Trouble installing gems with bundler

Question

I'm new to Rails, following Michael Hartl's textbook. When I run $ bundle install I get the following error:

Bundler could not find compatible versions for gem "bundler":
  In Gemfile:
    rails (= 3.0.1) ruby depends on
      bundler (~> 1.0.0) ruby

  Current Bundler version:
    bundler (1.7.6)

This Gemfile requires a different version of Bundler.
Perhaps you need to update Bundler by running `gem install bundler`?

I then try $ gem install bundler which works fine:

Successfully installed bundler-1.7.6
Parsing documentation for bundler-1.7.6
1 gem installed

However, this doesn't solve the problem. I'm sensing this has something to do with version problems, but I'm not sure where to go with it...

Answer 1

The following :

In Gemfile:
    rails (= 3.0.1) ruby depends on
      bundler (~> 1.0.0) ruby

means the version of bundler required is greater than or equal to 1.0.0 but strictly less than 1.1.0. Rails 3 is depending on an old version of bundler. At this point of time, you should try out Rails 4 instead :)

You may read up more about the "version syntax" in http://guides.rubygems.org/patterns/#pessimistic_version_constraint

Answer 2

As @user3927334 has already stated the error you got is due to a version conflict between bundler and rails .

Most likely you have run rails new my_app with an outdated version of the rails gem.

gem install rails -v 4.2.0.beta4

Can be used to install a particular version of Rails. see Installing Rails . You should then remove your old app and rerun the app generator :

rails _4.2.0.beta4_ new hello_app 

If you indent to develop on your local machine I would recommend installing RVM (Ruby Version Manager) (as did previous versions of MH's Ruby on Rails Tutorial .)

It allows you to effortlessly switch between different versions of ruby and different sets of gems.