On Fri, Jun 02, 2023 at 06:12:52PM -0700, Elijah Newren wrote: > > Also a bunch of the heads are missing. It's pretty clear that right in > > the middle of printing one of the SHAs we suddenly lost a bunch of > > output, and started printing stuff from later (in the last instance 66 > > out of 131 heads were missing). Breaking down the output above you can > > see: > > > > 3a2e8036a6f6605d4dd14c72bd395298bff9d80e refs/heads/xxx2 > > 795d2ff669041fc91341cf5bf820aibab79dc92bd741e77a7dcf71d94285a6ae494dc0 refs/heads/yyy1 > > ^ > > > > where the "795d2ff669041fc91341cf5bf820a" before the "i" char is a > > valid start of a SHA for a head (not shown), then the "i", then a fully > > valid SHA for heads/yyy1 which is 66 heads later. > > Sounds kind of like > https://lore.kernel.org/git/6786526.72e2EbofS7@devpool47/ which also > triggered for some other tooling and then was reduced down to some > shell commands. Unfortunately, the thread ended without a lot of > resolution other than "don't mix stdout and stderr" and "if we slow > down the network connection somehow, that'll avoid the problem". Thanks for digging up that thread. I had a vague memory of this coming up before, but wasn't sure what to search for to find it. :) >From that thread, one theory that I think remains unexplored: could ls-remote's stdout be opened in non-blocking mode? The output of ls-remote is written with printf(). We don't bother checking for errors from stdio, since typically a write error would result in us getting EPIPE and being killed. But if stdout were unexpectedly in non-blocking mode, we might get EAGAIN. I'm not sure how libc would handle that. Now, why the descriptor would be in non-blocking mode, I have no idea. But maybe something funny going on in your python script. I'd be curious if applying the patch from: https://lore.kernel.org/git/YUTo1BTp7BXOw6K9@xxxxxxxxxxxxxxxxxxxxxxx/ reports any problems. As well as whether the suggested "sleep" pipeline there (triggered via your script in this case) shows the problem more reliably. -Peff
