"You must use Bundler 2 or greater..." Error

rails -v
Rails 5.2.3
ruby -v
ruby 2.6.1p33 (2019-01-30 revision 66950) [x86_64-linux]
bundler -v
Bundler version 2.0.1

On creating a new app and trying rake db:create i get: You must use Bundler 2 or greater with this lockfile. even after deleting the lockfile and re-running bundle install or bundle update I get the same thing. The only way to make it work is to run bundle exec rake db:create. But then, to run migrations it will just keep getting the same error message.

Any ideas?

Try upgrading to Ruby 2.6.3 (it's the latest version anyways).

There was an issue in Ruby core that they mentioned here in this discussion about the issue. https://github.com/bundler/bundler/issues/6937

This Bundler 2 stuff has been an absolute mess.