[ruby-core:40247] [Ruby 1.9 - Bug #4969] Subtle issue with require

Issue #4969 has been updated by Thomas Sawyer.


I've gone ahead and released the *loadable* gem. You can read about it at http://github.com/rubyworks/loadable. I know there has been some talk here about creating a more flexible load path. loadable works by adding load hook objects to the $LOADERS global variable. Load hooks are any object that responds to #call, which loads/requires the file, and #each, that iterates over all loadable files. It also extends #require and #load to accept an options hash to allow loader configurations.

The Ruby Loader that it comes with can be used to isolate loading from Ruby's standard library. But this issue (#4969) prevents it form fully working.

So, what's the word on this?

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Bug #4969: Subtle issue with require
http://redmine.ruby-lang.org/issues/4969

Author: Thomas Sawyer
Status: Feedback
Priority: Normal
Assignee: 
Category: 
Target version: 
ruby -v: -


If I have a library with same name as Ruby standard library in load path (as an example):

  lib/abbrev.rb

There is conflict with loading. Ok, I work around:

  require 'rbconfig'

  # Notice that rubylibdir takes precendence.
  LOCATIONS = ::RbConfig::CONFIG.values_at(
    'rubylibdir', 'archdir', 'sitelibdir', 'sitearchdir'
  )

  #
  def require_ruby(file)
    LOCATIONS.each do |loadpath|
      if path = lib_find(loadpath, file)
        return path
      end
    end

    raise LoadError, "no such file to load -- #{fname}"
  end

  private

    SUFFIXES = ['.rb', '.rbw', '.so', '.bundle', '.dll', '.sl', '.jar']

    # Given a +loadpath+, a file's relative path, +relname+, and 
    # options hash, determine a matching file exists. Unless +:load+
    # option is +true+, this will check for each viable Ruby suffix.
    # If a match is found the full path to the file is returned,
    # otherwise +nil+.
    def lib_find(loadpath, relname)
      if SUFFIXES.include?(File.extname(relname))
        abspath = File.join(loadpath, relname)
        File.exist?(abspath) ? abspath : nil
      else
        SUFFIXES.each do |ext|
          abspath = File.join(loadpath, relname + ext)
          return abspath if File.exist?(abspath)
        end
      end
      nil
    end

Now I can do:

  require 'abbrev'
  require_ruby 'abbrev'

And it works fine. But, if I do:

  require_ruby 'abbrev'
  require 'abbrev'

The second is not loaded because somehow it seems to confuse it for the first in $LOADED_FEATURES.

I realize this is a very subtle issue and not likely to effect most people, but it presents a big problem for some of my work (e.g. wedge gem)

How is Ruby confusing the two? Can it be fixed? Or is there at least a work around?



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