYLIB, SITELIBDIR, RUBYLIBDIR, .]
>> When it raises LoadError then add GEMs at the top of $LOAD_PATH and try
>> to load the feature from;
>> [GEMs, -I, ENV_RUBYLIB, SITELIBDIR, RUBYLIBDIR, .]
> 
> The behavior you describe is how 0.9.2 and previous worked.

Doh.  Sorry for bothering you.  I updated rubygems with
'gem update --system' and I confirmed that the behavior change you
explained.

> With GEMs before -I, the gem version can get loaded instead of the -I
> version.
> 
> With GEMs after -I, the -I version will always be preferred.

Agreed.

So the topic 4-2 should be;

  4. What $LOAD_PATH order should be?
    4-2. after requiring rubygems?
      [-I, ENV_RUBYLIB, GEMs, SITELIBDIR, RUBYLIBDIR, .]

As I wrote in the latest summary, this behavior should be up to RubyGems
team.  RubyGems team can control this behavior.

Then why I raised the topic to this thread?  Because I considered that
RubyGems may be enabled by default.

Eric,

  - you are thinking that $LOAD_PATH does not include GEMs dirs by
    default.
  - you think that 'hooking -r option' is all the requirement for
    ruby/1.9.1 to bundle RubyGems.

Right?  So the expected behavior is as follows?

% gem install httpclient
(done)
% ruby -rhttpclient -e 'p HTTPClient.get_content("http://localhost/")'
=> ruby: no such file to load -- httpclient (LoadError)
% ruby -rgem -rhttpclient -e '...'
=> (runs fine)

Of course we can direct users to use RUBYOPT=-rgem trick to hide this
detail though.

I think RubyGems should not be enabled by default but once after using
RubyGems, GEMs dir should be checked without any trick until the time I
run 'gem cleanup'.  Of course any other Ruby based new packaging system
can do the same thing.  Isn't it the behavior we expect to a packaging
system?

As you know, it requires rather complicated 'require-hook' feature to
ruby such as;

 - ruby checks "custom_require.rb" file in SITELIBDIR and load it before
   enabling any feature.

It may be too much for ruby/1.9.1.  'To use gem, run ruby with "-rgem"
always' can be accepted for the first step I think.

>>  Once an user found this answer, it gets easier to track down a loader
>> problem in soap4r-ml.  The rest I want to know is where 'gem "soap4r"'
>> should be added in RoR environment... (I've not yet been a RoR user.)
> 
> config/environment.rb is the correct place in RoR.

Thanks!  It much help soap4r users.

// NaHi

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