Do you want ruby/bundler to skip a gem install on a certain platform, but any other platform needs that gem?

The obvious answer would be the following, which would result in also clobbering your Gemfile.lock if bundling on macOS:

gem "openssl", "= 3.2.0" if RUBY_PLATFORM !~ /darwin/

But bundler has its own method, install_if , to accomplish such a conditional install.

install_if -> { RUBY_PLATFORM !~ /darwin/ } do
  openssl "= 3.2.0"
end