A micro Python script for listing the authors in a git repository sorted by the time of their first contribution. Traits:

• Properly deals with the byte stream emitted by git log.
• Supports Python 2.7 and 3.4.
• Supports Linux and Windows.

This has been created mainly for educational purposes. Please read the corresponding article on my blog.

Usage

$ git log --encoding=utf-8 --full-history --reverse "--format=format:%at;%an;%ae" | \
    git-authors > authors-by-first-contrib.txt

git-authors writes a formatted list of authors to stdout. The data is UTF-8-encoded. Lines are separated by a single \n character.

Resource consumption

This script implements on-the-fly stream processing and uses an efficient data structure for keeping track of authors. It therefore requires almost no memory and just a little amount of CPU power. The resource requirements for analyzing a repository are therefore predominantly dictated by whatever git log consumes.

git log performs reasonably fast even for large repositories: with git version 2.1.4, analysis of the Linux repository (with more than 500.000 commits) takes about 7 seconds on a rather slow test machine.

Notes

• Clearly, the output of this script might need higher intelligence for meaningful interpretation, such as for detecting when the same author has used different names.

• The contribution date is extracted from the git data field %at, also known as the "author date". See http://stackoverflow.com/a/11857467/145400.

• It is not uncommon for an author to use different email addresses over time. Hence, authors are distinguished by their name only (specifically, by the git data field %an).

• The output of git log may contain byte sequences that are invalid in the UTF-8 codec. These get replaced with a question mark in the output. For details about how git handles text encoding internally, see http://git-scm.com/docs/git-log#_discussion.

• The note above is valid, independent of the --encoding=utf-8 option.

• It seems that the --encoding option of git log has been removed in quite recent git releases. Remove it from the command line if you observe a corresponding error.

• If this script breaks because it came across an author with a semicolon in his/her name, then blame Little Bobby Tables' mom (https://xkcd.com/327).