Re: [PATCH 2/3] oidmap: add size function

> On Mon, May 12, 2025 at 02:51:30PM -0400, Jeff King wrote:
> > Callers which want to know how many items are in an oidmap have to look
> > at the underlying hashmap struct, leaking an implementation detail.
> > Let's provide a type-appropriate wrapper and use it.
> > 
> > Note in the call from lookup_replace_object(), the caller was actually
> > looking at the hashmap's tablesize parameter (the allocated size of the
> > table) rather than hashmap_get_size(), the number of items in the table.
> > This probably should have been checking the number of items all along,
> > but the two are functionally equivalent here since we only add to the
> > map and never remove anything. Thus if there was any allocation, it was
> > because there is at least one item.
> 
> I was a bit puzzled by this explanation initially. The two sizes aren't
> functioally equivalent -- the table size will typically be larger than
> the number of contained entries. But the thing is that we don't care for
> the actual size, we only care whether the map is empty or not. And for
> that those are indeed equivalent in this specific case.