Cannot start debugger

Hello community,

after upgrading to RubyMine 4.0.1 I cannot start my application in debug mode:

"Error running Development [...] Cannot start debugger. Gem 'ruby-debug-ide' isn't installed or its executable script 'rdebug-ide' doesn't exist."

I'm using Ubuntu 10.04. Here is what gem env says (almost the same as in RubyMine Tools -> Show Gem Environment):

RubyGems Environment:
  - RUBY VERSION: 1.8.7 (2011-04-12 patchlevel 330) [java]
  - INSTALLATION DIRECTORY: /opt/jruby-1.6.1/lib/ruby/gems/1.8
  - RUBY EXECUTABLE: /opt/jruby-1.6.1/bin/jruby
  - EXECUTABLE DIRECTORY: /opt/jruby-1.6.1/bin
    - ruby
    - universal-java-1.6
     - /opt/jruby-1.6.1/lib/ruby/gems/1.8
     - /home/stefmiet/.gem/jruby/1.8
     - :update_sources => true
     - :verbose => true
     - :benchmark => false
     - :backtrace => false
     - :bulk_threshold => 1000
     - "install" => "--no-rdoc --no-ri --env-shebang"
     - "update" => "--no-rdoc --no-ri --env-shebang"

I have ruby-debug-ide installed: gem list -d ruby-debug-ide:

*** LOCAL GEMS ***

ruby-debug-ide (0.4.16)
    Author: Markus Barchfeld, Martin Krauskopf, Mark Moseley, JetBrains
    RubyMine Team
    Installed at: /opt/jruby-1.6.1/lib/ruby/gems/1.8

    IDE interface for ruby-debug.

I also see the executable script in the following path:


So I do not know where RubyMine is searching the gem and it's executable ... everything seems to be correctly installed. Any advice?


Hello Stefan,

please try updating to the latest ruby-debug-ide version by running
gem install ruby-debug-ide --pre


Hi Dennis,

I did the update:

Building native extensions.  This could take a while...
Successfully installed ruby-debug-ide-0.4.17.beta8
1 gem installed

But unfortunately RubyMine 4.0.1 is still not debugging. If I start the old version of RubyMine 3.2.4 it is still okay. Also with the updated gem:

Fast Debugger (ruby-debug-ide 0.4.17.beta8, ruby-debug-base listens on
=> Booting WEBrick
=> Rails 3.0.7 application starting in development on
=> Call with -d to detach
=> Ctrl-C to shutdown server
[2012-03-02 12:58:55] INFO  WEBrick 1.3.1
[2012-03-02 12:58:55] INFO  ruby 1.8.7 (2011-04-12) [java]
[2012-03-02 12:59:00] INFO  WEBrick::HTTPServer#start: pid=6783 port=3000

I imported all settings from the old installation ... what could be the difference?


Oh, it seems that latest ruby-debug-base gem requires linecache gem and it's presence is incorrectly checked for all versions. You can install linecache gem and debug should work fine


Great job, Dennis. Now it works! :)

But I would be interested in how you figured it out? I did't see any hint in this direction ...


I am seeing this problem with RubyMine 8. I attempted to install the linecache gem, but got errors .

lvachon$ gem install linecache
Fetching: linecache-1.3.1.gem (100%)
Building native extensions. This could take a while...
ERROR: Error installing linecache:
ERROR: Failed to build gem native extension.

current directory: /Users/lvachon/.rvm/rubies/ruby-2.1.6/lib/ruby/gems/2.1.0/gems/linecache-1.3.1/ext/linecache
/Users/lvachon/.rvm/rubies/ruby-2.1.6/bin/ruby -r ./siteconf20160225-899-1h5axoo.rb extconf.rb
Can't handle 1.9.x yet
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of necessary
libraries and/or headers. Check the mkmf.log file for more details. You may
need configuration options.

Provided configuration options:

extconf failed, exit code 1

Gem files will remain installed in /Users/lvachon/.rvm/rubies/ruby-2.1.6/lib/ruby/gems/2.1.0/gems/linecache-1.3.1 for inspection.
Results logged to /Users/lvachon/.rvm/rubies/ruby-2.1.6/lib/ruby/gems/2.1.0/extensions/x86_64-darwin-14/2.1.0-static/linecache-1.3.1/gem_make.out


@Laura, what problem are you experiencing? You don't need to install line cache gem for 2+


Please try doing:

gem install ruby-debug-ide --pre


gem installs without error. still getting the same Error message when attempting to run the debugger


Laura, could you please specify what you're debugging (a screenshot of Run configuration would be also great)


I fixed this problem by removing all my gems. removing ruby. cleaning up directories and rvm. removing ruby mine, then reinstalling everything. Was a pain, but it worked.


Having the same issue as Laura. Can't install the `ruby-debug-ide` gem isn't installed or its executable script does not exist.
I have the latest version of RubyMine (I just installed it). So what's the suggested approach to solving this issue? 


About error when debugging using Rubymine:

Good afternoon my friends

Who can help

I'm trying to debug an application using Rubymine but an error is being generated

As per images

The IDE starts the application, until I show the return in chrome

The problem is that the error is being returned when trying to debug the application

Error running 'foreman start': Cannot start debugger. Gem 'ruby-debug-ide' isn't installed or its executable script 'rdebug-ide' doesn't exist.

Can anyone help?


Sorry for not getting back to you sooner. Could you please check if there're any problems in the latest RubyMine 2021.3.1 because I didn't manage to reproduce it there.


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