Run a git command, and then rebase any branches which were built on top of the current one

git-rar.rb

#!/usr/bin/ruby
#GistID: 3779324

require 'escape'

exit if ARGV.empty?

current_branch = `git symbolic-ref -q HEAD`.sub(/^refs\/heads\//, "").strip
exit if current_branch.empty?

def branch_output_to_array(output)
	output.gsub(/^[ *]*/, "").split("\n").collect{ |e| e.strip }
end

IGNORED_BRANCHES = branch_output_to_array(`git branch --no-color -r`) << "HEAD"

def branches_on(commit)
	ignored = IGNORED_BRANCHES << commit

	log = `git log --pretty=%d --simplify-by-decoration #{commit} | head -n 1`
	branches = log.sub(/^ \(([^)]+)\).*$/, '\1').split(", ")
	branches.collect{ |e| e.strip }.reject{ |b| ignored.include? b }
end

def children_of(branch)
	c = branch_output_to_array(`git branch --no-color --contains #{branch}`)
	c.reject!{ |b| b == branch }

	grandchildren = c.collect{|c| children_of c}.flatten
	c.reject{ |b| grandchildren.include? b }
end

def branch_tree_from(branch)
	siblings = branches_on branch
	children = children_of(branch).reject{|c| siblings.include? c}

	tail = siblings.collect{|s| [s]} + children.collect{|c| branch_tree_from(c)}
	tail.empty? ? [branch] : [branch, tail]
end

def rebase_all_children(tree)
	parent = tree.shift
	children = tree.shift
	children.map do |e|
		system "git rebase #{parent} #{e.first}"

		if e.size > 1
			rebase_all_children e
		end
	end
end

initial_tree = branch_tree_from current_branch

if system "git #{Escape.shell_command(ARGV)}"
	rebase_all_children initial_tree
	system "git checkout #{current_branch}"
end