Script to delete all remote branches that have been merged into master.

delete_branches.py

from subprocess import check_output, check_call
import sys

USAGE = """Error: invalid arguments.
    usage: python delete_branches.py local_repository [remote]
remote defaults to 'origin' if not given."""

try:
    REPO = sys.argv[1]
except IndexError:
    print(USAGE)
    sys.exit(1)
try:
    REMOTE = sys.argv[2]
except IndexError:
    REMOTE = 'origin'
if len(sys.argv) > 3:
    print(USAGE)
    sys.exit(1)


# Ensure we know about all remote branches:
check_call(['git', 'fetch', '--prune', REMOTE], cwd=REPO)

# Get a list of all remote branches that are merged into <REMOTE>/master
output = check_output(
    [
        'git',
        'branch',
        '-r',
        '--merged',
        f'{REMOTE}/master',
        '--format',
        '%(refname:short)',
    ],
    cwd=REPO,
)

branches = output.decode().splitlines()

# Only delete branches from the given remote, and not HEAD or master:
branches_to_delete = []
for branch_path in branches:
    remote, branch = branch_path.split('/', 1)
    if remote == REMOTE and branch not in ('HEAD', 'master'):
        branches_to_delete.append(branch)

# Delete 'em:
for i, branch in enumerate(branches_to_delete):
    print(f"({i+1}/{len(branches_to_delete)}) deleting {REMOTE}/{branch}...")
    check_call(['git', 'push', REMOTE, '--delete', branch], cwd=REPO)