On 2019.04.13 01:34, Jeff King wrote: > On Fri, Apr 12, 2019 at 03:38:47PM -0700, Josh Steadmon wrote: > > > > > Thank you for catching this. I haven't yet figured out the cause. I will > > > > look into this more tomorrow and then send a V4 once I've fixed it. > > > > > > I'm concerned that this is a sign that the approach I suggested does not > > > actually work everywhere. I.e., could this be a case where we have some > > > non-promisor object that points to a sub-object that is reachable from > > > the promisor pack, but not a direct tip? Before your patch we'd consider > > > that sub-object a promisor (because we enumerate all of the graph that > > > we do have and mark each such object), but afterwards we would not. > > > > > > And I wonder if that confuses pack-objects. Though I think it would > > > confuse it in the _opposite_ direction. I.e., using > > > --exclude-promisor-objects would count such an object as not-a-promisor > > > and would be more inclined to include it in the new pack. > > > > > > It is curious that this only turns up with GIT_TEST_COMMIT_GRAPH=1, too. > > > It seems like any such problem ought to be independent of that. > > > > > > Puzzling... > > > > Do you think this justifies going back to the V1 approach (only checking > > presence of objects pointed to by refs when doing a partial clone)? > > Yes, I think it might. Especially coupled with your other report that > the V1 approach is 500ms compared to several seconds for this one. Which > I'd guess is probably because we actually parse the ref tip objects in > rev-list, whereas your V1 just skipped that step entirely (which is > perfectly fine for a clone, as we'd have just hashed the objects via > index-pack anyway). > > It might be interesting to know if the problem is indeed insurmountable > with the V3 approach here, or if it's simply another bug. But diving > into it is going to be rather tricky, and I am not volunteering to do > it. :) So if you want to punt and go back to the more clearly correct V1 > approach, I can live with that. We can always revisit this approach > later (it wouldn't be necessary for the clone case after your V1, but in > theory it could be helping other cases, too). > > -Peff I have not made any progress in figuring out the repack + commit-graph failure, so I will resend V1.
