How to add dependency of a local gem to a rails plugin/engine, in .gemspec file

Question

I had tried in this way：

 s.add_dependency \'gem\', :path => \'../gem\'

like add gem in the gemfile, but it doesn\'t work,

Answer 1

Sometimes you want to embed one gem into another gem, nevermind why. You can reference one gempec from another to completely encapsulate a local gem.

require "rubygems"

embedded_gemspec = Gem::Specification::load("path/to/internal.gemspec")

Gem::Specification.new do |spec|
  spec.name          = "gem_that_contains_another_gem"
  # spec.whatever,   = whole bunch of other info

  #                     our files               + other gem's files
  spec.files         = ['file1.rb', 'file2.rb'] + embedded_gemspec.files

  # our dependencies
  spec.add_dependency 'nokogiri'
  # other gem's dependencies
  embedded_gemspec.runtime_dependencies.each { |d| spec.add_dependency d }

end

EDIT: this appears to only work locally. If you try to install this gemspec from, say, a git repo, it won't know where to get embedded_gemspec (even though embedded_gemspec's dependencies come in just fine).