On Tue, Mar 30, 2021 at 2:31 PM Derrick Stolee <stolee@xxxxxxxxx> wrote: > > On 3/30/2021 4:11 PM, Junio C Hamano wrote: > > "Derrick Stolee via GitGitGadget" <gitgitgadget@xxxxxxxxx> writes: > > > >> @@ repo-settings.c: void prepare_repo_settings(struct repository *r) > >> + * Initialize this as off. > >> + */ > >> + r->settings.sparse_index = 0; > >> -+ if (!repo_config_get_bool(r, "extensions.sparseindex", &value) && value) > >> ++ if (!repo_config_get_bool(r, "index.sparse", &value) && value) > >> + r->settings.sparse_index = 1; > >> } > > > > It would be helpful to have a way for the repository owner to say > > "Even if the version of Git may be capable of handling 'sdir' > > extension, and my checkout uses sparse-cone settings, I do not want > > to use it", and the other way around, i.e. "Even if my checkout > > currently does not use sparse-cone settings, do use 'sdir' > > extension". But for that, .sparse_index member may need to be > > tristate (i.e. forbidden, enable-if-needed, use-even-unneeded)? > > I believe as presented, index.sparse=false will prevent the sdir > extension from being used. If index.sparse=true, then it will only > be used if sparse-checkout is enabled in cone mode. > > I don't see the value in using the 'sdir' extension when not using > sparse-checkout in cone mode (and hence there are no sparse directory > entries in the index). What am I missing? > > > We have a similar setting in index.version; I believe we always > > auto-demote 3 down to 2 when extended flags are not used, and > > I think "always auto-demote" would be sufficient (iow, > > "use-even-unneeded" may not be necessary, even though that might > > help debugging). > > Yes, the same is happening here: we auto-demote to not use 'sdir' > if it the other settings are not configured as well. > > There is the rare scenario where these things all occur: > > 1. index.sparse = true > 2. core.sparseCheckout = true > 3. core.sparseCheckoutCone = true > 4. Every path in the index matches the cone-mode patterns. > > In this case, convert_to_sparse() is called and the istate->sparse > bit is set, telling do_write_index() to add the 'sdir' extension. > > This seems like a rare occurrence. Is it still worth adding logic > to avoid 'sdir' when these are all true? I'd agree that this would be very rare; probably indicative of someone either having a bug in their sparsity patterns or making a simplistic testcase to see how things operate.
