Re: [RFC PATCH 5/6] object-name: use hexval

On 2026-08-25 at 19:44:34, Elijah Newren wrote:

On Wed, Jul 29, 2026 at 4:33 PM brian m. carlson
[off-list ref] wrote:

quoted

We've open-coded a different implementation of parsing hex values here
when we already have a perfectly good one in hexval.  This
implementation will almost certainly be slower because it isn't
table-driven, unlike the other one, and since it's not constant time it
has no other advantages either.  To tidy things up and prepare for
future work, switch to hexval in this case.

As Junio noted, you may want to call out that your replacement drops
the case-normalization that the former parse_oid_prefix() provided.

Will fix in v2.

[...]

quoted

-               unsigned char val;

[...]

quoted

+               int val = hexval(c, HEX_KIND_OID);
+
+               if (val < 0)
                        return -1;

[...]

quoted

               if (oid_out) {
                       if (!(i & 1))
                               val <<= 4;
                       oid_out->hash[i >> 1] |= val;

hexval returns unsigned int.  Is there a risk that someone "tries to
fix" that discrepancy by changing val to unsigned int here,
inadvertently causing the `if` immediately below to become dead code?

In patch 1, in hex2chr, you used a (val & ~0xf) check together with an
unsigned int val; would that make sense here, or is that overkill?

I can re-roll with an appropriate change, sure.  I think that we'd need
to have a slightly different check, but I'll tidy it up accordingly.
-- 
brian m. carlson (they/them)
Toronto, Ontario, CA