aausch/git-lint

improving source code one step at a time

Git-Lint

Git-lint is a tool for improving source code one step at a time.

Motivation

Often times enforcing coding styles to an existing project can be a nightmare. Some reasons may include:

• the codebase is already a mess and the output of the tools is overwhelming.
• developers don't feel confident changing lines they do not own.
• or they just don't know what tool to use.

Features

This tool tackles all the 3 problems mentioned above by providing just a single tool that lints all the modified files. For each filetype it may use even more than one linter or tool. Furthermore by default it only report problems of lines that were added or modified.

Current linters:

• CSS
  • Csslint
• SCSS
  • scss-lint
• Python
  • Pylint
  • PEP8
• PHP
  • Php Code Sniffer
• Javascript
  • Jshint
  • Gjslint
• JPEG
  • Custom via Jpegtran
• PNG
  • Custom via Pngcrush
  • Custom via Optipng
• RST
  • Via rst2html.py (docutils)
• JSON
  • Via python json.tool module
• YAML
  • yamllint
• INI
  • Custom via ConfigParser module
• HTML
  • HTML-Linter
  • Tidy with preprocessing from template-remover
• Ruby
  • ruby-lint
  • rubocop
• Java
  • PMD (it requires to put the script run.sh in your PATH)
  • Checkstyle
• Coffeescript
  • coffeelint

Example use

Below is the simplest call, for a detailed list, see the help:

$ git lint
Linting file: src/html/main.js
Line 13, E:0110: Line too long (328 characters).
Line 31, E:0001: Extra space at end of line
src/html/main.js: line 75, col 11, ['location'] is better written in dot notation.

Linting file: src/html/main.css
src/html/main.css: line 1, col 135, Warning - Duplicate property 'margin' found.

Linting file: api.py
api.py:6: [C0301(line-too-long), ] Line too long (87/80)
api.py:6: [R0913(too-many-arguments), callMethod] Too many arguments (6/5)
api.py:6: [C0103(invalid-name), callMethod] Invalid function name "callMethod"

By default git lint only reports problems with the modified lines (with the exception of some linters that check that the whole file is sound). To force displaying all the output from the linters use the -f option.

Installation

You can install, upgrade or uninstall git-lint with these commands:

$ pip install git-lint
$ pip install --upgrade git-lint
$ pip uninstall git-lint

Configuration

Git-lint comes with a default configuration that includes all the linters listed above. If you don't like that list you can write your own configuration and put it in a file called .gitlint.yaml in the root of your repository. You can copy the file https://github.com/sk-/git-lint/blob/master/gitlint/configs/config.yaml to your repo and modify it.

If you add a new linter or add a new flag to any of the commands, please share that with us, so we can integrate those changes.

The configuration support two variables for the command, requirements and arguments:

• {REPO_HOME}: the root of your repo.
• {DEFAULT_CONFIGS}: the location of the default config files.

If you need to include strings like {} or {foo} in your command, you need to double the braces as in {{}} or {{foo}}.

Git Configuration

git-lint comes with a pre-commit hook for git. To install it for your repo execute:

$ ln -s `which pre-commit.git-lint.sh` $PATH_TO_YOUR_REPO/.git/hooks/pre-commit

or if you want to install it globally execute instead:

$ ln -s `which pre-commit.git-lint.sh` /usr/share/git-core/templates/hooks/pre-commit

Mercurial Configuration

To make available git-lint with a better name in mercurial you have to add the following to your .hgrc configuration:

[alias]
lint = !git-lint $@

To add a pre-commit hook add the following:

[hooks]
pretxncommit.hglint = pre-commit.hg-lint.sh > `tty`

The hook above has a hack to display the output of the command. Additionally, as mercurial does not provide (AFAIK) any way to skip a hook, if you want to force a commit with linter warnings execute the commit command as follow:

$ NO_VERIFY=1 hg commit ...

Note though that mercurial heavily uses commit to leverage all of their commands/extensions. I've found that setting any sort of precommit hook will get on your way when using common actions as rebase or shelve.

Limitations

In some cases a change will trigger a warning in another line. Those cases are unfortunately not handled by git-lint, as it only reports those lines taht were modified. Fully supporting this use case would require to run the linters twice and report only the new lines. The most common case in which this occurs is with unused imports or variables. Let's say we have the following piece of code:

import foo
foo.bar()

If you remove the second line, git-lint will not complain as the warning is for line 1, which was not modified.

Python Versions

Python 2.7 is supported, and it should also work for Python 3.2, 3.3 and 3.4. Python 2.6 is not supported because of the lack of subprocess.check_output.

Development

Help for this project is more than welcomed, so feel free to create an issue or to send a pull request via http://github.com/sk-/git-lint.

Tests are run using nose, either with:

$ python setup.py nosetests
$ nosetests

This same tool is run for every commit, so errors and style problems are caught early.

Adding a linter

Just need to configure the file gitlint/config.yaml. I hope the syntax is self explanatory. (Note to myself: don't be so lazy and write a proper doc for this.)

TODOS and Possible Features

• Support directories as arguments
• Provide a man page so 'git help lint' and 'git lint --help' work. I already have a script for converting the Usage to a man page, but I still need to figure out how to install it on the system.
• Allow to run a command or function when setting up the linter? These can be achieved now by running a bash script wrapping the linter. The rationale for this is that some linters, like jshint, only allow options to be in a configuration file. This is done at the moment via scripts present in the folder linters.
• Decide what linter to use based on the whole filename or even in the filetype, as returned by the command file.
• Provide better options for colorizing the output, and maybe a way to disable it. Also detect if colors are supported or if it is a tty.
• Add support for more version control systems (svn, perforce). This should be easy, it's just a matter of implementing the functions defined in gitlint/git.py or gitlint/hg.py.
• Support windows.

Contributors

• Rovanion Luckey
• Radek Simko
• Adrien Vergé

Changelog

v0.0.8 (2015-10-14)

• Fixed git pre commit hook (thanks to Rovanion Luckey)
• Fixed issues #64, #67

v0.0.7 (2015-06-28)

• Better support in python 3
• Removed support for Python 3.2
• Output is sorted by line and column number
• Bugfixes: issues #49, #50, #54, #62
• Added coffelint support
• Improved defaults

v0.0.6 (2014-09-08)

• Added mercurial support
• Run e2e tests on Travis

v0.0.5 (2014-05-09)

• Added linters: ruby-lint, rubocop, checkstyle, pmd
• Variables %(REPO_HOME)s and %(DEFAULT_CONFIGS)s can be specified in configuration
• Added default pylintrc configuration

v0.0.4 (2014-05-08)

• Added linters: html, tidy, scss
• Added way to override default configuration
• Improvements for Python3

v0.0.3 (2014-02-02)

• Fixes to the filter syntax
• Fixes to the git parser
• Added linters (YAML, Ini, PHP) and improved linter for PNG and JPEG.
• Improved pylint configuration.
• Improved phpcs configuration.
• Check if program is available and if not display info to install it.
• Cache the output of linters, so subsequent calls are much faster.

v0.0.2 (2013-10-20)

• Fixes to the installer

v0.0.1 (2013-10-20)

• Initial commit with the basic functionalities. Released mainly to collect feedback about the features and the planned ideas.