On 5/17/2021 9:33 PM, Elijah Newren wrote: > On Fri, May 14, 2021 at 11:31 AM Derrick Stolee via GitGitGadget > <gitgitgadget@xxxxxxxxx> wrote: >> >> From: Derrick Stolee <dstolee@xxxxxxxxxxxxx> >> >> When creating a full index from a sparse one, we create cache entries >> for every blob within a given sparse directory entry. These are >> correctly marked with the CE_SKIP_WORKTREE flag, but they must also be >> marked with the CE_EXTENDED flag to ensure that the skip-worktree bit is >> correctly written to disk in the case that the index is not converted >> back down to a sparse-index. > > This seems odd to me. When sparse-index is not involved and we are > just doing simple sparse checkouts, do we mark CE_SKIP_WORKTREE > entries with CE_EXTENDED? I can't find any code that does so. > > Is it possible that the setting of CE_EXTENDED is just a workaround > that happens to force the index to be written in cases where the logic > is otherwise thinking it can get away without one? Or is there > something I'm missing about why the CE_EXTENDED flag is actually > needed here? This is happening within the context of ensure_full_index(), so we are creating new cache entries and want to mimic what they would look like on-disk. Something within do_write_index() discovers that since CE_SKIP_WORKTREE is set, then also CE_EXTENDED should be set in order to ensure that the on-disk representation has enough room for the CE_SKIP_WORKTREE bit. I suppose this might not have a meaningful purpose other than when I compare a full index against an expanded sparse-index and check if their flags match. Thanks, -Stolee
