Cannot execute "rails console" due to an error with readline

I cannot execute rails console due to this error:

localhost:TwitterForZombies wiz$ rails c
/Users/wiz/.rbenv/versions/1.9.3-p194/lib/ruby/1.9.1/irb/completion.rb:9:in `require': dlopen(/Users/wiz/.rbenv/versions/1.9.3-p194/lib/ruby/1.9.1/x86_64-darwin12.2.1/readline.bundle, 9): Library not loaded: /usr/local/opt/readline/lib/libreadline.6.2.dylib (LoadError)
  Referenced from: /Users/wiz/.rbenv/versions/1.9.3-p194/lib/ruby/1.9.1/x86_64-darwin12.2.1/readline.bundle
  Reason: image not found - /Users/wiz/.rbenv/versions/1.9.3-p194/lib/ruby/1.9.1/x86_64-darwin12.2.1/readline.bundle
    from /Users/wiz/.rbenv/versions/1.9.3-p194/lib/ruby/1.9.1/irb/completion.rb:9:in `<top (required)>'
    from /Users/wiz/.rbenv/versions/1.9.3-p194/lib/ruby/gems/1.9.1/gems/railties-3.2.9/lib/rails/commands/console.rb:3:in `require'
    from /Users/wiz/.rbenv/versions/1.9.3-p194/lib/ruby/gems/1.9.1/gems/railties-3.2.9/lib/rails/commands/console.rb:3:in `<top (required)>'
    from /Users/wiz/.rbenv/versions/1.9.3-p194/lib/ruby/gems/1.9.1/gems/railties-3.2.9/lib/rails/commands.rb:38:in `require'
    from /Users/wiz/.rbenv/versions/1.9.3-p194/lib/ruby/gems/1.9.1/gems/railties-3.2.9/lib/rails/commands.rb:38:in `<top (required)>'
    from script/rails:6:in `require'
    from script/rails:6:in `<main>'

I have installed readline via homebrew. I'd like to keep using rbenv instead of rvm.

Thank you for reading my question.

Solution 1:

I had the same issue recently with homebrew and libreadline.7.x.dylib / libreadline.6.x.dylib

I solved it by running:

ln -s /usr/local/opt/readline/lib/libreadline.7.0.dylib /usr/local/opt/readline/lib/libreadline.6.dylib

source: https://github.com/rails/rails/issues/26658

Solution 2:

Homebrew is great, but once in a while it doesn't play nice with some of the other moving parts.

A brew update && brew upgrade brought in libreadline.7.x.dylib while automatically removing libreadline.6.x.dylib, which ruby was still relying on.

There may be more clever ways to fix the problem, but brute force worked for me:

$ rbenv uninstall 2.3.1
$ rbenv install 2.3.1
$ cd /path/to/my/app
$ bundle

The above assumes the presence of rbenv's ruby-build and, of course, bundler; replace 2.3.1 with whatever version of ruby you are using.

Please note that similar problems can occur with different homebrew-managed libraries (see my own answer to this, for example)