On Mon, Jun 21, 2021 at 06:25:18PM -0400, Taylor Blau wrote: > When writing a new multi-pack index, write_midx_internal() attempts to > load any existing one to fill in some pieces of information. But it uses > load_multi_pack_index(), which ignores the configuration > "core.multiPackIndex", which indicates whether or not Git is allowed to > read an existing multi-pack-index. > > Replace this with a routine that does respect that setting, to avoid > reading multi-pack-index files when told not to. > > This avoids a problem that would arise in subsequent patches due to the > combination of 'git repack' reopening the object store in-process and > the multi-pack index code not checking whether a pack already exists in > the object store when calling add_pack_to_midx(). > > This would ultimately lead to a cycle being created along the > 'packed_git' struct's '->next' pointer. That is obviously bad, but it > has hard-to-debug downstream effects like saying a bitmap can't be > loaded for a pack because one already exists (for the same pack). I'm not sure I completely understand the bug that this causes. But another question: does this impact how git -c core.multipackindex=false multi-pack-index write behaves? I.e., do we still write, but just avoid reading the existing midx? That itself seems like a more sensible behavior (e.g., trying to recover from a broken midx state). -Peff
