"""Verify the release's checked file set using the Python standard library."""
import hashlib
from pathlib import Path
import sys

root = Path(sys.argv[1] if len(sys.argv) > 1 else '.').resolve()
seen = set()
for line in (root / 'SHA256SUMS.txt').read_text(encoding='utf-8').splitlines():
    digest, relative = line.split('  ', 1)
    path = (root / relative).resolve()
    if root not in path.parents or relative in seen:
        raise ValueError('Unsafe or duplicate checksum entry: ' + relative)
    seen.add(relative)
    if hashlib.sha256(path.read_bytes()).hexdigest() != digest:
        raise ValueError('Checksum mismatch: ' + relative)
print('PASS: ' + str(len(seen)) + ' files match SHA256SUMS.txt')