Kernel#gem
# File tmp/rubies/ruby-4.0.0/lib/rubygems/core_ext/kernel_gem.rb, line 35
def gem(gem_name, *requirements) # :doc:
skip_list = (ENV["GEM_SKIP"] || "").split(/:/)
raise Gem::LoadError, "skipping #{gem_name}" if skip_list.include? gem_name
if gem_name.is_a? Gem::Dependency
unless Gem::Deprecate.skip
warn "#{Gem.location_of_caller.join ":"}:Warning: Kernel.gem no longer "\
"accepts a Gem::Dependency object, please pass the name "\
"and requirements directly"
end
requirements = gem_name.requirement
gem_name = gem_name.name
end
dep = Gem::Dependency.new(gem_name, *requirements)
loaded = Gem.loaded_specs[gem_name]
return false if loaded && dep.matches_spec?(loaded)
spec = dep.to_spec
if spec
if Gem::LOADED_SPECS_MUTEX.owned?
spec.activate
else
Gem::LOADED_SPECS_MUTEX.synchronize { spec.activate }
end
end
end
Use Kernel#gem to activate a specific version of gem_name.
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).
Kernel#gem only loads prerelease versions when prerelease requirements are given:
gem 'rake', '>= 1.1.a', '< 2'
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