Module | Kernel |
In: |
lib/rubygems/custom_require.rb
lib/rubygems.rb |
require | -> | gem_original_require |
The Kernel#require from before RubyGems was loaded. |
Use Kernel#gem to activate a specific version of gem_name.
version_requirements is a list of version requirements that the specified gem must match, most commonly "= example.version.number". See Gem::Requirement for how to specify a version requirement.
If you will be activating the latest version of a gem, there is no need to call Kernel#gem, Kernel#require will do the right thing for you.
Kernel#gem returns true if the gem was activated, otherwise false. If the gem could not be found, didn‘t match the version requirements, or a different version was already activated, an exception will be raised.
Kernel#gem should be called before any require statements (otherwise RubyGems may load a conflicting library version).
In older RubyGems versions, the environment variable GEM_SKIP could be used to skip activation of specified gems, for example to test out changes that haven‘t been installed yet. Now RubyGems defers to -I and the RUBYLIB environment variable to skip activation of a gem.
Example:
GEM_SKIP=libA:libB ruby -I../libA -I../libB ./mycode.rb
When RubyGems is required, Kernel#require is replaced with our own which is capable of loading gems on demand.
When you call require ‘x‘, this is what happens:
The normal require functionality of returning false if that file has already been loaded is preserved.