Fails to install gem if it has prerelease gems in its dependencies. #43
Description
For example:
$ gem specific_install 'rails/rails'
or
$ gem specific_install 'https://github.com/rails/rails.git'
or
$ gem specific_install -l 'https://github.com/rails/rails.git'
results in:
$ ERROR: While executing gem ... (Gem::UnsatisfiableDependencyError)
Unable to resolve dependency: 'rails (= 5.2.0.alpha)' requires 'railties (= 5.2.0.alpha)'
and if we start to install dependencies one-by-one, we also got stuck:
$ gem specific_install 'https://github.com/rails/rails.git' -d activesupport` # -Success
$ gem list activesupport
$ activesupport (5.2.0.alpha, 5.1.4)
$ gem specific_install 'https://github.com/rails/rails.git' -d actionview
$ ERROR: While executing gem ... (Gem::DependencyError)
Unresolved dependency found during sorting - activesupport (>= 4.2.0) (requested by rails-dom-testing-2.0.3)
This is caused by the presence of prerelease gems in gem's dependencies. If we initialize Gem::DependencyInstaller with prerelease:true, then at least gem specific_install 'rails/rails' -d actionview seems to work fine. So, I think it would be convenient to add some command line flag, that will set prerelease option to true, if provided.