From: Erik Veenstra <google@...>
Date: 2005-02-05T06:20:15+09:00
Subject: Re: [BUG] RubyGems: "No such file to load -- rubygems/builder"

> > I added some debug information to the require method as
> > defined by RubyGems, because I didn't trust a message I got
> > ("No such file to load -- rubygems/builder").
> >
> > The problem occurs when require is invoked recursively. In
> > the situation that a LoadError is thrown some levels deep,
> > the file it complains about ("rubygems/builder") isn't the
> > file that raised the exception ("yaml", because it's the
> > first "9"-line). After installing "libyaml-ruby", I got one
> > step further: "zlib" is missing", and so on. But in all
> > situations, I got the same message ("No such file to load
> > -- rubygems/builder").
>
> This is a bug, and I'm not sure the best way to handle this
> -- but the real problem is the way that Debian-family Linuxes
> package Ruby.

I disagree. This example is a result of the strange Ruby
packages on Debian systems. That's true. But the same problem
can occur in other situations as well. The way the require
method of RubyGems catches the LoadError exception is the real
problem.

The solution is really easy... See below. You can use solution
B or C.

gegroet,
Erik V.

----------------------------------------------------------------

 $ cat a.rb
 class LoadError
 end

 module Kernel
   alias require__ require

   def require(path)
     require__ path
   rescue LoadError => e
     begin
       if false # No gem found.
       else
         #raise LoadError, "No such file to load -- #{path}"     # A
         #raise e                                                # B
         raise LoadError, e.message                              # C
       end
     end
   end
 end

 puts "A1"
 require "b"
 puts "A2"

 $ cat b.rb
 puts "B1"
 require "c"
 puts "B2"

 $ cat c.rb
 puts "C1"
 require "d"     # Doesn't exist.
 puts "C2"

 $ ruby a.rb
 A1
 B1
 C1
 a.rb:15:in `require': No such file to load -- d (LoadError)
         from a.rb:22

----------------------------------------------------------------