pry-debugger-jruby

JRuby 9k-compatible pry debugging!

Requires JRuby >= 9.1.3.0.

Using MRI? I strongly recommend pry-byebug instead!

Adds step, next, finish, and continue commands and breakpoints (break/breakpoints) to Pry.

To use:

• run JRuby with the --debug flag
• load the gem with require 'pry-debugger-jruby' (auto-loading was unfortunately removed in Pry 0.14)
• and then invoke pry normally:

  def some_method
    binding.pry          # Execution will stop here.
    puts 'Hello, World!' # Run 'step' or 'next' in the console to move here.
  end

You can also add the --debug flag to your JRUBY_OPTS environment variable, so it will be picked up by any ruby application. Do note that running JRuby in debug mode does have a noticeable impact on performance.

Execution Commands

• step: Step execution into the next line or method. Takes an optional numeric argument to step multiple times.

• next: Step over to the next line within the same frame. Takes an optional numeric argument to step multiple times. Differs from step in that it always stays within the same frame (e.g. does not go into other method calls).

• finish: Execute until current stack frame returns.

• continue: Continue program execution and end the Pry session.

Breakpoints

You can set and adjust breakpoints directly from a Pry session using the following commands:

• break: Set a new breakpoint from a line number in the current file, a file and line number, or a method. Pass an optional expression to create a conditional breakpoint. Edit existing breakpoints via various flags. Type break --help from a Pry session to see all available options.

  Examples:

break SomeClass#run            Break at the start of `SomeClass#run`.
break Foo#bar if baz?          Break at `Foo#bar` only if `baz?`.
break app/models/user.rb:15    Break at line 15 in user.rb.
break 14                       Break at line 14 in the current file.

break --condition 4 x > 2      Change condition on breakpoint #4 to 'x > 2'.
break --condition 3            Remove the condition on breakpoint #3.

break --delete 5               Delete breakpoint #5.
break --disable-all            Disable all breakpoints.

break                          List all breakpoints. (Same as `breakpoints`)
break --show 2                 Show details about breakpoint #2.

• breakpoints: List all defined breakpoints. Pass -v or --verbose to see the source code around each breakpoint.

Remote debugging

Support for pry-remote is also included. Requires explicity requiring pry-debugger-jruby, not just relying on pry's plugin loader.

Want to debug a Rails app running inside foreman? Add to your Gemfile:

gem 'pry'
gem 'pry-remote'
gem 'pry-debugger-jruby'

Then add binding.remote_pry where you want to pause:

require 'pry-remote'

class UsersController < ApplicationController
  def index
    binding.remote_pry
    # ...
  end
end

Load a page that triggers the code. Connect to the session:

$ bundle exec pry-remote

Tips

Stepping through code often? Add the following shortcuts to ~/.pryrc:

if defined?(PryDebuggerJRuby)
  Pry.commands.alias_command 'c', 'continue'
  Pry.commands.alias_command 's', 'step'
  Pry.commands.alias_command 'n', 'next'
  Pry.commands.alias_command 'f', 'finish'
end

Contributors

pry-debugger-jruby is maintained by Ivo Anjo and is based off the awesome previous work from the pry-debugger creators:

• Gopal Patel
• John Mair
• Nicolas Viennot
• Benjamin R. Haskell
• Joshua Hou
• ...and others who helped with pry-nav

Patches and bug reports are welcome. Just send in a pull request or issue :)