helpers.py

import subprocess


def update_changelog_file(
        changelog_path: str,
        release_notes: str,
        log: 'logging.Logger'
):
    """Prepend the given release notes to CHANGELOG.md."""
    # TODO: exceptions
    try:
        with open(changelog_path, 'r') as changelog:
            original_contents = changelog.read()
        with open(changelog_path, 'w') as changelog:
            changelog.write(release_notes + "\n" + original_contents)
    except OSError as exc:
        log.exception('An unknown error occurred while updating the changelog file.')
        raise exc


def run_subprocess(args: list, cwd: str=None):
    """Run the local command described by `args` with some defaults applied."""
    return subprocess.run(
        args,
        stdout=subprocess.PIPE,
        stderr=subprocess.STDOUT,  # Combine out/err into stdout; stderr will be None
        universal_newlines=True,
        check=True,
        cwd=cwd,
    )


def bump_version(version: str, release_type: str) -> str:
    """Perform a version bump in accordance with semver.org."""
    if release_type == 'Hotfix':  # Don't bump the version number, just append the suffix
        return str(version) + '-Hotfix'
    else:
        MAJOR = 0
        MINOR = 1
        PATCH = 2

        # TODO: exceptions
        release_type = vars()[release_type.upper()]
        version_array = [int(x) for x in version.split('.', 2)]
        version_array[release_type] += 1
        version_array[release_type+1:] = [0] * (PATCH - release_type)

        return '.'.join(str(version) for version in version_array)