Re: [ANNOUNCE] Git v2.34.0-rc2

Jeff King [off-list ref] writes:

On Thu, Nov 11, 2021 at 09:32:29AM -0800, Junio C Hamano wrote:

quoted

...  So in this particular example, it would not matter if the
new unsorted traversal is subtly broken (I think the extent of the
damage is similar to making the SLOP problem deliberately worse),
but I am not sure if there are other failure modes that would yield
outright incorrect result.

Yes, I think that framing is right: it is making SLOP much worse. We
could similarly have had bogus timestamps in those commits which would
cause the same outcome. So in that sense it is nothing new. On the other
hand, I wonder how often it will cause extra traversal work (keeping in
mind that this commit traversal is just the first stage; after we find
the commits, then we talk all of their trees, which is the more
expensive part).

For the case of adding new commits directly on top of another branch, I
think there would be no change. But any time you have to walk down to a
common fork point (e.g., imagine I made a new branch forked from an old
bit of history), we may fail to find that. I haven't quite constructed
an example, but I have a feeling we could end up walking over
arbitrarily long segments of history.
...
I'd be curious to hear Patrick's thoughts on the whole thing.

Yes.  I'm tempted to wait for him to chime in.