heroku push error: “Could not detect rake tasks”

Question

I\'m trying to deploy a basic app and it\'s not working. Using

git push heroku master 

I got this error message:

remote:          


        

Answer 1

You may also want to add PG Gem file in production in your gem file

GemFile

group :production do
 gem 'pg'
 gem 'rails_12factor'
end

group :development do
 gem 'sqlite3'
end

OR:

# Use sqlite3 as the database for Active Record
gem 'sqlite3', group: [:development, :test]

gem 'rails_12factor', group: :production
gem 'pg', group: :production

Once you added that there save and run the following:

Terminal

gem install bundler
bundle install
git add .
git commit -m "Some comment here..."
git push heroku master

Answer 2

Since this post came up repeatedly looking for my answer, hopefully this helps someone:

I was getting a similar error on Heroku when deploying updates to an app that was already up and running. The build process wasn't finding basic commands. This is what my error message looked like:

-----> Installing node-v12.16.2-linux-x64
-----> Detecting rake tasks
 !
 !     Could not detect rake tasks
 !     ensure you can run `$ bundle exec rake -P` against your app
 !     and using the production group of your Gemfile.
 !     /tmp/build_a61ee567/bin/rake: line 1: require_relative: command not found
 !     /tmp/build_a61ee567/bin/rake: line 2: require: command not found
 !     /tmp/build_a61ee567/bin/rake: line 3: Rake.application.run: command not found
 !
/tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/helpers/rake_runner.rb:106:in `load_rake_tasks!': Could not detect rake tasks (LanguagePack::Helpers::RakeRunner::CannotLoadRakefileError)
ensure you can run `$ bundle exec rake -P` against your app
and using the production group of your Gemfile.
/tmp/build_a61ee567/bin/rake: line 1: require_relative: command not found
/tmp/build_a61ee567/bin/rake: line 2: require: command not found
/tmp/build_a61ee567/bin/rake: line 3: Rake.application.run: command not found
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/ruby.rb:1068:in `rake'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/rails4.rb:84:in `block (2 levels) in run_assets_precompile_rake_task'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/base.rb:190:in `log'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/rails4.rb:78:in `block in run_assets_precompile_rake_task'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/instrument.rb:18:in `block (2 levels) in instrument'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/instrument.rb:40:in `yield_with_block_depth'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/instrument.rb:17:in `block in instrument'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/vendor/ruby/heroku-18/lib/ruby/2.6.0/benchmark.rb:308:in `realtime'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/instrument.rb:16:in `instrument'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/base.rb:50:in `instrument'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/base.rb:46:in `instrument'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/rails4.rb:77:in `run_assets_precompile_rake_task'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/ruby.rb:112:in `block (2 levels) in compile'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/ruby.rb:1089:in `allow_git'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/ruby.rb:105:in `block in compile'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/instrument.rb:18:in `block (2 levels) in instrument'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/instrument.rb:40:in `yield_with_block_depth'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/instrument.rb:17:in `block in instrument'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/vendor/ruby/heroku-18/lib/ruby/2.6.0/benchmark.rb:308:in `realtime'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/instrument.rb:16:in `instrument'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/base.rb:50:in `instrument'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/base.rb:46:in `instrument'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/ruby.rb:94:in `compile'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/rails2.rb:62:in `block in compile'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/instrument.rb:18:in `block (2 levels) in instrument'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/instrument.rb:40:in `yield_with_block_depth'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/instrument.rb:17:in `block in instrument'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/vendor/ruby/heroku-18/lib/ruby/2.6.0/benchmark.rb:308:in `realtime'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/instrument.rb:16:in `instrument'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/base.rb:50:in `instrument'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/base.rb:46:in `instrument'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/rails2.rb:60:in `compile'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/rails3.rb:42:in `block in compile'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/instrument.rb:18:in `block (2 levels) in instrument'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/instrument.rb:40:in `yield_with_block_depth'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/instrument.rb:17:in `block in instrument'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/vendor/ruby/heroku-18/lib/ruby/2.6.0/benchmark.rb:308:in `realtime'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/instrument.rb:16:in `instrument'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/base.rb:50:in `instrument'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/base.rb:46:in `instrument'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/rails3.rb:41:in `compile'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/rails4.rb:41:in `block in compile'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/instrument.rb:18:in `block (2 levels) in instrument'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/instrument.rb:40:in `yield_with_block_depth'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/instrument.rb:17:in `block in instrument'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/vendor/ruby/heroku-18/lib/ruby/2.6.0/benchmark.rb:308:in `realtime'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/instrument.rb:16:in `instrument'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/base.rb:50:in `instrument'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/base.rb:46:in `instrument'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/rails4.rb:40:in `compile'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/bin/support/ruby_compile:20:in `block (2 levels) in <main>'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/base.rb:190:in `log'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/bin/support/ruby_compile:19:in `block in <main>'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/instrument.rb:35:in `block in trace'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/instrument.rb:18:in `block (2 levels) in instrument'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/instrument.rb:40:in `yield_with_block_depth'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/instrument.rb:17:in `block in instrument'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/vendor/ruby/heroku-18/lib/ruby/2.6.0/benchmark.rb:308:in `realtime'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/instrument.rb:16:in `instrument'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/lib/language_pack/instrument.rb:35:in `trace'
    from /tmp/codon/tmp/buildpacks/50d5eddf222a9b7326028041d4e6509f915ccf2c/bin/support/ruby_compile:15:in `<main>'
 !     Push rejected, failed to compile Ruby app.
 !     Push failed

Bundles, rakes, and starting the app all worked fine locally.

Turns out it was an issue with an update in the ruby buildpack. I locked the buildpack version to an older version with the command heroku buildpacks:set https://github.com/heroku/heroku-buildpack-ruby#v215 -a appname and redeployed. All good after that.

Heroku stack heroku-16 and ruby version 2.3.8

Answer 3

In my case the error was bin/rake file.

    # frozen_string_literal: true
    #!/usr/bin/env ruby
    
    require_relative '../config/boot'
    require 'rake'
    
    Rake.application.run

Heroku requires #!/usr/bin/env ruby on top, like this:

    #!/usr/bin/env ruby
    # frozen_string_literal: true

    require_relative '../config/boot'
    require 'rake'
    
    Rake.application.run

Solved! o/

Answer 4

TL;DR; Have gem "better_errors", gem "binding_of_caller", gem 'pry-byebug' in global scope of your Gemfile

In my case it was because I moved these 3 gems from the global scope to development in my Gemfile:

gem "better_errors"

gem "binding_of_caller"

gem 'pry-byebug'

They should probably be only in the development scope, but there's something that I'm missing. So, moving them back outside of the development scope my deploy and rakes work correctly