Bundler冲突-Heroku需要Bundler 2，但应用程序需要Bundler v <2

Question

Bundler is causing a build fail for my Heroku app. It is a ruby on rails app and was working perfectly and deployed on Heroku. I started getting the following build error only after I installed the datadog agent. The build error seemed easy enough to fix, but it has grown difficult.

After removing my Gemfile.lock and reinstalling to make sure bundler version was > 2.0, I then started getting another build error. This time it was that the bundler version my project requires is < 2:

remote:        Bundler Output: Activating bundler (< 2) failed:
remote:        Could not find 'bundler' (1.17.3) required by your /tmp/build_3b256cc6024c5dcfd1bd0d030688678a/Gemfile.lock.
remote:        To update to the lastest version installed on your system, run `bundle update --bundler`.
remote:        To install the missing version, run `gem install bundler:1.17.3`
remote:        Checked in 'GEM_PATH=vendor/bundle/ruby/2.5.0', execute `gem env` for more information
remote:        
remote:        To install the version of bundler this project requires, run `gem install bundler -v '< 2'`
remote: 
remote:  !     Failed to install gems via Bundler.

I updated the latest version on my system, like it suggests. But then I run back into the first error that Bundler V2 is required for the Heroku build step.

This is my Gemfile.lock:

  remote: https://rubygems.org/
  specs:
    actioncable (5.2.2)
      actionpack (= 5.2.2)
      nio4r (~> 2.0)
      websocket-driver (>= 0.6.1)
    actionmailer (5.2.2)
      actionpack (= 5.2.2)
      actionview (= 5.2.2)
      activejob (= 5.2.2)
      mail (~> 2.5, >= 2.5.4)
      rails-dom-testing (~> 2.0)
    actionpack (5.2.2)
      actionview (= 5.2.2)
      activesupport (= 5.2.2)
      rack (~> 2.0)
      rack-test (>= 0.6.3)
      rails-dom-testing (~> 2.0)
      rails-html-sanitizer (~> 1.0, >= 1.0.2)
    actionview (5.2.2)
      activesupport (= 5.2.2)
      builder (~> 3.1)
      erubi (~> 1.4)
      rails-dom-testing (~> 2.0)
      rails-html-sanitizer (~> 1.0, >= 1.0.3)
    active_model_serializers (0.10.9)
      actionpack (>= 4.1, < 6)
      activemodel (>= 4.1, < 6)
      case_transform (>= 0.2)
      jsonapi-renderer (>= 0.1.1.beta1, < 0.3)
    activejob (5.2.2)
      activesupport (= 5.2.2)
      globalid (>= 0.3.6)
    activemodel (5.2.2)
      activesupport (= 5.2.2)
    activerecord (5.2.2)
      activemodel (= 5.2.2)
      activesupport (= 5.2.2)
      arel (>= 9.0)
    activestorage (5.2.2)
      actionpack (= 5.2.2)
      activerecord (= 5.2.2)
      marcel (~> 0.3.1)
    activesupport (5.2.2)
      concurrent-ruby (~> 1.0, >= 1.0.2)
      i18n (>= 0.7, < 2)
      minitest (~> 5.1)
      tzinfo (~> 1.1)
    arel (9.0.0)
    aws-eventstream (1.0.1)
    aws-partitions (1.139.0)
    aws-sdk-core (3.46.1)
      aws-eventstream (~> 1.0)
      aws-partitions (~> 1.0)
      aws-sigv4 (~> 1.0)
      jmespath (~> 1.0)
    aws-sdk-kms (1.13.0)
      aws-sdk-core (~> 3, >= 3.39.0)
      aws-sigv4 (~> 1.0)
    aws-sdk-s3 (1.30.1)
      aws-sdk-core (~> 3, >= 3.39.0)
      aws-sdk-kms (~> 1)
      aws-sigv4 (~> 1.0)
    aws-sigv4 (1.0.3)
    builder (3.2.3)
    byebug (11.0.0)
    case_transform (0.2)
      activesupport
    concurrent-ruby (1.1.4)
    crass (1.0.4)
    erubi (1.8.0)
    ffi (1.0.11)
    globalid (0.4.2)
      activesupport (>= 4.2.0)
    i18n (1.5.3)
      concurrent-ruby (~> 1.0)
    jmespath (1.4.0)
    jsonapi-renderer (0.2.0)
    listen (3.1.5)
      rb-fsevent (~> 0.9, >= 0.9.4)
      rb-inotify (~> 0.9, >= 0.9.7)
      ruby_dep (~> 1.2)
    loofah (2.2.3)
      crass (~> 1.0.2)
      nokogiri (>= 1.5.9)
    mail (2.7.1)
      mini_mime (>= 0.1.1)
    marcel (0.3.3)
      mimemagic (~> 0.3.2)
    method_source (0.9.2)
    mimemagic (0.3.3)
    mini_mime (1.0.1)
    mini_portile2 (2.4.0)
    minitest (5.11.3)
    nio4r (2.3.1)
    nokogiri (1.10.1)
      mini_portile2 (~> 2.4.0)
    pg (1.1.4)
    puma (3.12.0)
    rack (2.0.6)
    rack-cors (1.0.2)
    rack-test (1.1.0)
      rack (>= 1.0, < 3)
    rails (5.2.2)
      actioncable (= 5.2.2)
      actionmailer (= 5.2.2)
      actionpack (= 5.2.2)
      actionview (= 5.2.2)
      activejob (= 5.2.2)
      activemodel (= 5.2.2)
      activerecord (= 5.2.2)
      activestorage (= 5.2.2)
      activesupport (= 5.2.2)
      bundler (>= 1.3.0)
      railties (= 5.2.2)
      sprockets-rails (>= 2.0.0)
    rails-dom-testing (2.0.3)
      activesupport (>= 4.2.0)
      nokogiri (>=a 1.6)
    rails-html-sanitizer (1.0.4)
      loofah (~> 2.2, >= 2.2.2)
    railties (5.2.2)
      actionpack (= 5.2.2)
      activesupport (= 5.2.2)
      method_source
      rake (>= 0.8.7)
      thor (>= 0.19.0, < 2.0)
    rake (12.3.2)
    rb-fsevent (0.10.3)
    rb-inotify (0.10.0)
      ffi (~> 1.0)
    ruby_dep (1.5.0)
    spring (2.0.2)
      activesupport (>= 4.2)
    spring-watcher-listen (2.0.1)
      listen (>= 2.7, < 4.0)
      spring (>= 1.2, < 3.0)
    sprockets (3.7.2)
      concurrent-ruby (~> 1.0)
      rack (> 1, < 3)
    sprockets-rails (3.2.1)
      actionpack (>= 4.0)
      activesupport (>= 4.0)
      sprockets (>= 3.0.0)
    sqlite3 (1.3.13)
    thor (0.20.3)
    thread_safe (0.3.6)
    tzinfo (1.2.5)
      thread_safe (~> 0.1)
    websocket-driver (0.7.0)
      websocket-extensions (>= 0.1.0)
    websocket-extensions (0.1.3)

PLATFORMS
  ruby

DEPENDENCIES
  active_model_serializers
  aws-sdk-s3
  byebug
  ffi (~> 1.0.9)
  listen (>= 3.0.5, < 3.2)
  nokogiri (~> 1.6, >= 1.6.7)
  pg
  puma (~> 3.11)
  rack-cors
  rails (~> 5.2.1)
  spring
  spring-watcher-listen (~> 2.0.0)
  sqlite3 (~> 1.3.6)
  tzinfo-data

RUBY VERSION
   ruby 2.5.1p57

BUNDLED WITH
   2.0.1

Here is my Gemfile if that helps

source 'https://rubygems.org'
git_source(:github) { |repo| "https://github.com/#{repo}.git" }

ruby '2.5.1'

# Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
gem 'rails', '~> 5.2.1'
# Use sqlite3 as the database for Active Record
gem 'pg'
gem 'ffi', '~> 1.0.9'
# Use Puma as the app server
gem 'puma', '~> 3.11'
# Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
# gem 'jbuilder', '~> 2.5'
# Use Redis adapter to run Action Cable in production
# gem 'redis', '~> 4.0'
# Use ActiveModel has_secure_password
# gem 'bcrypt', '~> 3.1.7'
gem 'active_model_serializers'

# Use ActiveStorage variant
# gem 'mini_magick', '~> 4.8'

# Use Capistrano for deployment
# gem 'capistrano-rails', group: :development

# Reduces boot times through caching; required in config/boot.rb

# Use Rack CORS for handling Cross-Origin Resource Sharing (CORS), making cross-origin AJAX possible
gem 'rack-cors'

group :development, :test do
  # Call 'byebug' anywhere in the code to stop execution and get a debugger console
  gem 'byebug', platforms: [:mri, :mingw, :x64_mingw]
  gem 'sqlite3', '~> 1.3.6'
end

group :development do
  gem 'listen', '>= 3.0.5', '< 3.2'
  # Spring speeds up development by keeping your application running in the background. Read more: https://github.com/rails/spring
  gem 'spring'
  gem 'spring-watcher-listen', '~> 2.0.0'
  gem 'nokogiri', '~> 1.6', '>= 1.6.7'
end


# Windows does not include zoneinfo files, so bundle the tzinfo-data gem
gem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw, :jruby]
gem "aws-sdk-s3", require: false

I'm really at a loss an appreciate your help. ANY SUGGESTIONS APPRECIATED!

Answer 1

The errors you are getting are coming from the remote computer, that is, the Heroku dyno. You can't follow the instructions in the warning (to update bundler) as you can't run arbitrary instructions on their servers. Heroku only support limited " carefully curated " versions of bundler.

Normally when the bundler versions don't match it just gives a warning, not an error, so you can potentially just ignore it. Personally I like to eliminate warnings (or supress them if elimination isn't possible) so that when new warnings pop up I am more likely to notice them and deal with them.

That being said, I was not able to "downgrade" my Gemfile.lock from 2.0.1 to 1.15.2. I had to first delete Gemfile.lock and then recreate it (presumably there are potentially breaking changes across these major versions). I suspect this is the second problem you encountered.

The best way around these warnings/errors is to match your local version of Bundler to Heroku's carefully curated version. That page above links to another page with the currently supported versions:
https://devcenter.heroku.com/articles/ruby-support#libraries

As of today that's version 2.0.1 for Gemfile.locks bundled with 2.x and 1.15.2 for everything else.

# To check which version(s) of bundler you have installed:
$ gem list | grep bundler
bundler (1.17.1)

# To install an older version
$ gem install bundler -v 1.15.2
Fetching: bundler-1.15.2.gem (100%)
...
1 gem installed

# To install supported version 2
$ gem install bundler -v 2.0.1
Fetching: bundler-2.0.1.gem (100%)
...
1 gem installed

# Check again:
$ gem list | grep bundler
bundler (2.0.1, 1.17.1, 1.15.2)

# Bundle with the latest installed version
$ bundle install

# Try to bundle with an older version (may break)
$ bundle _1.15.2_ install
Traceback...
Could not find 'bundler' (2.0.1) required by your Gemfile.lock (Gem::GemNotFoundException)

# Actually bundle with an older version
$ rm Gemfile.lock
$ bundle _1.15.2_ install