In the very infrequent case that we re-upload a file, the logic for
upload-release would have the existing SHA256SUM take precedence over
the new one -- despite uploading the new file.
Skip existing filenames (i.e. from the new file) when gathering
SHA256SUM metadata used to assemble `SHA256SUMS.txt`.
Appending to bytes in a loop leads to a quadratic slowdown since
Python doesn’t optimize this for bytes like it does for str.
Signed-off-by: Anders Kaseorg <anders@zulip.com>
Anders Kaseorg
Alex Vandiver