Heroku buliid fails on Bundler version regardless of which is installed - ruby-on-rails

Question

I can't seem to configure my rails app properly. I had a perfectly working rails app deployed on Heroku. I added the datadog buildpack and then started getting the following build error:
remote: ! You must use Bundler 2 or greater with this lockfile.
After removing my Gemfile.lock and reinstalling and making sure bunder version was > 2.0, I then started getting another build error. This time it was that the bundler version my project needs 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: !
remote: ! Failed to install gems via Bundler.
remote: !
remote: ! Push rejected, failed to compile Ruby app.
remote:
remote: ! Push failed
remote: Verifying deploy...
I'm not sure how to move forward debugging this error. I don't know how to access the /tmp/build folder and I'm not sure what I would do if I did.
Please any direction or suggestions would be greatly appreciated.
I've already tried pushing to heroku master with various versions of bundler. There is always a problem with the build. I feel like there are multiple areas where bundler is required in the build and in the actual project, and that they require different versions, but I don't know how to find them.
Here is my Gemfile:
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
and here is my Gemfile.lock
GEM
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 (>= 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
I'd like to be able to find where the areas are in my code that are requiring different versions of bundler. Or be able to circumvent the issue with a different gem. If anyone can help me get the Heroku build to work I would be very grateful.