The Gem Wedge Plugin converts the Wedge library ‘wedge/gem.rb’ into a RubyGems plugin, so that it is automatically loaded whenever RubyGems is loaded.

One of the rarely mention edge cases with the way in which RubyGems loads library files, and in fact the way Ruby’s load system works in general, is that the “lib space” is a free for all. Any library can drop any file into their package’s lib/ directory and potentially clobber a file of the same name in some one else’s library. Now, a good gem citizen knows to put their scripts in a directory with the same name as their gem package, nonetheless you might be surprised to see how often this simple but important practice is violated. Consequently the order in which such gems are searched becomes of paramount importance –something that worked just fine on one machine can suddenly stop working on another for no obvious reason.

It is also worth noting that the recent crop of gem isolation systems, such as Bundler and Isolate, while serving to reduce the likelihood of possible name clashes still do not fully remedy the issue. They merely reduce the number to gems that could cause the problem for any given dependent application.

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See the INFRACTIONS.rdoc file for examples.

The Gem Wedge solves the issue entirely by allowing you to load files directly for a single gem and only that gem. It does so by adding a new valid syntax to Ruby’s #load and #require methods. As an example, let’s say we wanted to load the troff.rb script from the unroller library.

require 'unroller:troff'

The colon is used to separate the gem name from the rest of the pathname. With this we can be 100% certain that the troff.rb file was required from the unroller gem and not a ‘troff.rb’ file from any other gem that might have created a script by the same name.

Using the usual ‘gem` command:

$ gem install gem-wedge

Keep in mind that this installs a RubyGems plugin. Once installed gem-wedge will be loaded automatically whenever RubyGems itself is loaded.

Copyright © 2010 Thomas Sawyer

Apache 2.0 License

(See LICENSE file for details.)