Not even once!

Run relevant code-checking tools on your code, before it is even checked in locally. Using the Ruby project Overcommit, you can set this up on your own machine in a jiffy. Or, read more about git hooks.

I took these steps:

1. Install the overcommit gem in your active Ruby. gem i overcommit
2. Install overcommit in your system Ruby, using this neat trick:PATH=/usr/bin:/bin:/usr/sbin:/sbin sudo gem install overcommit – This makes it available to tools like SourceTree! (On committing, it opens a bare shell, without your cool settings.)
3. In your project directory, where you wish to begin using Overcommit to run Git hooks: overcommit --init
4. Configure the resulting .overcommit.yml to enable/disable the checks you want run.
5. Try committing a file which would fail a check.
6. Profit!

PS: Here is an example .overcommit.yml:

PreCommit:
  ALL:
    problem_on_unmodified_line: warn
  CoffeeLint:
    enabled: true
  RuboCop:
    enabled: true