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Re: [PATCH 2/3] path-walk: fix setup of pending objects

From
Patrick Steinhardt <ps@pks.im>
Date
Aug 21, 2025, 08:01 UTC
Message-ID
<aKbSTN-rfGzadPsm@pks.im>
In-Reply-To
<c6ab0985-2a74-406b-9685-cc65f8748515@gmail.com>
On Wed, Aug 20, 2025 at 03:42:11PM -0400, Derrick Stolee wrote:
Show 26 quoted lines
> On 8/20/2025 3:02 PM, Junio C Hamano wrote:
> > "Derrick Stolee via GitGitGadget" <gitgitgadget@gmail.com> writes:
> > 
> >> The core problem here is that the "maybe_interesting" member of 'struct
> >> type_and_oid_list' is not initialized to '1'. This member was added in
> >> 6333e7ae0b (path-walk: mark trees and blobs as UNINTERESTING,
> >> 2024-12-20) in a way to help when creating packfiles for a small commit
> >> range using the sparse path algorithm (enabled by pack.useSparse=true).
> > 
> > OK, in other words, the bug is fairly contained within the path-walk
> > traversal.  We treat things as reachable not just from ref tips and
> > reflogs (where path-walk code can use the tree object to compute on
> > what pathname each blob comes from) and the main index array (that
> > has paths, even though it needs separate way to compute than those
> > for trees), but also from places like REUC and TREE extensions that
> > make associations between pathnames and objects.  Are they also OK?
> 
> The key integration point is the "pending" list operating a bit
> different from walking directly from tags or commits. I was trying
> to reproduce the issue from all of those other sources before unlocking
> the "singleton" nature of the problem, and failed to do so.
> 
> The resolve-undo cache (REUC) is something that I had not tested
> previously. Adding "git rm --cached x/y" to the test in the previous
> case leads to the 'git fsck' call giving a "dangling blob" warning,
> so that could be an interesting way to strengthen the test. Thanks,

I also wonder a bit about the future -- if we ever add a new source for pending objects, would the author have to amend "path-walk.c" to take this new pending source into account?

I guess the answer is "yes", which does make me feel a bit uneasy as it is very easy to now corrupt the repository.

Patrick
Previous: Derrick StoleeNext: Derrick Stolee
Message 10 of 22 in “[2.51.0 Bug] Missing singleton objects in 'git repack -adf --path-walk'”
  1. 0/3 [2.51.0 Bug] Missing singleton objects in 'git repack -adf --path-walk'Derrick Stolee via GitGitGadget, Aug 20, 2025
  2. 1/3 t7700: add failing --path-walk testDerrick Stolee via GitGitGadget, Aug 20, 2025
  3. Patrick SteinhardtAug 21, 2025
  4. Derrick StoleeAug 21, 2025
  5. Junio C HamanoAug 21, 2025
  6. Elijah NewrenAug 21, 2025
  7. 2/3 path-walk: fix setup of pending objectsDerrick Stolee via GitGitGadget, Aug 20, 2025
  8. Junio C HamanoAug 20, 2025
  9. Derrick StoleeAug 20, 2025
  10. Patrick SteinhardtAug 21, 2025
  11. Derrick StoleeAug 21, 2025
  12. Patrick SteinhardtAug 21, 2025
  13. Derrick StoleeAug 21, 2025
  14. Elijah NewrenAug 21, 2025
  15. 3/3 path-walk: create initializer for path listsDerrick Stolee via GitGitGadget, Aug 20, 2025
  16. Elijah NewrenAug 21, 2025
  17. 0/2 [2.51.0 Bug] Missing singleton objects in 'git repack -adf --path-walk'Derrick Stolee via GitGitGadget, Aug 25, 2025
  18. 1/2 path-walk: fix setup of pending objectsDerrick Stolee via GitGitGadget, Aug 25, 2025
  19. 2/2 path-walk: create initializer for path listsDerrick Stolee via GitGitGadget, Aug 25, 2025
  20. Elijah NewrenAug 26, 2025
  21. Junio C HamanoAug 26, 2025
  22. Patrick SteinhardtSep 2, 2025

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