Churn

A Project to give the churn file, class, and method for a project for a given checkin. Over time the tool adds up the history of churns to give the number of times a file, class, or method is changing during the life of a project. Churn for files is immediate, but classes and methods requires building up a history using churn between revisions. The history is stored in ./tmp

Currently has full Git, Mercurial (hg), Bazaar (bzr) support, and partial SVN support (supports only file level churn currently)

File changes can be calculated on any single commit to look at method changes you need to be running churn over time. Using a git post-commit hook, configuring your CI to run churn, or using churn-site is the best way to build up your churn history. See the --past_history (-p) option to do a one time run building up past class and method level churn.

Authors:

danmayer
ajwalters
cldwalker
absurdhero
bf4

CI Build Status

This project runs travis-ci.org

TODO

Want to help out, there are easy tasks ready for some attention. The list of items has been moved to the churn wafflie.io

Churn Usage

Install with gem install churn or for bundler add to your Gemfile gem 'churn', :require => false.

The reason you want require false is that when required by default churn is expecting to add some rake tasks, you don't really want or need it loading when running your server or tests.

rake:
- add require 'churn' to Rakefile
- then runrake churn or bundle exec rake churn
- use environment variables to control churn defaults
```
    ENV['CHURN_MINIMUM_CHURN_COUNT']
    ENV['CHURN_START_DATE']
    ENV['CHURN_IGNORE_FILES']
```

CLI:

on command line run churn or bundle exec churn
need help run churn -h to get additional information
run the executable passing in options to override defaults

    churn -i "churn.gemspec, Gemfile" #ignore files
    churn -y #output yaml format opposed to text
    churn -c 10 #set minimum churn count on a file to 10
    churn -c 5 -y -i "Gemfile" #mix and match
    churn --start_date "6 months ago" #Start looking at file changes from 6 months ago
    churn -p "4 months ago" #churn the past history to build up data for the last 4 months
    churn --past_history #churn the past history for default 3 months to build up data

Example Output

**********************************************************************
* Revision Changes
**********************************************************************
Files:
+-------------------------------+
| file                          |
+-------------------------------+
| Rakefile                      |
| lib/churn/churn_calculator.rb |
+-------------------------------+

Classes:
+-------------------------------+-----------------+
| file                          | klass           |
+-------------------------------+-----------------+
| lib/churn/churn_calculator.rb | ChurnCalculator |
+-------------------------------+-----------------+

Methods:
+-------------------------------+-----------------  +-------------------------------+
| file                          | klass           | method                        |
+-------------------------------+-----------------+-------------------------------+
| lib/churn/churn_calculator.rb | ChurnCalculator | ChurnCalculator#filters       |
| lib/churn/churn_calculator.rb | ChurnCalculator | ChurnCalculator#display_array |
| lib/churn/churn_calculator.rb | ChurnCalculator | ChurnCalculator#to_s          |
+-------------------------------+-----------------+-------------------------------+

**********************************************************************
* Project Churn
**********************************************************************
Files:
+------------------------------------+---------------+
| file_path                          | times_changed |
+------------------------------------+---------------+
| lib/churn/churn_calculator.rb      | 14            |
| README.rdoc                        | 7             |
| lib/tasks/churn_tasks.rb           | 6             |
| Rakefile                           | 6             |
| lib/churn/git_analyzer.rb          | 4             |
| VERSION                            | 4             |
| test/test_helper.rb                | 4             |
| test/unit/churn_calculator_test.rb | 3             |
| test/churn_test.rb                 | 3             |
+------------------------------------+---------------+

Classes:
+-------------------------------+-----------------+---------------+
| file                          | klass           | times_changed |
+-------------------------------+-----------------+---------------+
| lib/churn/churn_calculator.rb | ChurnCalculator | 1             |
| lib/churn/churn_calculator.rb | ChurnCalculator | 1             |
+-------------------------------+-----------------+---------------+

Methods:
+-------------------------------+-----------------+-----------------------------------------+---------------+
| file                          | klass           | method                                  | times_changed |
+-------------------------------+-----------------+-----------------------------------------+---------------+
| lib/churn/churn_calculator.rb | ChurnCalculator | ChurnCalculator#to_s                    | 1             |
| lib/churn/churn_calculator.rb | ChurnCalculator | ChurnCalculator#display_array           | 1             |
| lib/churn/churn_calculator.rb | ChurnCalculator | ChurnCalculator#calculate_revision_data | 1             |
| lib/churn/churn_calculator.rb | ChurnCalculator | ChurnCalculator#filters                 | 1             |
| lib/churn/churn_calculator.rb | ChurnCalculator | ChurnCalculator#initialize              | 1             |
| lib/churn/churn_calculator.rb | ChurnCalculator | ChurnCalculator#filters                 | 1             |
| lib/churn/churn_calculator.rb | ChurnCalculator | ChurnCalculator#to_s                    | 1             |
+-------------------------------+-----------------+-----------------------------------------+---------------+

CLI Options

[~/projects/churn] churn -h
NAME
  churn

SYNOPSIS
  churn [options]+

PARAMETERS
  --minimum_churn_count=minimum_churn_count, -c (0 ~>
  int(minimum_churn_count=3))
  --yaml, -y
  --ignore_files=[ignore_files], -i (0 ~> string(ignore_files=))
  --start_date=[start_date], -s (0 ~> string(start_date=))
  --data_directory=[data_directory], -d (0 ~> string(data_directory=))
  --past_history=[past_history], -p (0 ~> string(past_history=))
  --help, -h

Library Options

All the CLI options are parsed and just passed into the library. If you want to run the library directly from other code. The best way to see current options is where the churn executable passes the parsed options into the ChurnCalculator class

###
# Available options
###
options = {:minimum_churn_count => params['minimum_churn_count'].value,
  :ignore_files => params['ignore_files'].value,
  :start_date => params['start_date'].value,
  :data_directory => params['data_directory'].value,
  :history => params['past_history'].value,
  :report => params['report'].value,
  :name => params['name'].value
}
result = Churn::ChurnCalculator.new(options).report(false)

Notes on Patches/Pull Requests

Fork the project.
Make your feature addition or bug fix.
Add tests for it. This is important so I don't break it in a future version unintentionally.
Commit, do not mess with rakefile, version, or history. (if you want to have your own version, that is fine but bump version in a commit by itself I can ignore when I pull)
Send me a pull request. Bonus points for topic branches.