Say you have a Ruby project A and you install the gem
make_everything_work so that project A will work on the system you are developing on. It would have a line in the gemfile like this
# Project A: Gemfile gem 'make_everything_work', '~> 1.0' ...
as well as a line elsewhere in the code like this
# Project A: other file require 'make_everything_work' ...
Then you start another project B that also makes use of the gem
make_everything_work, however, you never list it in your Gemfile or gemspec file.
# Project B: other file require 'make_everything_work' ...
The project still works on your machine, because you already installed the gem for project A, even though you never included it in your Gemfile dependencies.
Is there a way to check that any gems required by your project are listed as a dependency in your Gemfile/gemspec file?