Can't use `gem-install` command in pry

I tried to install a gem by using gem-install command in pry, but it failed.

% pry
pry(main) > gem-install pry-doc
NoMethodError: undefined method `split' for nil:NilClass
from /Users/ironsand/.rbenv/versions/2.2.2/lib/ruby/gems/2.2.0/gems/pry-0.10.1/lib/pry/rubygem.rb:60:in `install'

I could install the gem by using gem command from bash. Is there something I must configure to use gem-install command in pry?

Solution

I hadn't used PRY for a while.

Looking through the source code found the gem-install command code.

Look at your Gem.configuration['gem'] and you will find that it is nil.

It looks like this comes from your ~/.gemrc settings or default values.

In your ~/.gemrc file, if you place the line gem: ''

This solved the issue for me as it is no longer doing the split on nil, but on the assigned value for gem: key in the .gemrc file.