`put_file` partial uploads for files close to 1GB

[rick-warren]

When files are very close to 1 GB (1,048,576 KB), only the first 1 GB of the file is uploaded when using S3FileSystem (I haven't tested with other file systems), whereas using boto3 directly works.

Reverting from version 2024.10.0 to 2024.6.1 fixes the issue (I haven't tested intermediate versions).

Here's a minimal example:

REMOTE_BUCKET = "test_bucket"

def check_fsspec_put(size=1096511984, dtype=np.float64):
    """Compare local and remote file sizes when objects are saved remotely via fsspec."""

    fs = s3fs.S3FileSystem()
    s3 = boto3.client('s3')

    # Create fake data with the given size
    data = np.zeros((size // dtype().itemsize,), dtype=dtype)

    # Save locally and to s3
    np.save(f"fake_data_{size}.npy", data)
    fs.put_file(f"fake_data_{size}.npy", f"s3://{REMOTE_BUCKET}/fake_data_{size}.npy")

    # Return local and remote file sizes
    original_size = os.path.getsize(f"fake_data_{size}.npy")
    fsspec_size = s3.head_object(Bucket=REMOTE_BUCKET, Key=f"fake_data_{size}.npy")["ContentLength"]

    return original_size, fsspec_size

for size in [
    1038576000,  # works
    1096511984,  # fails
    1106511984,  # works
]:
    original_size, fsspec_size = check_fsspec_put(size)
    if original_size != fsspec_size:
        print(f"fsspec only uploaded {original_size} / {fsspec_size} bytes")

[martindurant]

Please test in the main branch, I believe this is fixed

[martindurant]

https://github.com/fsspec/s3fs/pull/910