问题
I have a gem called "something".
I would like to add pry as a development dependency when developing the gem. However I don't know how to load it.
If I have "require something" inside lib/something.rb , when I release the gem, it throws a LoadError, because pry is only a development dependency.
At the same time I don't want to keep adding and removing pry when I am committing code.
What is the best way to require pry only when developing the application, but not require it as a dependency for the gem?
回答1:
You can use the add_development_dependency in the gemspec file. You'll still have to require it in your lib/something.rb file within a begin .. rescue LoadError block. (Edit 2, see below)
In your case, it will be something like the following:
spec.add_development_dependency 'pry', '~> 0.9.12.2'
The purpose of add_development_dependency is to separate the gems into dependencies that get installed when you execute gem install mygem vs development-only dependencies that are installed only when you execute gem install mygem --development.
Edit: @Pierre-Louis Gottfrois' solution
Modify the Gemfile directly and add a test group. This question describes the process. This does not appear to be a preferred solution according to Yehuda Katz.
Edit 2: begin require ... rescue LoadError is apparently a common practice for Ruby scripts, according to this Making Ruby Gems article.
回答2:
I think I found a workaround for that.
If you configure bundler to use pry as your console with
$ bundle config console pry
Then pry is itself required and you don't need to explicitly require in your source files.
Plus, you get a history on pressing ' ↑ '.
来源：https://stackoverflow.com/questions/18335229/how-to-add-pry-when-developing-a-ruby-gem