On Fri, Feb 17, 2023 at 2:41 PM brian m. carlson
[off-list ref] wrote:

On 2023-02-17 at 21:38:34, Emily Shaffer wrote:

quoted

For example, I seem to remember you saying during the SHA-256 series
that the next hashing algorithm would also be painful to implement;
would that still be true if the hashing algorithm is encapsulated well
by a library interface? Or is it for a different reason?

Right now, most of the code for a future hash algorithm wouldn't be too
difficult to implement, I'd think, because we can already support two of
them.  If we decide, say, to implement SHA-3-512, we basically just add
that algorithm, update all the entries in the tests (which is kind of a
pain since there's a lot of them, but not really difficult), and then
move on with our lives.

The difficulty is dealing with interop work, which is basically
switching from dealing with just one algorithm to rewriting things
between the two on the fly.  I think _that_ work would be made easier by
library work because sometimes it involves working with submodules, such
as when updating the submodule commit, and being able to deal with both
object stores more easily at the same time would be very helpful in that
regard.

Ooh, I see what you mean. Thanks for the extra context here.

I can imagine there are other things that would be easier as well, and I
can also imagine that we'll have better control over memory allocations
and leak less, which would be nice.  If we can get leaks low enough, we
could even add CI jobs to catch them and fail, which I think would be
super valuable, especially since I find even after over two decades of C
that I'm still not very good about catching all the leaks (which is one
of the reasons I've mostly switched to Rust).  We might also be able to
make nicer steps on multithreading our code as well.

Personally, I'd like to see some sort of standard error type (whether
integral or not) that would let us do more bubbling up of errors and
less die().  I don't know if that's in the cards, but I thought I'd
suggest it in case other folks are interested.

Yes!!! We have talked about this a lot internally - but this is one
thing that will be difficult to introduce into Git without making
parts of the codebase a little uglier. Since obviously C doesn't have
an intrinsic to do this, we'll have to roll our own, which means that
manipulating it consistently at function exits might end up pretty
ugly. So hearing that there's interest outside of my team to come up
with such a type makes me optimistic that we can figure out a
neat-enough solution.

--
brian m. carlson (he/him or they/them)
Toronto, Ontario, CA