Rubygems: I didn't know the current Ruby version when error was occured caused by old version of Ruby.

[bake0937]

I'm having a problem or would like to suggest a feature.

My current problem is that I didn't know the current Ruby version when error was occured caused by old version of Ruby.

This issue is related to:

• [ ] Network problems
• [x] Installing a library
• [ ] Publishing a library
• [ ] The command line gem
• [ ] Other

Here are my current environment details:

With ruby ​​version set to 2.1.3p242 Installing rails has the following result.

$ gem install rails
Fetching: activesupport-5.0.0.1.gem (100%)
ERROR:  Error installing rails:
    activesupport requires Ruby version >= 2.2.2.

In this error message the user don't know how to check the current version.
I propose the following two methods

1. Appending #{Ruby version} to error message

$ gem install rails
Fetching: activesupport-5.0.0.1.gem (100%)
ERROR:  Error installing rails:
    activesupport requires Ruby version >= 2.2.2. current version is #{Ruby version}

1. Describing how to check version

$ gem install rails
Fetching: activesupport-5.0.0.1.gem (100%)
ERROR:  Error installing rails:
    activesupport requires Ruby version >= 2.2.2. please execute 'ruby -v'

[segiddins]

Something like (1) seems reasonable, and we ought to do the same on rubygems version mismatches

[bronzdoc]

Should we add that ruby version message whenever a Gem::InstallError is raised?

[segiddins]

@bronzdoc only on Gem::RuntimeRequirementNotMetError, I think