Always the same version of gem is installing?

Question

I am trying to make new ruby on rails project with:

rails new . --no-ri --no-rdoc

But at the end of execution of this command I got:

         run  bundle install
Bundler could not find compatible versions for gem "bundler":
  In Gemfile:
    rails (= 4.2.6) was resolved to 4.2.6, which depends on
      bundler (< 2.0, >= 1.3.0)

  Current Bundler version:
    bundler (2.2.27)

Your bundle requires a different version of Bundler than the one you're running.
Install the necessary version with `gem install bundler:2.0.0.pre.3` and rerun bundler using `bundle _2.0.0.pre.3_ install`
Fetching gem metadata from https://rubygems.org/.............
Resolving dependencies...
         run  bundle exec spring binstub --all
Traceback (most recent call last):
    13: from /usr/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in `require'
    12: from /usr/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in `require'
    11: from /var/lib/gems/2.5.0/gems/bundler-2.2.27/lib/bundler/setup.rb:20:in `<top (required)>'
    10: from /var/lib/gems/2.5.0/gems/bundler-2.2.27/lib/bundler/ui/shell.rb:88:in `silence'
     9: from /var/lib/gems/2.5.0/gems/bundler-2.2.27/lib/bundler/ui/shell.rb:136:in `with_level'
     8: from /var/lib/gems/2.5.0/gems/bundler-2.2.27/lib/bundler/setup.rb:20:in `block in <top (required)>'
     7: from /var/lib/gems/2.5.0/gems/bundler-2.2.27/lib/bundler.rb:149:in `setup'
     6: from /var/lib/gems/2.5.0/gems/bundler-2.2.27/lib/bundler/runtime.rb:18:in `setup'
     5: from /var/lib/gems/2.5.0/gems/bundler-2.2.27/lib/bundler/definition.rb:234:in `specs_for'
     4: from /var/lib/gems/2.5.0/gems/bundler-2.2.27/lib/bundler/definition.rb:483:in `materialize'
     3: from /var/lib/gems/2.5.0/gems/bundler-2.2.27/lib/bundler/definition.rb:262:in `resolve'
     2: from /var/lib/gems/2.5.0/gems/bundler-2.2.27/lib/bundler/resolver.rb:23:in `resolve'
     1: from /var/lib/gems/2.5.0/gems/bundler-2.2.27/lib/bundler/resolver.rb:46:in `start'
/var/lib/gems/2.5.0/gems/bundler-2.2.27/lib/bundler/resolver.rb:59:in `rescue in start': Bundler could not find compatible versions for gem "bundler": (Bundler::VersionConflict)
  In Gemfile:
    rails (= 4.2.6) was resolved to 4.2.6, which depends on
      bundler (< 2.0, >= 1.3.0)

  Current Bundler version:
    bundler (2.2.27)

Your bundle requires a different version of Bundler than the one you're running.
Install the necessary version with `gem install bundler:1.11.2` and rerun bundler using `spring _1.11.2_ binstub --all`

After that I removed ruby, so that with commands ruby -v I got:

bash: /home/iva/.rbenv/shims/ruby: No such file or directory

Then I installed again ruby and installed gem with gem install bundler:1.11.2. But after this installation with checking versions of ruby and gem I got:

ruby -v
ruby 2.5.1p57 (2018-03-29 revision 63029) [x86_64-linux]
gem -v
2.7.6

I don't know how is this 2.7.6 version of gem when I gave command with version 1.11.2? So it seems like some circle, and I don`t know how to get out of it. I am installing ruby, it requires older version of gem, but with any command newest version of gem is always installing at my computer. What should I do in this situation?

============================================================= Response for this commands are:

rbenv versions
* 2.5.1 (set by /home/iva/.rbenv/version)
echo $PATH
/home/iva/.rbenv/shims:/home/iva/.rbenv/bin:/home/iva/.rbenv/shims:/home/iva/.rbenv/bin:/home/iva/.rbenv/shims:/home/iva/.rbenv/bin:/home/iva/.rbenv/shims:/home/iva/.rbenv/bin:/home/iva/.rbenv/shims:/home/iva/.rbenv/bin:/home/iva/.rbenv/shims:/home/iva/.rbenv/bin:/home/iva/bin:/home/iva/.local/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin:/home/iva/.rvm/bin:/home/iva/.rvm/bin:/home/iva/.rvm/bin:/home/iva/.rvm/bin:/home/iva/.rvm/bin

Answer 1

1. Why are you creating a new rails project with rails version 4.2.6?? Is this really intentional?! Rails 4.2.6 was released on March 11, 2016. It is fairly old/outdated, and no longer supported. The latest version of rails is 6.1.4.1.

2. The error message said that your version of bundler is incompatible with the version of rails. There is nothing in that error to suggest you needed to reinstall ruby, but I guess it didn't do any harm...

3. gem and bundler are different things. To check the version of bundler, run: bundle -v, not gem -v. You should hopefully see 1.11.2 as you expected.

In short:

• I don't see anything wrong with your current setup. If you reinstall rails v4.2.6, then run rails new, I'd expect it to work. Your confusion seems to be between comparing versions of different things (namely ruby, gem and bundler).
• This confusion would have been avoided if you'd just installed the latest version of everything. I'm not clear why you're trying to create a new rails project with such an old version. Maybe you've got a good reason for that decision, and that's fine; but if not, then just use the latest versions.