bugspots3 0.1

Bugspots is a Python implementation of the bug prediction algorithm used at Google.

# bugspots

## What is bugspots?

Bugspots is a Python implementation of
[the bug prediction algorithm used at Google][1].
It also embed a command-line interface which can be used to list the "hot spots"
of a Git repository.

[1]: http://google-engtools.blogspot.com/2011/12/bug-prediction-at-google.html

### What is a hot spot?

A hot spot is merely a file that is bug-prone.

## How does it work?

The algorithm is very simple and to the point: it gives each file a score based
on its number of bug-fixing commits and their age, and then return a
descending-ordered list of the files based on their score, filtering commits
that are no longer at `HEAD`.

### What is a bug-fixing commit?

Any commit whose purpose is to fix an issue. They are identified by message,
using [the same pattern as GitHub][2], which is:

(?i)(fix(e[sd])?|close[sd]?) #[1-9][0-9]*

[2]: https://github.com/blog/831-issues-2-0-the-next-generation

### What is the formula used?

![`\textrm{score}{\left(i\right)}=\sum_{i=0}^n\frac{1}{1+e^{\left(-12t_i+12\right)}}`][3]

where *t_i* is the timestamp of the *i*th commit, normalized between 0 and 1
(0 being the date of the first commit in the repository and 1 being the date of
the last commit in the repository), and *n* is the number of bug-fixing commits.

[3]: http://goo.gl/Uoave

## Installation

$ pip install bugspots

## Command-line usage

$ bugspots.py -h

## Python example

```python
import bugspots
b = bugspots.Bugspots()
for hotspot in b.get_hotspots():
print(" %6.3f %s" % (hotspot.score, hotspot.filename))
```