I'm a Rails newb who's trying out Rails on a DigitalOcean droplet. The installations seemed to work fine, but I'm getting a curious error message when I try to generate a scaffold:
DO 10:48 Rails/simple (master) → rails generate scaffold User name:string email:string
Traceback (most recent call last):
5: from bin/rails:3:in `<main>'
4: from bin/rails:3:in `load'
3: from /home/tony/rails/simple/bin/spring:10:in `<top (required)>'
2: from /home/tony/rails/simple/bin/spring:10:in `new'
1: from /home/tony/.rvm/rubies/ruby-2.6.0/lib/ruby/2.6.0/bundler/lockfile_parser.rb:95:in `initialize'
/home/tony/.rvm/rubies/ruby-2.6.0/lib/ruby/2.6.0/bundler/lockfile_parser.rb:108:in `warn_for_outdated_bundler_version': You must use Bundler 2 or greater with this lockfile. (Bundler::LockfileError)
DO 10:49 Rails/simple (master) → bundle list bundler
/home/tony/.rvm/gems/ruby-2.6.0/gems/bundler-2.0.1
DO 10:50 Rails/simple (master) → gem list bundler
*** LOCAL GEMS ***
bundler (2.0.1, default: 1.17.2)
bundler-unload (1.0.2)
rubygems-bundler (1.4.5)
I.e., the current Bundler gem is version 2.0.1, but Rails still thinks it's insufficient.
I can't find anything similar on the web. The only red flag I can see is that the bundler gem shows a default version of 1.17.2. How do I begin to diagnose the problem?
I ran into the same issue & resolved it by downgrading with gem uninstall bundler, followed by gem install bundler -v 1.17.3 to revert back to the last pre 2 version.
I saw this across 3 separate systems using different version managers (ASDF, rbenv, rvm) and this resolved the issue.
There is some information on getting both versions to play nicely here. The root cause of this issue may have been a bug (which appears to have since been fixed)
Per the comment from @MatijsvanZuijlen below, and the bundler documentation, you should also be able to specify which version of bundler you want to use at runtime with bundle _1.17.3_ install