git-export-patches

#!/usr/bin/python3
#
# Script to export patches in git
# Exports commits in upstream source git back to patches used in source git.
#
# Usage:
# First generate repository using gitprep
# cd ${SOURCEDIR}
# git remote add upstream <giturl>
# git fetch upstream
# git rebase vX.Y
# git-export-patches

import argparse
import git
import re
import subprocess
import os.path

tag = None
output_dir = '..'
commits_in_row = 3

def commit_parameters(commit):
        keyword = re.compile('\w+')
        params = {}
        for line in commit.message.split('\n'):
            param = line.split(':', 2)
            if len(param)>1 and keyword.match(param[0]):
                params[param[0]] = param[1].strip()
        return params

def process_commit(commit):
    """
    Process one commit
    :returns: True if processed, False if skipped

    Export patch if patch name is provided.
    """
    params = commit_parameters(commit)
    if 'Patch' in params:
        patch = params['Patch']
        gitresult = subprocess.run(['git', 'format-patch', '--stdout', '-1', commit.hexsha], capture_output=True, check=True)
        outputpath = os.path.join(output_dir, patch)
        with open(outputpath, 'wb') as f:
            f.write(gitresult.stdout)
        print('Exported {commit} to {path}.'.format(commit=commit, path=outputpath))
        return True
    return False
        
def process_repo(repo):
    commit_range = None
    if tag:
        commit_range = tag + '..HEAD'
    ignored = 0
    for c in repo.iter_commits(commit_range):
        if process_commit(c):
            ignored=0
        else:
            ignored += 1
            # When 3 commits in row
            if ignored >= commits_in_row:
                print('Terminating processing on commit {commit}'.format(commit=c))
                break

if __name__ == '__main__':
        parser = argparse.ArgumentParser()
        parser.add_argument('-t', '--tag',
            help='starting upstream tag. Export patches just from HEAD to tag')
        parser.add_argument('-o', '--output',
            help='sutput directory for exported patches')
        parser.add_argument('-n', '--ignore-number',
            help='finish, when this number of commits in row do not contain Patch: parameter')
        args = parser.parse_args()
        if args.output:
            output_dir = args.output
        if args.ignore_number:
            commits_in_row = int(args.ignore_number)
        tag = args.tag

        repo = git.Repo()
        process_repo(repo)