Re: [PUB]corrupt repos does not return error with `git fsck`

Jeff King [off-list ref] writes:

We could add a has_sha1_file() check in get_sha1 for this case.

Please don't.  get_sha1() is merely "I have this string, which may
be a 40-hex or an extended SHA-1 expression.  Turn it into a 20-byte
binary" and does not require you to have any such object.