Understanding bundler dependency resolution

Question

I am migrating an application from Rails 4 to Rails 5 but am struggling to get a complete bundle due to dependency conflicts. I am a bit confused as to why this is a problem as I don't completely understand why the bundler cannot resolve the dependencies.

In this case, I am on Windows. I have installed Ruby 2.5.5 using BitNami Ruby and installed Rails 5.2.3. I deleted Gemfile.lock and ran bundle install. The Gemfile specifies Ruby 2.5.5 and Rails 5.2.3. No other gems have version requirements specified. Bundle is at 1.17.3.

My interest on this issue, other converting this particular application, is to better understand how bundle resolves dependencies. Looking at the bundler documentation, I haven't discovered the reason for some conflicts. As an example, why would the bundler not accept actionpack 5.2.3 in this case:

Bundler could not find compatible versions for gem "actionpack":
  In Gemfile:
    jquery-datatables-rails x64-mingw32 was resolved to 3.4.0, which depends on
      actionpack (>= 3.1) x64-mingw32

    rails (= 5.2.3) x64-mingw32 was resolved to 5.2.3, which depends on
      actionpack (= 5.2.3) x64-mingw32

    rspec-rails x64-mingw32 was resolved to 3.8.2, which depends on
      actionpack (>= 3.0) x64-mingw32

    simple_form x64-mingw32 was resolved to 4.1.0, which depends on
      actionpack (>= 5.0) x64-mingw32

    rails (= 5.2.3) x64-mingw32 was resolved to 5.2.3, which depends on
sprockets-rails (>= 2.0.0) x64-mingw32 was resolved to 3.2.1, which
depends on
        actionpack (>= 4.0) x64-mingw32

Getting an understanding of this particular case would really help me. I'd appreciate your assistance.

Gemfile is as follows:

source 'https://rubygems.org'
ruby '2.5.5' 
gem 'rails', '5.2.3'
gem 'aasm'
gem 'active_model-errors_details'
gem 'acts_as_tenant'
gem 'acts_as_xlsx'
gem 'addressable'
gem 'autoprefixer-rails'
gem 'awesome_print'
gem 'aws-sdk'
gem 'aws-sdk-core'
gem 'aws-sdk-resources'
gem 'axlsx'
gem 'axlsx_rails'
gem 'better_delayed_job_web'
gem 'bindex'
gem 'bootstrap-sass'
gem 'delayed_job'
gem 'delayed_job_active_record'
gem 'exception_notification'
gem 'exception_notification-rake'
gem 'figaro'
gem 'ffi'
gem 'font-awesome-sass'
gem 'forgery'
gem 'htmlentities'
gem 'jquery-datatables-rails'
gem 'jquery-rails'
gem 'jquery-turbolinks'
gem 'jquery-ui-rails'
gem 'json_pure'
gem 'logging'
gem 'nokogiri'
gem 'paloma'
gem 'pg'
gem 'phony'
gem 'phony_rails'
gem 'rake'
gem 'redis'
gem 'responders'
gem 'robocop'
gem 'rolify'
gem 'roo'
gem 'roo-xls'
gem 'rubyzip'
gem 'sass'
gem 'sass-rails'
gem 'simple_form'
gem 'smarter_csv'
gem 'sorcery'
gem 'spreadsheet'
gem 'sprockets'
gem 'sprockets-rails'
gem 'turbolinks'
gem 'twilio-ruby'
gem 'tzinfo-data'
gem 'uglifier'
gem 'will_paginate'
group :production, :staging do
  gem 'rails_12factor'
  platforms :ruby do
    gem 'unicorn'
  end
end
group :development do
  gem 'better_errors'
  gem 'binding_of_caller'
  gem 'brakeman'
  gem 'bullet'
  gem 'coffee-rails-source-maps'
  gem 'meta_request'
  gem 'require_reloader'
  gem 'quiet_assets'
  gem 'rails_layout'
  gem 'rubocop'
  gem 'web-console'
end
group :development, :test do
  gem "faker"
  gem "squasher"
  gem 'fabrication'
  gem 'factory_bot_rails'
  gem 'letter_opener'
  gem 'method_source'
  gem 'rspec'
  gem 'rspec-collection_matchers'
  gem 'rspec-core'
  gem 'rspec-expectations'
  gem 'rspec-mocks'
  gem 'rspec-rails'
  gem 'rspec-support'
  gem 'thin'
end
group :test do
  gem "launchy"
  gem 'capybara'
  gem 'chromedriver-helper'
  gem 'database_cleaner'
  gem 'email_spec'
  gem 'json_spec'
  gem 'mocha'
  gem 'selenium-webdriver'
  gem 'shoulda-callback-matchers'
  gem 'shoulda-matchers'
end

Answer 1

When you look at the complete output from your bundle install it is pretty long:

Bundler could not find compatible versions for gem "actionpack":
  In Gemfile:
    jquery-datatables-rails was resolved to 3.4.0, which depends on
      actionpack (>= 3.1)

    rails (= 5.2.3) was resolved to 5.2.3, which depends on
      actionpack (= 5.2.3)

    rspec-rails was resolved to 3.8.2, which depends on
      actionpack (>= 3.0)

    simple_form was resolved to 4.1.0, which depends on
      actionpack (>= 5.0)

    rails (= 5.2.3) was resolved to 5.2.3, which depends on
      sprockets-rails (>= 2.0.0) was resolved to 3.2.1, which depends on
        actionpack (>= 4.0)

Bundler could not find compatible versions for gem "activemodel":
  In Gemfile:
    rails (= 5.2.3) was resolved to 5.2.3, which depends on
      activemodel (= 5.2.3)

    web-console was resolved to 4.0.1, which depends on
      activemodel (>= 6.0.0)

Bundler could not find compatible versions for gem "activerecord":
  In Gemfile:
    acts_as_xlsx was resolved to 1.0.6, which depends on
      activerecord (>= 2.3.9)

    better_delayed_job_web was resolved to 1.3.12, which depends on
      activerecord (> 3.0.0)

    delayed_job_active_record was resolved to 4.1.4, which depends on
      activerecord (>= 3.0, < 6.1)

    rails (= 5.2.3) was resolved to 5.2.3, which depends on
      activerecord (= 5.2.3)

Bundler could not find compatible versions for gem "activesupport":
  In Gemfile:
    active_model-errors_details was resolved to 1.1.1, which depends on
      activesupport

    delayed_job was resolved to 4.1.8, which depends on
      activesupport (>= 3.0, < 6.1)

    exception_notification-rake was resolved to 0.3.0, which depends on
      exception_notification (~> 4.2.0) was resolved to 4.2.2, which depends on
        activesupport (>= 4.0, < 6)

    rails (= 5.2.3) was resolved to 5.2.3, which depends on
      activesupport (= 5.2.3)

    rspec-rails was resolved to 3.8.2, which depends on
      activesupport (>= 3.0)

    shoulda-matchers was resolved to 4.1.2, which depends on
      activesupport (>= 4.2.0)

    rails (= 5.2.3) was resolved to 5.2.3, which depends on
      sprockets-rails (>= 2.0.0) was resolved to 3.2.1, which depends on
        activesupport (>= 4.0)

Bundler could not find compatible versions for gem "axlsx":
  In Gemfile:
    axlsx

    acts_as_xlsx was resolved to 1.0.6, which depends on
      axlsx (>= 1.0.13)

    axlsx_rails was resolved to 0.5.2, which depends on
      axlsx (>= 2.0.1)

Bundler could not find compatible versions for gem "exception_notification":
  In Gemfile:
    exception_notification

    exception_notification-rake was resolved to 0.3.0, which depends on
      exception_notification (~> 4.2.0)

Bundler could not find compatible versions for gem "rails":
  In Gemfile:
    rails (= 5.2.3)

    acts_as_tenant was resolved to 0.4.4, which depends on
      rails (>= 4.0)

    axlsx_rails was resolved to 0.1.5, which depends on
      rails (>= 3.1)

Maybe too long, and there is a lot of noise in the output. But if you try to dig through you will find some interesting lines:

    web-console was resolved to 4.0.1, which depends on
      activemodel (>= 6.0.0)

this means that web-console v4.0.1 needs at least activemodel gem 6.0.0, so you should limit web-console to valid version for rails 5, which is 3.7.0, version in your gemfile:

  gem web-console, '< 4.0'

now when you try to run bundle install again it will show you similar errors again but there will be some differences. In new output you will find following difference:

    active_model-errors_details was resolved to 1.1.1, which depends on
      activemodel (>= 4.0, < 5.0.0.alpha)

This means that active_model-errro_details cannot be run with Rails 5. According to Rubygems, this gem cannot be run with Rails 5.2.3 see https://rubygems.org/gems/active_model-errors_details, so I commented it out in gemfile:

# gem 'active_model-errors_details'

and tried to run bundle install again. There are still some compatibility errors with gem versions this time it is quiet_assets gem:

Bundler could not find compatible versions for gem "railties":
  In Gemfile:
    quiet_assets was resolved to 1.0.1, which depends on
      railties (~> 3.1)

You can see it dependes on Rails 3.x. If you look at the rubygems, you will see that even the latest version of quiet_assets cannot be run with Rails 5. Again I removed the gem from the Gemfile:

 # gem 'quiet_assets'

Now when you try to run bundle install all of the gems version problems will be solved and gems will be successfully installed.

It is a bit messy and there is a lot of noise in the error output, but if you read it carefully, you will find what is wrong.