pry-debugger

Fast execution control in Pry

Adds step, next, finish, and continue commands and breakpoints to Pry using debugger.

To use, invoke pry normally. No need to start your script or app differently.

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

For a complete debugging environment, add pry-stack_explorer for call-stack frame navigation.

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. Also takes an optional numeric argument to step multiple lines.

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.

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.

Type break --help from a Pry session to see all available options.

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

Caveats

pry-debugger is not yet thread-safe, so only use in single-threaded environments.

Only supports MRI 1.9.2 and 1.9.3. For a pure ruby approach not reliant on debugger, check out pry-nav. Note: pry-nav and pry-debugger cannot be loaded together.

Remote debugging

Support for pry-remote (>= 0.1.4) is also included. Requires explicity requiring pry-debugger, 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-stack_explorer'
gem 'pry-debugger'

Then add binding.remote_pry where you want to pause:

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

Using Pry with Rails? Check out Jazz Hands.

Tips

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

Pry.commands.alias_command 'c', 'continue'
Pry.commands.alias_command 's', 'step'
Pry.commands.alias_command 'n', 'next'
Pry.commands.alias_command 'f', 'finish'

Contributions

Patches and bug reports are welcome. Just send a pull request or file an issue. Project changelog.