git-insert-module

#!/bin/bash

# script-wide globals
script="$0"
root="$(readlink -f $(dirname "$script"))"
tmpDir="/tmp/.gim"

# globals set by parseArgs
repo1=""
repo2=""

function moveToDirectory() {
	local origin="$1"
	local dest="repo1"

	# create a copy of repo1
	cd $tmpDir
	git clone $origin $dest
	cd $dest

	# make repo1 look like it was always in a directory
	git filter-branch --prune-empty --tree-filter "
	if [[ ! -e $dest ]]; then
		mkdir -p $dest
		git ls-tree --name-only \$GIT_COMMIT \
		   | xargs -I files mv files $dest
	fi"
}

function insertModule() {
	# create another copy
	local origin="$1"
	local moduleOrigin="$2"
	local moduleBranch="master" # Default

	cd $tmpDir
	git clone $origin merged
	cd merged

	git remote add -f repo2 $moduleOrigin
	git merge -s ours --no-commit repo2/$moduleBranch
	git read-tree --prefix=repo2/ -u repo2/$moduleBranch
	git commit -m "Merged repo2"
	git pull -s subtree repo2 $moduleBranch
}

function parseArgs() {
	local argv="$@"
	repo1="$1"
	repo2="$2"
}

function main() {
	parseArgs $@
	mkdir $tmpDir
	cd $tmpDir
	moveToDirectory $repo1 	
	insertModule repo1 $repo2
}

main $@