Re: bug report - BUG: builtin/pack-objects.c:4310: should_include_obj should only be called on existing objects

Elijah Newren [off-list ref] writes:

Cc'ing the author of that commit for his comments.

I took a look. I'm not sure why I made the assumption that
should_include_obj() would only ever be called on objects in the repo
- in process_tree() in list-objects.c, the case of a missing object is
handled only after should_include_obj() is called. Looking back at the
earliest mention of this on the list [1] I don't see any clues either.

In any case, the fix is probably to change it so that
should_include_obj() returns 0 if the object is absent.

Having said that, I couldn't come up with a test that exercises this
failure mode. Nik, do you have a minimal repo that reproduces this
error? If yes, if you could contribute a test in the form of the 'after
fetching descendants of non-promisor commits, gc works' test in t5616,
that would help prevent regressions in the future.

[1] https://lore.kernel.org/git/fb2c202591b466eea33b4585e47b70e9086603bb.1729549127.git.jonathantanmy@google.com/ (local)