Debugging in Ruby 2
yui-knk and deivid-rodriguez Make `program_with_two_breakpoints` has exactly 2 breakpoints (#517)
This test case was introduced as a regression test of
#274
in #406.

The description of issues/274 says an exception will be raised
if the byebug CLI is terminated when main program is sleeping.

Before this commit there are 2 breakpoints (`byebug` method call)
before `sleep 3` and `"cont"` is called once because the arugment of
`remote_debug_connect_and_interrupt` is `"cont"`.
I think this is not intended.

And the method name of test case is `program_with_two_breakpoints`,
on the other hand the program had 3 breakpoints (`byebug`).
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README.md

Byebug

Version Tidelift Coverage Gitter

Byebug is a simple to use and feature rich debugger for Ruby. It uses the TracePoint API for execution control and the Debug Inspector API for call stack navigation. Therefore, Byebug doesn't depend on internal core sources. Byebug is also fast because it is developed as a C extension and reliable because it is supported by a full test suite.

The debugger permits the ability to understand what is going on inside a Ruby program while it executes and offers many of the traditional debugging features such as:

  • Stepping: Running your program one line at a time.
  • Breaking: Pausing the program at some event or specified instruction, to examine the current state.
  • Evaluating: Basic REPL functionality, although pry does a better job at that.
  • Tracking: Keeping track of the different values of your variables or the different lines executed by your program.

Build Status

Linux Cir Windows Vey

Requirements

MRI 2.3.0 or higher.

Install

gem install byebug

Alternatively, if you use bundler:

bundle add byebug --group "development, test"

Usage

From within the Ruby code

Simply include byebug wherever you want to start debugging and the execution will stop there. For example, if you were debugging Rails, you would add byebug to your code:

def index
  byebug
  @articles = Article.find_recent
end

And then start a Rails server:

bin/rails s

Once the execution gets to your byebug command, you will receive a debugging prompt.

From the command line

If you want to debug a Ruby script without editing it, you can invoke byebug from the command line.

byebug myscript.rb

Byebug's commands

Command Aliases Subcommands
backtrace bt where
break
catch
condition
continue
debug
delete
disable breakpoints display
display
down
edit
enable breakpoints display
finish
frame
help
history
info args breakpoints catch display file line program
interrupt
irb
kill
list
method instance
next
pry
quit
restart
save
set autoirb autolist autopry autosave basename callstyle fullpath histfile histsize linetrace listsize post_mortem savefile stack_on_error width
show autoirb autolist autopry autosave basename callstyle fullpath histfile histsize linetrace listsize post_mortem savefile stack_on_error width
source
step
thread current list resume stop switch
tracevar
undisplay
untracevar
up
var all constant global instance local

Semantic Versioning

Byebug attempts to follow semantic versioning and bump major version only when backwards incompatible changes are released. Backwards compatibility is targeted to pry-byebug and any other plugins relying on byebug.

Getting Started

Read byebug's markdown guide to get started. Proper documentation will be eventually written.

Related projects

  • pry-byebug adds next, step, finish, continue and break commands to pry using byebug.
  • ruby-debug-passenger adds a rake task that restarts Passenger with Byebug connected.
  • minitest-byebug starts a byebug session on minitest failures.
  • sublime_debugger provides a plugin for ruby debugging on Sublime Text.
  • atom-byebug provides integration with the Atom editor [EXPERIMENTAL].

Contribute

See Getting Started with Development.

Funding

Subscribe to tidelift to ensure byebug stays actively maintained, and at the same time get licensing assurances and timely security notifications for your open source dependencies.

You can also help byebug by leaving a small (or big) tip through Liberapay.

Credits

Everybody who has ever contributed to this forked and reforked piece of software, especially:

  • @ko1, author of the awesome TracePoint API for Ruby.
  • @cldwalker, debugger's maintainer.
  • @denofevil, author of debase, the starting point of this.
  • @kevjames3 for testing, bug reports and the interest in the project.
  • @FooBarWidget for working and helping with remote debugging.