Subject: Re: [PATCH] revision: ignore non-existent objects in resolve-undo list

From: Junio C Hamano <[email-masked]>
Date: Tue, 18 Oct 2022 09:40:01 -0700

Junio C Hamano <[email-masked]> writes:

>> Fix the error by emitting a warning when the resolve-undo list mentions
>> objects that do not exist and then ignoring the nonexistent object.
>
> ... this approach is about.  I think it is backwards to sweep the
> problem under the rug without fixing the underlying problem.
>
> We should instead be removing the reference that is no longer even
> usable for the purpose of resolve-undo, e.g. when "rerere forget
> <pathspec>" reads from the resolve-undo extension to recreate the
> conflicts.

Ah, I take half of it back.  "instead" -> "in addition".

The patch corresponds to revision.c::handle_one_reflog_commit() that
skips the object referenced by a reflog entry that no longer exists
as part of the solution to the same problem as "reflog --stale-fix"
solved, and needs to be an integral half of the solution to the
"older gc lose blobs referenced by resolve-undo extension" problem.

And the patch goes in the right direction.  It is a bit sad that it
now has to do parse_object() but in the normal case, the object
referenced should be a blob that exists, for which the cost of
parsing it would be none (just setting .parsed member to true), so
it should be OK.

Thanks.  Will queue.