ruby script for tallying "orphaned" branches in a git-based repo.

branch-blame.rb

#!/usr/bin/env ruby

# in this project, the branching convention is that feature development
# and fixes are worked on in branches prefixed with feature/ and fix/ respectively. 
# These branches are intended to be short-lived, only kept on the remote repo long
# enough for collaboration and eventual Pull Request approval/merging into the 
# develop branch. After merging, the remote branch should be removed, ideally by the 
# repo management software (Stash, github, etc.). If the management software does
# not support automatic deletion of the branch then it is the responsibility of
# the "owner" of the remote branch to delete it--this is generally the creator
# of the branch or the developer who primarily worked on the task. 
#
# This script will display a tally by author of the remote branches in the 
# feature/* and fix/* namespace. It will then print each branch and the oneline
# commit message for the HEAD of each branch, grouped by author.
#
# There are opportunities for "false postives"; specifically, the last author of
# a commit on a branch may not be the "owner"--eg. another developer appends a commit
# to an existing branch during the pull request process, or branches which have not yet
# been merged and correctly remain on the remote repo. Also, some authors may be listed
# by multiple e-mail addresses. This seems to be due to different local and Stash
# configurations in user information. Future enhancement of this script
# could address these issues.
#
# usage:
# * cd into the local repo, anywhere in the repo. 
# * be sure to update the remote branch, pruning already deleted branches:
# ** $ git fetch --prune origin 
# $ ruby branch-blame.rb

# list all branches then filter just the remote feature/* and fix/* branches (assuming "origin" as canonical):
branches = `git branch -a|grep -E "origin/(feature|fix|update)"`

# trim any leading whitespace:
branches = branches.split( /\r?\n/ ).map(&:lstrip)
#puts branches

# get the HEAD commit for each branch:
commits = branches.map {|b| `git log -n1 --pretty="%h %cd (%an) %s" --date=relative #{b}`}
#puts commits

# get author for each HEAD commit:
perps = branches.map {|b| `git log -n1 --pretty="%an" #{b}`}
#puts perps.sort

# create an array to hold the hash-based commits:
perpsWithMessages = []
for i in 0..perps.length-1
  perpsWithMessages.push(Hash[:name, perps[i],
                              :commit, commits[i],
                              :branch, branches[i] ])
end

# print the count of remotes:
puts "Likely orphaned branches: " + branches.length.to_s + "\n\n"

# sort the branches by author name:
if Array.method_defined? :sort_by!
  perpsWithMessages.sort_by! { |hsh| hsh[:name] } # seems only supported on ruby v1.9+ (not Mac OS X default)
else
  perpsWithMessages = perpsWithMessages.sort_by { |hsh| hsh[:name] } # did not seem to sort correctly...non-deterministic.
end

# print the tally of branches by author name:
perpsWithMessages.group_by {|x| x[:name] }.each {|i| 
  puts "(#{i[1].length})\t" + i[0]
}
puts "\n\n"

# print the full list of commits/branches, grouped by author name:
perpsWithMessages.group_by {|x| x[:name] }.each {|i| 
  # first, print the author name:
  puts "(#{i[1].length}) " + i[0]
  
  # then HEAD commits for each branch
  i[1].each {|c| puts c[:branch], c[:commit], "\n" }
  puts "\n"
}

# all done:
exit 0