A better pre-commit hook for git.

Install the gem

$ gem install pre-commit

Use the pre-commit command to generate a stub pre-commit hook

# In your git repo
$ pre-commit install

This creates a .git/hooks/pre-commit script which will check your git config and run checks that are enabled.

If you want to use Bundler to specify a version of RuboCop, add the following to Gemfile:

group :development do
  gem "pre-commit", require: false
  gem "rubocop", require: false
end

And run the following to run pre-commit via Bundler:

$ git config pre-commit.ruby "bundle exec ruby"

If you are using rvm you need to install pre-commit into the default gemset, because it does not use the current environment

$ rvm default do gem install pre-commit

Alternatively you can configure pre-commit to use the current rvm gemset

$ git config pre-commit.ruby "rvm `rvm current` do ruby" # OR:
$ git config pre-commit.ruby `rvm wrapper current show ruby` # available in RVM 1.26.12

These are the available checks:

• white_space
• console_log
• debugger
• pry
• tabs
• jshint
• js_lint
• php (Runs php -l on all staged files)
• rspec_focus (Will check if you are about to check in a :focus in a spec file)
• ruby_symbol_hashrockets (1.9 syntax. BAD :foo => "bar". GOOD foo: "bar")
• local (executes config/pre-commit.rb with list of changed files)
• merge_conflict (Will check if you are about to check in a merge conflict)
• migrations (Will make sure you check in the proper files after creating a Rails migration)
• ci (Will run the pre_commit:ci rake task and pass or fail accordingly)
• rubocop (Check ruby code style using the rubocop gem. Rubocop must be installed)
• before_all (Check your RSpec tests for the use of before(:all))
• coffeelint (Check your coffeescript files using the coffeelint gem.)
• gobuild (Runs go build and fails if can't compile)
• gofmt (Runs go fmt on go source files and fail if formatting is incorrect)
• scss_lint (Check your SCSS files using the scss-lint gem)
• yaml (Check that your YAML is parsable)
• json (Checks if JSON is parsable)

Use pre-commit list to see the list of default and enabled checks and warnings.

git config pre-commit.checks "[whitespace, jshint, debugger]"

To disable, simply leave one off the list

git config pre-commit.checks "[whitespace, jshint]"

pre-commit <enable|disable> <git|yaml> <checks|warnings> check1 [check2...]

The git provider can be used for local machine configuration, the yaml can be used for shared project configuration.

Example move jshint from checks to warnings in yaml provider and save configuration to git:

pre-commit disable yaml checks   jshint
pre-commit enable  yaml warnings jshint
git add config/pre_commit.yml
git commit -m "pre-commit: move jshint from checks to warnings"

Example config/pre_commit.yml:

---
:warnings_remove: []
:warnings_add:
- :jshint
- :tabs

This functionality was added in version 0.17.0

pre-commit run              # run on the files added to index not yet commited
pre-commit run all          # run on all files in current directory
pre-commit run git          # run on all git-tracked files, respect gitignore (added in 0.19.0)
pre-commit run <file-list>  # run on the list of files, patterns not supported

pre-commit comes with 4 configuration providers:

• default - basic settings, read only
• git - reads configuration from git config pre-commit.*, allow local update
• yaml - reads configuration from /etc/pre_commit.yml, $HOME/.pre_commit.yml and config/pre_commit.yml, allows config/pre_commit.yml updates
• env - reads configuration from environment variables

pre-commit uses git to get list of files to check, you can ignore the list of git files to check with:

1. .gitignore - git supported file shared beteen all checkouts
2. .git/info/exclude - git supported file only for this checkout
3. .pre_commit.ignore - pre-commit specific list can be shared, Allowed filters