Re: [PATCH 19/23] read_packed_refs(): report unexpected fopen() failures

From: Jeff King <peff@peff.net>
Date: May 17, 2017, 13:28 UTC
Message-ID: <20170517132839.fx6oebgqt5t65tia@sigill.intra.peff.net>
In-Reply-To: <5d13d0f0e0a63430a9bf2889e9a9e911382170de.1495014840.git.mhagger@alum.mit.edu>

On Wed, May 17, 2017 at 02:05:42PM +0200, Michael Haggerty wrote:

Show 6 quoted lines

> The old code ignored any errors encountered when trying to fopen the
> "packed-refs" file, treating all such failures as if the file didn't
> exist. But it could be that there is some other error opening the
> file (e.g., permissions problems), and we don't want to silently
> ignore such problems. So report any failures that are not due to
> ENOENT.

I think there are may be other "OK" errno values here, like ENOTDIR. That's probably pretty unlikely in practice, though, as we're opening a file at the root of the $GIT_DIR here (so somebody would had to have racily changed our paths). It's probably fine to just err on the side of safety.

Show 12 quoted lines

> +	if (!f) {
> +		if (errno == ENOENT) {
> +			/*
> +			 * This is OK; it just means that no
> +			 * "packed-refs" file has been written yet,
> +			 * which is equivalent to it being empty.
> +			 */
> +			return packed_refs;
> +		} else {
> +			die("couldn't read %s: %s",
> +			    packed_refs_file, strerror(errno));
> +		}

I think this could be die_errno().

-Peff