Hack script to import selected folders from one git repository to another

brad_gff_import.py

#Copyright 2011 Peter Cock, released under GPL v3 licence
#
#Hack script to extract files in selected directories in one git
#repository and apply them to another repository using a potentially
#different directory structure.
#
#This written in Python and needs the git library, I used 0.3.2 RC1
#https://github.com/gitpython-developers/GitPython
#
#I assume when run both repositories are clean (no untracked files,
#uncommitted changes etc) and are in the branches of interest. That
#means in my case a fresh new branch in the destination repo.
#
#This was written to extract from GFF code for Biopython from
#https://github.com/chapmanb/bcbb/tree/ (master branch)
#to a branch of the main Biopython repository,
#https://github.com/chapmanb/bcbb/tree/
#
#TODO - Commits deleting files probably don't work (untested)

import os
import subprocess
import time
from git import Repo

source = "/Users/peterjc/repositories/bcbb"
dest = "/Users/peterjc/repositories/biopython"

source_repo = Repo(source)
dest_repo = Repo(dest)

directory_map = {
    "gff/BCBio/GFF": "Bio/GFF",
    "gff/Tests": "Tests/",
}

assert not source_repo.bare
assert not source_repo.is_dirty()
assert not dest_repo.is_dirty()


def apply_patch(original_commit):
    hash = str(original_commit)
    author = '"%s <%s>"' % (original_commit.author.name, original_commit.author.email)
    print hash, author
    print str(original_commit.message).strip().split("\n",1)[0].strip()
    original_patch = source_repo.git.show(source_commit, "--", *directory_map.keys())
    patch = original_patch.rstrip("\n") + "\n"
    for pre in [" a/", " b/"]:
        for old, new in directory_map.iteritems():
            patch = patch.replace(pre+old, pre+new)
    os.chdir(dest)
    h = open("%s.patch" % hash, "w")
    h.write(patch)
    h.close()
    h = open("%s.txt" % hash, "w")
    for line in original_commit.message.strip().split("\n"):
        h.write(line.strip() + "\n")
    h.close()
    #print patch
    print "Patch and message prepared"
    return_code = os.system("patch -p 1 -i %s.patch" % hash)
    assert not return_code, return_code
    print os.getcwd()
    print "Patch applied"
    files = []
    for line in patch.split("\n"):
        if line.startswith("+++ b/"):
            files.append(line[6:].strip())
    for f in files:
        print f
        assert os.path.isfile(f), f
        dest_repo.git.add(f)
    dest_repo.git.commit("--author", author,
                         "-F", "%s.txt" % hash,
                         "--date", original_commit.authored_date)
    print "Done"


selected_commits = list(source_repo.head.commit.iter_parents(paths=directory_map.keys()))[::-1]

for source_commit in selected_commits:
    print source_commit, time.asctime(time.gmtime(source_commit.committed_date))

print "Working..."
for source_commit in selected_commits:
    apply_patch(source_commit)