gemsets

A gemset is a named collection of RubyGems installed for a specific Ruby interpreter, most commonly in the context of the Ruby Version Manager (RVM). Gemsets are used to isolate gems between projects or environments so that installing a new library for one project does not affect others.

In RVM, gemsets are scoped to a particular Ruby version. The combination of the Ruby version and a gemset name identifies a distinct GEM_HOME and GEM_PATH. Activating a gemset is done by selecting the Ruby version and gemset, for example: rvm use 2.7.2@myproject. When active, any gem installation goes into that gemset, keeping the gem ecosystems separate across projects and versions.

Common operations include creating, listing, and deleting gemsets. For example: rvm gemset create myproject creates a new gemset; rvm gemset list lists available gemsets for the current Ruby; rvm gemset delete myproject removes it. Some workflows use an empty gemset or a "default" gemset to share baseline gems, while others create one per project to maximize isolation.

Relation to Bundler and workflows: Gemsets isolate gems, but they do not by themselves pin exact dependencies; Bundler remains the standard tool for per-project dependency resolution via Gemfile.lock. Using gemsets together with Bundler provides reproducible environments across machines and Ruby versions. Limitations include reliance on RVM; other Ruby managers may implement different isolation mechanisms, and gemsets do not replace the need for explicit dependency management.

See also: Ruby Version Manager (RVM), Bundler, RubyGems.