Using pry-byebug and not happy with commands behavior? We recommend this project instead

pry-moves

An execution control add-on for Pry.

  • Install: gem 'pry-moves'
  • For non-rails (without auto-require), add to your script: require 'pry-moves'

Commands:

  • n - next line in current frame, including block lines (moving to next line goes as naturally expected)
  • s - step into function execution
    • s func_name - step into first method called by name func_name
  • f - finish execution of current frame (block or method) and stop at next line on higher level
  • c - continue
  • bt - show latest 5 lines from backtrace
    • bt 10 - latest 10 lines
    • bt all - full backtrace
    • bt >foo - write backtrace to file log/backtrace_foo.log
  • up/down/top/bottom - move over call stack
    • up + - move up, including vapid frames (block callers, hidden frames)
    • up pattern - move up till first frame which method name or file position in format folder/script.rb:12 matches regexp pattern
  • debug some_method(param, param2) - call some_method(param, param2) and interactively step into it
  • ! - exit

Examples

To use, 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

Advanced example

Demo class source here

Backtrace and call stack

You can explicitly hide frames from backtrace and call stack by defining hide_from_stack variable:

def insignificant_method
  hide_from_stack = true
  something_insignificant
  yield
end

Configuration

Here is default configuration, you can override it:

PryMoves::Backtrace::lines_count = 5
PryMoves::Backtrace::filter =
  /(\/gems\/|\/rubygems\/|\/bin\/|\/lib\/ruby\/|\/pry-moves\/)/

Threads, helpers

pry-moves can't stop other threads on binding.pry, so they will continue to run. This makes pry-moves not always suitable for debugging of multi-thread projects.

Though you can pause other threads with helper which will suspend execution on current line, until ongoing debug session will be finished with continue:

PryMoves.synchronize_threads

For example, you can put it into function which periodically reports status of thread (if you have such)

Other helpers:

  • PryMoves.open? - if pry input dialog active. Can be used to suppress output from ongoing parallel threads

pry-remote

Rudimentary support for pry-remote (>= 0.1.1) is also included. Ensure pry-remote is loaded or required before pry-moves. For example, in a Gemfile:

gem 'pry'
gem 'pry-remote'
gem 'pry-moves'

Performance

Please note that debugging functionality is implemented through set_trace_func, which imposes certain performance penalty.

Contributors

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

Acknowledgments