I just updated to Ruby 1.9.3p0 and Rails 3.1.1. Now when I try to launch the server, it complains that I should install ruby-debug, even though it's already installed.
% rails server --environment=development --debug
=> Booting WEBrick
=> Rails 3.1.0 application starting in development on http://0.0.0.0:3000
=> Call with -d to detach
=> Ctrl-C to shutdown server
You need to install ruby-debug to run the server in debugging mode. With gems, use 'gem install ruby-debug'
Exiting
In my Gemfile I have
# see: http://stackoverflow.com/questions/1083451/debugging-in-ruby-1-9
gem 'ruby-debug-base19', "0.11.24"
gem 'ruby-debug19', "0.11.6"
Is it possible to run debug with the latest version of Ruby?
Update (April 28, 2012)
Try the new debugger gem as a replacement for ruby-debug.
(credit to #ryanb)
Update (March 2, 2012)
Installation of linecache19 and ruby-debug-base19 can be easily done with:
bash < <(curl -L https://raw.github.com/gist/1333785)
(credit to #fredostarr)
Original answer
Have you looked at ruby-debug19 on ruby-1.9.3-preview1?
Here's a temporary solution:
http://blog.wyeworks.com/2011/11/1/ruby-1-9-3-and-ruby-debug
Excerpt from the site:
First download linecache19-0.5.13.gem and
ruby-debug-base19-0.11.26.gem from
http://rubyforge.org/frs/?group_id=8883, then …
$ gem install linecache19-0.5.13.gem
Building native extensions. This could take a while...
Successfully installed linecache19-0.5.13
1 gem installed
$ gem install ruby-debug-base19-0.11.26.gem -- --with-ruby-include=/Users/santiago/.rbenv/source/ruby-1.9.3-p0
Building native extensions. This could take a while...
Successfully installed ruby-debug-base19-0.11.26
1 gem installed
$ irb
irb(main):001:0> require 'ruby-debug'
=> true
Installation of linecache19 and ruby-debug-base19 can be easily done with:
bash < <(curl -L https://raw.github.com/gist/1333785)
Someone else posted in a comment to try Pry, which is what I did. This is what's necessary for Rails:
# Gemfile
gem 'pry-rails'
# In your Rails Project where you want a 'debugger'
puts 'i want to insert some code between this'
binding.pry
puts 'and this'
Immediately after installing I notice my .irbrc doesn't load, so I don't get pretty console output. I also added this to my '~/.pryrc'
# setting up pry to have irb helpers like reload!
if defined?(Rails) && Rails.env
extend Rails::ConsoleMethods
end
Pry has some nice features that I've wanted to check out, and I may yet return to ruby-debug once there's a simple way to integrate it into a Rails project for Ruby 1.9.3. I can run the curl command from the other answers, but this is something I'll have to point my teammates to for our Rails project, so it doesn't scale well IMO.
Maybe not the definitive answer to this question, but I was lead here by a chain of closed duplicates.
For me the problem was that I run a project in both ruby 1.8 and ruby 1.9, and my Gemfile needed this change:
gem 'debugger', :require => 'ruby-debug', :platforms => :mri_19
gem 'ruby-debug', :platforms => :mri_18
Now it works for both rubies.
For more info see here: http://gembundler.com/man/gemfile.5.html#PLATFORMS-platforms-
For Windows Users:
First Download :linecache19-0.5.13.gem and ruby-debug-base19-0.11.26.gem
From : http://rubyforge.org/frs/?group_id=8883&release_id=46303
Assumption: Ruby is in c:\Ruby1.93
put the gem files downloaded to c:\temp
(linecache19-0.5.13.gem and ruby-debug-base19-0.11.26.gem)
then execute from command line:
gem install c:\temp\linecache19-0.5.13.gem
gem install c:\temp\ruby-debug-base19-0.11.26.gem -- --with-ruby-include=C:\Ruby1.93\include\ruby-1.9.1\ruby-1.9.3-p0
BTW, if you use the newest patch for ruby1.9.3 (falcon, https://gist.github.com/1688857), use following commands
wget http://rubyforge.org/frs/download.php/75414/linecache19-0.5.13.gem
wget http://rubyforge.org/frs/download.php/75415/ruby-debug-base19-0.11.26.gem
gem install linecache19-0.5.13.gem
## with rvm:
gem install ruby-debug-base19-0.11.26.gem -- --with-ruby-include=$HOME/.rvm/src/ruby-1.9.3-p0-falcon
## with rbenv (this is a guess):
gem install ruby-debug-base19-0.11.26.gem -- --with-ruby-include=$HOME/.rbenv/source/ruby-1.9.3-p0-falcon
See my answer here :
Ruby-debug not working - Stack Overflow
It's about getting Ruby debugging to work with the following setup
Mac OS X Lion 10.7.2
Aptana Studio 3 (Build 3.0.8.201201201658)
Using rvm, in my project working directory I have a .rvmrc stating:
rvm use ruby-1.9.3-p0#mygemset
Basically, I had to use :
linecache19 (0.5.13)
ruby-debug-base19x (0.11.30.pre10)
ruby-debug-ide (0.4.16)
Note that I'm not using ruby-debug-base19 but ruby-debug-base19x
I hope this helps!
-- Freddy
Also you need to check if the gem 'ruby_source_code' is already installed.
Check: http://bugs.ruby-lang.org/issues/1857#note-8
If you don't have rvm and assuming you ruby installation is in /usr/local/ruby-1.9.3-po your can use this command:
curl -L https://raw.github.com/gist/1533750 | sudo /bin/bash
Related
I upgraded my environment from Ruby 2.0.0 to 2.2.3.
I also upgraded (overwrite) DevKit, and re-run ruby dk.rb install.
I removed Gemfile.lock and ran bundle install to start with a brand new environment. Everything looks ok, but I get the error:
E:\Projects\development\Stairs>rake db:migrate
rake aborted!
LoadError: cannot load such file -- bcrypt_ext
E:/Projects/development/Stairs/config/application.rb:7:in `<top (required)>'
E:/Projects/development/Stairs/Rakefile:4:in `<top (required)>'
LoadError: cannot load such file -- 2.2/bcrypt_ext
E:/Projects/development/Stairs/config/application.rb:7:in `<top (required)>'
E:/Projects/development/Stairs/Rakefile:4:in `<top (required)>'
(See full trace by running task with --trace)
I first had the same issue with Nokogiri, which I solved using this solution : Nokogiri load error
using Juloi Elixir's solution and installing Nokogiri from a local copy.
But I don't feel like doing this foreach gem! It looks like ruby is searching the gem using a ./ or ./2.2 path, while gems are stored in a ./2.2.0 path. Is this configurable?
How can I solve this issue?
Note: Gemfile contains gem 'bcrypt', '~> 3.1.10'
Thanks!
I spent an entire hour fixing this, just now.
Well what I did was I followed some advice online to do a
gem install bcrypt --platform=ruby
And then, it worked in irb.
irb(main):001:0> require 'bcrypt'
=> true
Later when I had to do a bundle install, for some odd reason rails installed another bcrypt and the error was back. So I had two folders in my gem root.
bcrypt-3.1.10
bcrypt-3.1.10-x64-mingw32
So, since the first folder was the one that got built with the devkit, and it works. I deleted the contents of the second folder and copied the contents of the first into it.
Seems to be working as I'm writing this.
Solution was here: bcrypt-ruby#github:
Rebuild locally the bcrypt gem:
Change to the gem directory \Ruby22-x64\lib\ruby\gems\2.2.0\gems\bcrypt-3.1.10-x64-mingw32\ext\mri>
Run ruby extconf.rb
Run make
Run make install
Note that this works only if your DevKit environment is correctly setup (run devkitvars.bat).
#user1185081 's solution worked for me in a windows machine. I ran following commands and worked like magic:
$ cd C:\RailsInstaller\Ruby2.2.0\lib\ruby\gems\2.2.0\gems\bcrypt-3.1.10-x86-mingw32\ext\mri
$ ruby extconf.rb
$ C:\<DevKit Path>\devkitvars.bat (assuming you have devkit installed)(Ran this instead of running "make" because it was not recognized as an internal or external command)
$ make install
What worked for me on Windows 7:
gem uninstall bcrypt to uninstall all versions of bcrypt, including those listed as dependencies
gem install bcrypt to reinstall
bundle install
In my case, a designating of the old version to bcrypt in Gemfile was a cause of the error. I removed a designating of the version and run bundle update bcrypt, then it was settled.
Here is the solution worked for me:
C:\> gem uninstall brcypt
C:\> gem install --no-ri --no-rdoc bcrypt
C:\> cd (path to gems root)\bcrypt-3.1.7-x86-mingw32\ext\mri
C:\(path to gems root)\bcrypt-3.1.7-x86-mingw32\ext\mri> ruby extconf.rb
C:\(path to gems root)\bcrypt-3.1.7-x86-mingw32\ext\mri> make
C:\(path to gems root)\bcrypt-3.1.7-x86-mingw32\ext\mri> make install
I had the same problem:
cannot load such file — bcrypt_ext
Windows 8.1 64bit
ruby 2.3.3p222 (2016-11-21 revision 56859) [i386-mingw32]
Rails 5.1.4
My solution:
gem uninstall bcrypt-ruby
gem uninstall bcrypt
gem install bcrypt –platform=ruby
added this whole line to Gemfile:
gem 'bcrypt', git: 'https://github.com/codahale/bcrypt-ruby.git', :require => 'bcrypt'
bundle install
This works for me, add this to your gems file:
gem 'bcrypt', '~> 3.1.7', platform: :ruby
This process is for windows:
The problem is with the programs installed on the system.
Uninstall all rails programs:
All Ruby programs.
RailsInstaller.
Removes all files that have been able to uninstall, you have to do it manually inside:
C:\RailsInstaller
Install de ruby version 2.2 from:
http://railsinstaller.org/en
Wait a moment and it's already to go.
MarlonJon.es
I've been breaking my head over this error for hours now, and still haven't found a fix. When I run sidekiq using sudo -u root -H RAILS_ENV=production script/background_jobs start I'm getting this error in the sidekiq.log:
Gemfile syntax error:
/home/website/git/gitlab/Gemfile:20: syntax error, unexpected ':', expecting $end
gem "mysql2", group: :mysql
I've installed Ruby 2.1.0 and am running CentOS. I've seen other posts with this error, and their problem was that they were running Ruby 1.8, however, I'm running Ruby 2.1.0 and also getting this error.
Any help is greatly appreciated.
EDIT: My gemfile http://pastebin.com/T5z4GZ3a
bundle returns
Your bundle is complete!
Gems in the groups development, test, postgres, puma and aws were not installed.
It was installed into ./vendor/bundle
EDIT2: My background_jobs script http://pastebin.com/kdicTFqk
bundle show bundler returns
2.1.0
/usr/local/rvm/gems/ruby-2.1.0#global/gems/bundler-1.5.2
EDIT3: I think I have found the problem, not sure how to solve it though. I added p RUBY_VERSION as first line of my Gemfile, then I changed every line written like this: group: :mysql to this :group => :mysql (because that is working on older versions).
However, when I run Sidekiq now, this shows up in the sidekiq.log:
"1.8.7"
bundler: command not found: sidekiq
Install missing gem executables with `bundle install`
I am really, really confused now. Here it clearly says my Ruby version is 1.8.7, but that's not right. ruby -v or rvm list rubies only show that Ruby 2.1.0 is installed, and set as default.
Make sure, that when you issue bundle install you have picked up the ruby 2.1.0, just do as follows:
Enter into app's folder, then edit the Gemfile to a few lines, inserting into it p RUBY_VERSION
Issue bundle install, and see the ruby version output, it shell be 2.1.0, and the form of gem "mysql2", group: :mysql should work.
2.1.0
Then add line one-by-one, or group-by-group, issuing the bundle install
So make sure that the Gemfile will be fully restored at the end.
Then you should do a proper setup shell environment in your run script. So if you use the rvm just replace the first line with:
#!/bin/bash -l
Add sourcing to rvm:
source "$HOME/.rvm/scripts/rvm"
Before starting the script, add shell command to set proper version of ruby to 2.1.0
rvm use ruby-2.1.0#global
NOTE: Probably you have to use an other gemset not the global one.
I just installed RVM, Ruby, Rails etc. on my virtual ubuntu 12.04 32bit running in a virtualbox. Now I encounter the problem that for my first rails project bundle install or bundle update takes very long time. Even when I create a new project with rails (which includes bundle install).
I use only the standard gems:
source 'https://rubygems.org'
gem 'rails', '3.2.12'
# Bundle edge Rails instead:
# gem 'rails', :git => 'git://github.com/rails/rails.git'
group :development do
gem 'sqlite3', '1.3.5'
end
# Gems used only for assets and not required
# in production environments by default.
group :assets do
gem 'sass-rails', '3.2.5'
gem 'coffee-rails', '3.2.2'
# See https://github.com/sstephenson/execjs#readme for more supported runtimes
# gem 'therubyracer', :platforms => :ruby
gem 'uglifier', '1.2.3'
end
gem 'jquery-rails', '2.0.2'
I tried bundle install without any gems but gem 'rails', '3.2.12'. After that I typed again bundle install with all gems in my gemfile. It took me 10 minutes to check for dependencies. The output of --verbose is a mix of HTTP success and HTTP redirection.
Rails version: Rails 3.2.12
Ruby version: ruby 1.9.3p392 (2013-02-22 revision 39386)
Rvm: rvm 1.18.18
bundle version: Bundler version 1.3.2
I already searched fot a solution, but nothing helped.
I want to warn: There is a security purpose for using https over http. Try at first the other answers mentioned in this thread.
Changing https to http in my Gemfile did the magic. Before I have to create the project with rails new APP --skip-bundle
Bundler just got an update of parallel processing of gems.
gem install bundler --pre
will solve the problem in the best possible way for now.
Source
You can also use multiple jobs, it may improve a little bit
bundle install --jobs 8
Here is a tutorial about it
Bundler v1.12.x was released in 2016 and caused some users to experience slow bundle install issues.
In this instance staying with v1.11.2 is the best option (it's fast) until a fix is released.
It's worth heading over to Rubygems.org to try different versions of the bundler gem.
Check existing bundler versions, uninstall existing version, install version 1.11.2 example:
gem list | grep bundler
gem uninstall bundler -v existing-version-number
gem install bundler -v 1.11.2
A developer friendly method is to override the gem server with a faster alternative.
In our case, we can configure http as a mirror to address slow https connections:
bundle config mirror.https://rubygems.org http://rubygems.org
This allows you to keep original Gemfile configuration while still using faster http connections to fetch gems.
If you wanted to switch back to https:
bundle config --delete mirror.https://rubygems.org
bundle config has a default --global option. You can specify --local to limit configurations to local application folder.
Configuration is saved into global ~/.bundle/config and local .bundle/config.
If you're still seeing this issue with Bundler 1.12.5, you may want to try updating the OpenSSL used by your Ruby.
For me this went like so:
pmorse$ bundle --version
Bundler version 1.12.5
pmorse$ ruby -ropenssl -e 'puts OpenSSL::OPENSSL_VERSION'
OpenSSL 1.0.1j 15 Oct 2014
pmorse$ openssl version
OpenSSL 0.9.8zg 14 July 2015
pmorse$ brew info openssl
openssl: stable 1.0.2h (bottled) [keg-only]
[... more brew output ...]
pmorse$ rvm reinstall ruby-2.2.2 --with-openssl-dir=`brew --prefix openssl`
[... lots of rvm output ...]
pmorse$ ruby -ropenssl -e 'puts OpenSSL::OPENSSL_VERSION'
OpenSSL 1.0.2h 3 May 2016
This should make bundle quicker again without requiring you to go from https to http.
I know this may be basic answer but try to install developer tools from the main Ruby site. I have had a similar problem and it did work. Sometimes simple solutions are the best!
Good luck!
I have standard ruby-head and Rails 3.1rc4.
I installed ruby-debug with following instructions from http://dirk.net/2010/04/17/ruby-debug-with-ruby-19x-and-rails-3-on-rvm/
But when i run rails s --debugger it will throw this strange error
/Users/schovi/.rvm/gems/ruby-head/gems/activesupport-3.1.0.rc4/lib/active_support/dependencies.rb:237:in `require': dlopen(/Users/schovi/.rvm/gems/ruby-head/gems/linecache19-0.5.12/lib/trace_nums19.bundle, 9): Symbol not found: _ruby_current_thread (LoadError)
Referenced from: /Users/schovi/.rvm/gems/ruby-head/gems/linecache19-0.5.12/lib/trace_nums19.bundle
Expected in: flat namespace
in /Users/schovi/.rvm/gems/ruby-head/gems/linecache19-0.5.12/lib/trace_nums19.bundle - /Users/schovi/.rvm/gems/ruby-head/gems/linecache19-0.5.12/lib/trace_nums19.bundle
from /Users/schovi/.rvm/gems/ruby-head/gems/activesupport-3.1.0.rc4/lib/active_support/dependencies.rb:237:in `block in require'
from /Users/schovi/.rvm/gems/ruby-head/gems/activesupport-3.1.0.rc4/lib/active_support/dependencies.rb:223:in `block in load_dependency'
Any idea?
Thanks, David
UPDATE:
Looks like you only need to put this in your gemfile:
gem "debugger"
and now works.
Old article follows
====================================
Jerome is correct, but lacking in the details. Here is the blow by blow, taken from this https://gist.github.com/1331533, in particular thanks to andrewroth's post. I've tested this as of the time of this post. One hopes that the changes will be deployed somewhere standard soon.
Installing ruby debugger on ruby 1.9.3-p125:
export PATCH_LEVEL=`ruby -e 'puts RUBY_PATCHLEVEL'`
export RVM_SRC=$HOME/.rvm/rubies/ruby-1.9.3-p$PATCH_LEVEL/include/ruby-1.9.1
gem install archive-tar-minitar
gem install ruby_core_source -- --with-ruby-include=/$RVM_SRC
export RVM_SRC=$HOME/.rvm/rubies/ruby-1.9.3-p$PATCH_LEVEL/include/ruby-1.9.1/ruby-1.9.3-p$PATCH_LEVEL
wget http://rubyforge.org/frs/download.php/75415/ruby-debug-base19-0.11.26.gem
wget http://rubyforge.org/frs/download.php/63094/ruby-debug19-0.11.6.gem
wget http://rubyforge.org/frs/download.php/75414/linecache19-0.5.13.gem
gem install linecache19-0.5.13.gem -- --with-ruby-include=/$RVM_SRC
# if that step failed, and you are running OSX Lion, then following this post can help you:
# http://stackoverflow.com/questions/8032824/cant-install-ruby-under-lion-with-rvm-gcc-issues
# this happens if you recently installed xcode from the app store.
# bizarrely, for me I had to do this: ln -s /usr/bin/gcc /usr/bin/gcc-4.2
gem install ruby-debug-base19-0.11.26.gem -- --with-ruby-include=/$RVM_SRC
Then edit Gemfile:
gem 'linecache19', '0.5.13', :path => "~/.rvm/gems/ruby-1.9.3-p#{RUBY_PATCHLEVEL}/gems/linecache19-0.5.13/"
gem 'ruby-debug-base19', '0.11.26', :path => "~/.rvm/gems/ruby-1.9.3-p#{RUBY_PATCHLEVEL}/gems/ruby-debug-base19-0.11.26/"
gem 'ruby-debug19', :require => 'ruby-debug'
Then install:
bundle install
I used the gem 'debugger' which is a fork of ruby-debug(19) that works on 1.9.2 and 1.9.3 and installs easily for rvm/rbenv rubies.
It makes the error disappear !
It looks like this is a known bug in ruby-debug-base, for the moment. I have added my comment to the issue on the bug tracker. Plase consider adding your notes as well:
http://rubyforge.org/tracker/index.php?func=detail&aid=29222&group_id=8883&atid=34290
In the meantime, ruby 1.9 has a built-in debugger; its just very slow. Manually add this require line to your code:
require 'debug'
Also, the debugger breaks on all StandardError exceptions by default, so do this when it first starts up:
catch off
If you are running Ruby 1.9.3x, to fix it go to ruby-debug on rubyforge, download and install ruby-debug-base 0.11.26 and linecache19 0.5.13. Modify your Gemfile to use these files, then run
bundle update ruby-debug-base19
Debugger should work now.
Thanks
Jerome
This was fixed upgrading to the latest gems of all debug
Using ruby 1.9.3, I was able to get this to work by adding the gem 'ruby-debug-base19x' (note the 'x' at the end of the name) in addition to 'ruby-debug19'.
My system is rvm 1.18.10 and ruby 1.9.3p392 on Mac OSX 10.8.5. I first installed gem 'ruby-debug19', but for the well-known reason, the debugger did not work.
I then ran
local$ gem install 'debugger'
as suggested by many other posts. The gem was installed successfully with the following outputs:
local$ gem install debugger
Fetching: debugger-ruby_core_source-1.2.3.gem (100%)
Fetching: debugger-linecache-1.2.0.gem (100%)
Fetching: debugger-1.6.2.gem (100%)
Building native extensions. This could take a while...
Successfully installed debugger-ruby_core_source-1.2.3
Successfully installed debugger-linecache-1.2.0
Successfully installed debugger-1.6.2
3 gems installed
Installing ri documentation for debugger-ruby_core_source-1.2.3...
Installing ri documentation for debugger-linecache-1.2.0...
Installing ri documentation for debugger-1.6.2...
Installing RDoc documentation for debugger-ruby_core_source-1.2.3...
Installing RDoc documentation for debugger-linecache-1.2.0...
Installing RDoc documentation for debugger-1.6.2...
local$ irb
1.9.3-p392 :002 > require 'debugger'
=> true
I then ran
local$ rails server --debug
/usr/local/rvm/gems/ruby-1.9.3-p392/gems/activesupport-3.2.11/lib/active_support/dependencies.rb:251:
in`require': dlopen(/usr/local/rvm/gems/ruby-1.9.3-p392/gems/ruby-debug-base19-0.11.25/lib/ruby_debug.bundle,
9): Symbol not found: _ruby_current_thread (LoadError)
Referenced from: /usr/local/rvm/gems/ruby-1.9.3-p392/gems/ruby-debug-base19-0.11.25/lib/ruby_debug.bundle
Expected in: flat namespace
in /usr/local/rvm/gems/ruby-1.9.3-p392/gems/ruby-debug-base19-0.11.25/lib/ruby_debug.bundle - /usr/local/rvm/gems/ruby-1.9.3-p392/gems/ruby-debug-base19-0.11.25/lib/ruby_debug.bundle
......
I resolved this error by commenting out the line "gem 'ruby-debug19'" and adding a new line "gem 'debugger'" in the Gemfile, and then ran
local$ bundle update
After that, everything worked fine.
local$ rails server --debug
=> Booting WEBrick
=> Rails 3.2.14 application starting in development on http://0.0.0.0:3000
=> Call with -d to detach
=> Ctrl-C to shutdown server
=> Debugger enabled
[2013-10-15 12:50:21] INFO WEBrick 1.3.1
[2013-10-15 12:50:21] INFO ruby 1.9.3 (2013-02-22) [x86_64-darwin10.8.0]
[2013-10-15 12:50:21] INFO WEBrick::HTTPServer#start: pid=7206 port=3000
I installer ruby-debugger but even after that , when I try to start the rails server with "--debugger" option I get a console error saying that ruby-debugger is not installed see the logs below :-
:~/work_space/rails_apps/Bidding_sys_remaining$ sudo gem install ruby-debug <<<<<<<
Building native extensions. This could take a while...
Building native extensions. This could take a while...
Successfully installed columnize-0.3.2
Successfully installed linecache-0.43
Successfully installed ruby-debug-base-0.10.4
Successfully installed ruby-debug-0.10.4
4 gems installed
Installing ri documentation for columnize-0.3.2...
Installing ri documentation for linecache-0.43...
Installing ri documentation for ruby-debug-base-0.10.4...
Installing ri documentation for ruby-debug-0.10.4...
Installing RDoc documentation for columnize-0.3.2...
Installing RDoc documentation for linecache-0.43...
Installing RDoc documentation for ruby-debug-base-0.10.4...
Installing RDoc documentation for ruby-debug-0.10.4...
:~/work_space/rails_apps/Bidding_sys_remaining$
:~/work_space/rails_apps/Bidding_sys_remaining$ rails server --debugger
=> Booting WEBrick
=> Rails 3.0.1 application starting in development on http://0.0.0.0:3000
=> Call with -d to detach
=> Ctrl-C to shutdown server
You need to install ruby-debug to run the server in debugging mode. With gems, use 'gem install ruby-debug'
Exiting
This is the first time I'm trying to use the rails debugger.
Also any suggestions for links, to get help for getting started with rails debugger any guides for newbies ??
Make sure you include the gem in the Gemfile
gem 'ruby-debug' # for ruby 1.8.7+
gem 'ruby-debug19' # for ruby 1.9.2+
and then run bundle install
Update:
You can also add this to your Gemfile and it will take care of both ruby versions.
gem 'ruby-debug19', :require => 'ruby-debug', :platforms => :mri_19
gem 'ruby-debug', :platforms => :mri_18
Just to hop on to what George said, since the Gemfile supports it, you might want to put it in a group, since you likely don't want ruby-debug in production.
group :development do
gem 'ruby-debug19' # or ruby-debug for 1.8.7
end