Runs rubocop and shows only the offenses you introduced since the fork point


rubocop-changes


I'm a daily user of [Tmux](https://github.com/tmux/tmux) as my favorite
terminal multiplexer. One day, talking to
[Jorge](https://github.com/Morantron), he impressed me with a new hint
picker in the terminal. He was able to pick paths, sha's and other
interesting stuff with few keystrokes. My reaction was priceless.

Jorge did an extraordinary job, building all necessary pieces in Bash to
achieve the text picker behaviour. He only deserves my gratitude for all the
time I have been using
[tmux-fingers](https://github.com/Morantron/tmux-fingers).

During a [Fosdem](https://fosdem.org/) conf, we had the idea to rewrite it to
another language. He had these thoughts many times ago but it was hard to start
from scratch. So, we decided to start playing with Node.js and
[react-blessed](https://github.com/Yomguithereal/react-blessed), but we
detected some unacceptable latency when the program booted. We didn't
investigate much about this latency.

During those days another alternative appeared, called
[tmux-picker](https://github.com/RTBHOUSE/tmux-picker), implemented in python
and reusing many parts from
[tmux-fingers](https://github.com/Morantron/tmux-fingers). It was nice, because
it was fast and added original terminal color support.

I was curious to know if this was possible to be written in
[Rust](https://www.rust-lang.org/), and soon I realized that was something
doable. The ability to implement tests for all critic parts of the application
give you a great confidence about it. On the other hand, Rust has an awesome
community that lets you achieve this kind of project in a short period of time.

## Demo
[![demo](https://asciinema.org/a/232775.png?ts=1)](https://asciinema.org/a/232775?autoplay=1)


A lightning fast version of tmux-fingers written in Rust, copy/pasting tmux like vimium/vimperator


tmux-thumbs


In [Factorial](https://www.factorialhr.com), we had the need to know during the
CI analysis which pull request were introducing new
[Rubocop](https://rubocop.org) offenses in our source code.

The requirement was a bit tricky. We didn't want existing offenses in our
source code, only the new ones. This let us to set an starting point as a
threshold of offenses to start decreasing it to zero.

There are similar projects out there, like
[rubocop-git](https://github.com/m4i/rubocop-git),
[diffcop](https://github.com/yohira0616/diffcop),
[nexocop](https://github.com/SimpleNexus/nexocop), but not all of them offer
differences at line level. Only
[rubocop-git](https://github.com/m4i/rubocop-git) offer this nice feature but
you have to craft the commit id to get the proper fork point of your pull
request.

For this reason, I created `rubocop-changes`. Also, I was a bit curious to play
with git diff and Rubocop output. The idea was to cross both outputs to know
exactly in which line there were new offenses.

This is just an example of a failing pull request with one offense:
```
== components/importer/app/services/workbook.rb ==
C:145: 28: Style/TrailingCommaInArguments: Avoid comma after the last parameter of a method call.

12 files inspected, 1 offense detected
```

If you want to play with it, you have it available as a gem in
[RubyGems](https://rubygems.org/gems/rubocop-changes).


~ferran.basora