find_spec_for_exe': can't find gem bundler (>= 0.a) (Gem::GemNotFoundException)

The problem in my case is that the Gemfile.lock file had a BUNDLED_WITH version of 1.16.1 and gem install bundler installed version 2.0.1, so there was a version mismatch when looking to right the folder

gem install bundler -v 1.16.1 fixed it

Of course, you can also change your Gemfile.lock's BUNDLED_WITH with last bundler version and use recent software, as Sam3000 suggests

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gem update --system

will update the rubygems and will fix the problem.

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Update:

According @noraj's answer and @Niels Kristian's comment, the following command should do the job.

gem update --system
bundle install

I wrote this in case someone gets into an issue like mine.

gem install bundler shows that everythings installs well.

Fetching: bundler-1.16.0.gem (100%)
Successfully installed bundler-1.16.0
Parsing documentation for bundler-1.16.0
Installing ri documentation for bundler-1.16.0
Done installing documentation for bundler after 7 seconds
1 gem installed

When I typed bundle there was an error:

/Users/nikkov/.rvm/gems/ruby-2.4.0/bin/bundle:23:in `load': cannot load such file -- /Users/nikkov/.rvm/rubies/ruby-2.4.0/lib/ruby/gems/2.4.0/gems/bundler-1.16.0/exe/bundle (LoadError)
    from /Users/nikkov/.rvm/gems/ruby-2.4.0/bin/bundle:23:in `<main>'
    from /Users/nikkov/.rvm/gems/ruby-2.4.0/bin/ruby_executable_hooks:15:in `eval'
    from /Users/nikkov/.rvm/gems/ruby-2.4.0/bin/ruby_executable_hooks:15:in `<main>'

And in the folder /Users/nikkov/.rvm/rubies/ruby-2.4.0/lib/ruby/gems/2.4.0/gems/ there wasn't a bundler-1.16.0 folder.

I fixed this with sudo gem install bundler

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This fixed it:

Remove Gemfile.lock rm Gemfile.lock run bundle install again

EDIT: DON'T DO IT IN PRODUCTION!

For production go to this answer: https://stackoverflow.com/posts/54083113/revisions

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The real answer is here if you try to install bundler 2.0.1 or 2.0.0 due to Bundler requiring RubyGems v3.0.0

Yesterday I released Bundler 2.0 that introduced a number of breaking changes. One of the those changes was setting Bundler to require RubyGems v3.0.0. After making the release, it has become clear that lots of our users are running into issues with Bundler 2 requiring a really new version of RubyGems. We have been listening closely to feedback from users and have decided to relax the RubyGems requirement to v2.5.0 at minimum. We have released a new Bundler version, v2.0.1, that adjusts this requirement.

For more info, see: https://bundler.io/blog/2019/01/04/an-update-on-the-bundler-2-release.html

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The reason is your current ruby environment, you got a different version of bundler with the version in Gemfile.lock.

Safe way, install bundler with the same version in Gemfile.lock, this won't break anything if there is some incampatibly thing happened.

Hard way, just remove Gemfile.lock, and run bundle install.

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If you changed the ruby version you're using with rvm use, remove Gemfile.lock and try again.

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to install bundler that matches with your Gemfile.lock use:

gem install bundler -v "$(grep -A 1 "BUNDLED WITH" Gemfile.lock | tail -n 1)"

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Open Gemfile.lock, which is to be found in the root of your app folder. Scroll to the end of the file and see the bundler version used. Then you make sure you install the bundler version used:

gem install bundler -v x.xx.xx

Or - delete the Gemfile.lock and bundle if you have higher bundler version installed.

The choice is yours, my friend.

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Adding to the many answers, my problem stemmed from wanting to use the docker's ruby as a base, but then using rbenv on top. This screws up a lot of things.

I fixed it in this case by:

The Gemfile.lock version did need updating - changing the "BUNDLED WITH" to the latest version did at one point change the error message, so may have been required

in .bash_profile or .bashrc, unsetting the environment variables:

unset GEM_HOME
unset BUNDLE_PATH

After that, rbenv worked fine. Not sure how those env vars were getting loaded in the first place...

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In my case the above suggestions did not work for me. Mine was little different scenario.

When i tried installing bundler using gem install bundler .. But i was getting

ERROR:  While executing gem ... (Gem::FilePermissionError)
    You don't have write permissions for the /Library/Ruby/Gems/2.3.0 directory.

then i tried using sudo gem install bundler then i was getting

ERROR:  While executing gem ... (Gem::FilePermissionError)
  You don't have write permissions for the /usr/bin directory.

then i tried with sudo gem install bundler -n /usr/local/bin ( Just /usr/bin dint work in my case ).

And then successfully installed bundler

EDIT: I use MacOS, maybe /usr/bin din't work for me for that reason (https://stackoverflow.com/a/34989655/3786657 comment )

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I had the same issue today. I solve this problem by removing any PATH in .bashrc for older rvm.

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My problem was I'm using RVM and had the wrong Ruby version activated...

Hope this helps at least one person

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I downgraded ruby from 2.5.x to 2.4.x in my particular case.

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I had to do rake clean --force. Then did gem install rake and so forth.

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