Bundler: You must use Bundler 2 or greater with this lockfile

Question

I\'m working with heroku and every time I try to push my app this message shows out:

remote: Compressing source files... done.
remote: Building source:
remo         


        

Answer 1

Heroku does not use Bundler 2.0, but 1.15.2, as the tracelog hints.

As far as I am aware, the "workaround" is to create your own buildpack, or simple fork their own:

Open lib/language_pack/ruby.rb in your editor, and change the following line:

BUNDLER_VERSION = "1.11.2"

(README.md at https://github.com/heroku/heroku-buildpack-ruby)

Update: As of Ruby 2.6.1 and Bundler 2.0.1, Heroku now does support Bundler 2.0.1. https://devcenter.heroku.com/articles/bundler-version#known-upgrade-issues

This is not the case for Ruby 2.6.0, as this is incorrectly invoked from binstubs, as @Schneems has mentioned in the comment. He has kindly reported this as a Ruby Bug #15622