Start a new repository based on the commit hash of another repository

git-spawn-repo-from-commit_hash

#!/bin/bash

#	Copyright (c) 2009 Frogstarr78 Software
#
#	Permission is hereby granted, free of charge, to any person obtaining
#	a copy of this software and associated documentation files (the
#	"Software"), to deal in the Software without restriction, including
#	without limitation the rights to use, copy, modify, merge, publish,
#	distribute, sublicense, and/or sell copies of the Software, and to
#	permit persons to whom the Software is furnished to do so, subject to
#	the following conditions:
#
#	The above copyright notice and this permission notice shall be
#	included in all copies or substantial portions of the Software.
#
#	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
#	EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
#	MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
#	NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
#	LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
#	OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
#	WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.


# This was written with the desire to create a new git repo based on a partial
# history of commits from another repo. e.g.
#
#                            A´--B´--C´ topic
#                           /
#              D---E---F---G master
#                      \
#                       \
#                        New Git Repository
# 
# In the git repository, with this graph, you'd run this file as:
# git-spawn-repo-from-commit_hash /path/to/new/repo F
# 
# the commit_hash argument is optional. You will be prompted for it if you don't provide it.

if [[ $# < 1 ]]
then
	echo "Usage: $0 new_git_repository_path [commit_hash]"
	exit 1
fi

original_git_repo_path=`pwd`
new_git_repo_path=$1
project_name=`basename $new_git_repo_path`

if [[ $# -eq 2 ]]
then
	commit_hash=$2
else
	git log | less 
	# I've set my pager to be cat
	echo "Please provide the commit-hash that you want to start on:"
	read commit_hash
fi

git format-patch --inline=boundary --full-index -M -B -z $commit_hash
if [[ $? -ne 0 ]]
then
	echo "Unable to format-patch based on the provided commit+hash [$commit_hash]."
	exit 1
else
	cd `dirname $new_git_repo_path`

	# I'm living in a ruby world
	# and I'm a ruby girl... or guy... 
	# nm it isn't getting any better! :D
	which jeweler
	if [[ $? -eq 0 ]]
	then
		jeweler $project_name
	else
		which sow
		if [[ $? -eq 0 ]]
		then
			sow $project_name
		else
			mkdir $new_git_repo_path
		fi
	fi

	cd $new_git_repo_path
	mkdir $new_git_repo_path/tmp
	mv $original_git_repo_path/*.patch $new_git_repo_path/tmp/

	if [[ ! -d '.git' ]]
	then
		git init
		git add .
		git commit -m "Initial commit"
	fi

	done_patching_patches='n'
	until [[ $done_patching_patches == 'y' || $done_patching_patches == 'Y' ]]
	do
		echo "Are you done manually fixing the patch files (y|n) ?"
		read done_patching_patches
	done

	cat tmp/*.patch | git am --whitespace=nowarn
	git log 

fi