From: "Jörg W Mittag" <JoergWMittag+Ruby@...>
Date: 2011-01-01T23:45:21+09:00
Subject: Re: update_rubygems problem

Luis Lavena wrote:
> On Dec 31 2010, 11:42 pm, Jörg W Mittag <JoergWMittag
> +R...@GoogleMail.Com> wrote:
>> Jakub Arnold wrote:
>>> RubyGems 1.4.0 doesn't work on Ruby 1.9.x, yet.
>> Shouldn't it have
>>
>>     required_ruby_version = '< 1.9'
>>
>> set in rubygems-update.gemspec, then?
>>
>> Or have I fundamentally misunderstood what that's for? (Quite likely.)
> Something like that.
> 
> The problem is not RubyGems, but Ruby's own "gem-prelude"
> functionality.
> 
> The version of RubyGems that is bundled with Ruby is not meant to be
> updated by the normal mechanism.

The documentation says otherwise:

    # gem help update
    Usage: gem update GEMNAME [GEMNAME ...] [options]

      Options:
            --system                     Update the RubyGems system software

If the 'gem update --system' functionality isn't meant to be used,
then why is it even there, and documented? Shouldn't it be removed? At
least, that's what the RubyGems maintainers told the Debian
maintainers, IIRC.

>  Until that is sorted *in Ruby*, we can't do anything.

I thought the whole point of putting stuff *into* Ruby was to *avoid*
version conflicts like this? I remember the developers of RubyOPAL
warning that putting RubyGems into Ruby would make it impossible to
develop better package management systems; I bet they never thought
that one of those better package management systems would be RubyGems
*itself* (-:

I guess the best part of this situation is that it will hopefully shut
up the "cram everything into Ruby" proponents and strengthen the
arguments of the proponents of *unbundling*.

> We could have limited the gem update version matching, but then it
> will raise questions like "I'm using Ruby 1.9.x and I'm not getting
> RubyGems 1.4.0 when doing gem update --system"
> 
> So, the issue will be similar: inability to update RubyGems, either by
> the gem requirement or by Ruby's own issues.

But the *message* won't.

With the version restriction in the gemspec, you would get something
like

    # gem update --system
    Updating RubyGems
    Updating rubygems-update
    ERROR:  Error installing rubygems-update:
            rubygems-update requires Ruby version < 1.9.

Whereas right now, you actually get this:

    # gem update --system
    <internal:lib/rubygems/custom_require>:29: warning: loading in progress, circular require considered harmful - C:/Ruby/lib/ruby/1.9.1/rubygems.rb
            from C:/Ruby/bin/gem:8:in `<main>'
            from <internal:lib/rubygems/custom_require>:29:in `require'
            from <internal:lib/rubygems/custom_require>:29:in `require'
            from C:/Ruby/lib/ruby/1.9.1/rubygems.rb:1136:in `<top (required)>'
            from C:/Ruby/lib/ruby/1.9.1/rubygems.rb:968:in `load_plugins'
            from C:/Ruby/lib/ruby/1.9.1/rubygems.rb:968:in `each'
            from C:/Ruby/lib/ruby/1.9.1/rubygems.rb:976:in `block in load_plugins'
            from C:/Ruby/lib/ruby/1.9.1/rubygems.rb:976:in `load'
            from C:/Ruby/lib/ruby/gems/1.9.1/gems/yard-0.6.4/lib/rubygems_plugin.rb:2:in `<top (required)>'
            from <internal:lib/rubygems/custom_require>:29:in `require'
            from <internal:lib/rubygems/custom_require>:29:in `require'
            from C:/Ruby/lib/ruby/1.9.1/rubygems/doc_manager.rb:8:in `<top (required)>'
            from <internal:lib/rubygems/custom_require>:29:in `require'
            from <internal:lib/rubygems/custom_require>:29:in `require'
    Updating RubyGems
    Updating rubygems-update
    Temporarily enhancing PATH to include DevKit...
    Successfully installed rubygems-update-1.4.1
    Updating RubyGems to 1.4.1
    Installing RubyGems 1.4.1
    C:/Ruby/lib/ruby/gems/1.9.1/gems/rubygems-update-1.4.1/lib/rubygems/source_index.rb:62:in `installed_spec_directories': undefined method `path' for Gem:Module (NoMethodError)
            from C:/Ruby/lib/ruby/gems/1.9.1/gems/rubygems-update-1.4.1/lib/rubygems/source_index.rb:52:in `from_installed_gems'
            from C:/Ruby/lib/ruby/gems/1.9.1/gems/rubygems-update-1.4.1/lib/rubygems.rb:914:in `source_index'
            from C:/Ruby/lib/ruby/gems/1.9.1/gems/rubygems-update-1.4.1/lib/rubygems/gem_path_searcher.rb:98:in `init_gemspecs'
            from C:/Ruby/lib/ruby/gems/1.9.1/gems/rubygems-update-1.4.1/lib/rubygems/gem_path_searcher.rb:13:in `initialize'
            from C:/Ruby/lib/ruby/gems/1.9.1/gems/rubygems-update-1.4.1/lib/rubygems.rb:873:in `new'
            from C:/Ruby/lib/ruby/gems/1.9.1/gems/rubygems-update-1.4.1/lib/rubygems.rb:873:in `searcher'
            from C:/Ruby/lib/ruby/gems/1.9.1/gems/rubygems-update-1.4.1/lib/rubygems.rb:495:in `find_files'
            from C:/Ruby/lib/ruby/gems/1.9.1/gems/rubygems-update-1.4.1/lib/rubygems.rb:1034:in `load_plugins'
            from C:/Ruby/lib/ruby/gems/1.9.1/gems/rubygems-update-1.4.1/lib/rubygems/gem_runner.rb:84:in `<top (required)>'
            from <internal:lib/rubygems/custom_require>:29:in `require'
            from <internal:lib/rubygems/custom_require>:29:in `require'
            from setup.rb:25:in `<main>'
    RubyGems system software updated

You actually get a *success* message. You also get a NoMethodError
exception, of course, but that exception is accompanied by a warning,
which looks *exactly like* an exception, and which you learned to
automatically mentally filter out, since you *always* get tons of
warnings from Ruby (circular require), from RubyGems (something about
instance variable @prerelease not initialized and Win32API being
deprecated) and literally tens of thousands of warnings from YARD (two
warnings about two different uninitialized instance variables and an
overlapping range in a character class in a Regexp for every pass of
every visitor over every AST node of every file of every Gem).

jwm