gem which cannot find gem despite it being installed

Question

I\'ve built my first gem but I don\'t seem to be able to get it to install correctly. I can issue the command

sudo gem install ceilingfish-toto

Answer 1

gem which ceilingfish-toto looks through the gem require path for a file named ceilingfish-toto.rb. Since there isn't one, it returns nothing. What would work for you is gem which toto, but since lib/ is not included in your gem spec, the lib files are not installed, so it doesn't exist.

Rerunning rake gemspec might fix the problem.

As an aside, you can check whether a gem is installed by its name by using gem list ceilingfish-toto which should show you it is installed, regardless of the files it has(it will also list the versions installed).

Answer 2

OK, so the problem here appears to be that there was a problem with my gemspec file. From what I can tell there absolutely has to be a file with the name lib/gem-name.rb so in this case I needed lib/ceilingfish-toto.rb.

This doesn't seem to be true for some other gems to operate correctly. For example mime-types or rest-client, even though they do not show up with gem which, they do actually work.

I'm not sure this is entirely correct yet, I'm sure there should be a way to get a gem with a hyphen in the name to behave correctly. If I find out I'll post back and let y'all know.

Answer 3

It's not the hyphen.

gem which searches for library files in gems, not gems. Compare:

$ gem which haml
/home/dave/.gem/ruby/1.8/gems/haml-3.0.12/lib/haml.rb
$ ls haml-3.0.12/lib/h*
haml  haml.rb  haml.rbc

Peachy. Note the existance of lib/haml.rb.

$ gem which rails
ERROR:  Can't find ruby library file or shared library rails
$ ls rails-2.3.8/lib/r*
rails_generator.rb  railties_path.rb  rubyprof_ext.rb  ruby_version_check.rb

There is no lib/rails.rb. But try:

$ gem which railties_path # not a gem
/home/dave/.gem/ruby/1.8/gems/rails-2.3.8/lib/railties_path.rb

So gem which ceilingfish-toto throws an error even when ceilingfish-toto is installed because there is no lib/ceilingfish-toto.rb file (there's not even a lib folder).