schema/verify_bytes.py

#!/usr/bin/env python3
"""Verify the encoded image bytes stored in the QT26-QC Parquet shards."""

from __future__ import annotations

import argparse
import hashlib
from pathlib import Path

from datasets import Image, load_dataset


def main() -> int:
    parser = argparse.ArgumentParser()
    parser.add_argument(
        "--data",
        default=str(Path(__file__).resolve().parents[1] / "data" / "test-*.parquet"),
        help="Parquet glob or one Parquet file",
    )
    args = parser.parse_args()

    dataset = load_dataset("parquet", data_files=args.data, split="train")
    raw = dataset.cast_column("image", Image(decode=False))
    checked = 0
    for row in raw:
        payload = row["image"]["bytes"]
        if payload is None:
            raise ValueError(f"missing embedded bytes: {row['public_id']}")
        actual = hashlib.sha256(payload).hexdigest()
        if actual != row["image_sha256"]:
            raise ValueError(
                f"SHA-256 mismatch for {row['public_id']}: {actual} != {row['image_sha256']}"
            )
        if len(payload) != row["image_bytes"]:
            raise ValueError(f"byte-length mismatch for {row['public_id']}")
        checked += 1
    print(f"PASS: verified encoded bytes for {checked:,} QT26-QC rows")
    return 0


if __name__ == "__main__":
    raise SystemExit(main())