On Mon, Jan 25, 2021 at 9:42 AM Derrick Stolee via GitGitGadget
<gitgitgadget@xxxxxxxxx> wrote:
>
> From: Derrick Stolee <dstolee@xxxxxxxxxxxxx>
>
> The next change will translate full indexes into sparse indexes at write
> time. The existing logic provides a way for every sparse index to be
> expanded to a full index at read time. However, there are cases where an
> index is written and then continues to be used in-memory to perform
> further updates.
>
> unpack_trees() is frequently called after such a write. In particular,
> commands like 'git reset' do this double-update of the index.
>
> Ensure that we have a full index when entering unpack_trees(), but only
> when command_requires_full_index is true. This is always true at the
> moment, but we will later relax that after unpack_trees() is updated to
> handle sparse directory entries.
>
> Signed-off-by: Derrick Stolee <dstolee@xxxxxxxxxxxxx>
> ---
> unpack-trees.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/unpack-trees.c b/unpack-trees.c
> index f5f668f532d..4dd99219073 100644
> --- a/unpack-trees.c
> +++ b/unpack-trees.c
> @@ -1567,6 +1567,7 @@ static int verify_absent(const struct cache_entry *,
> */
> int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options *o)
> {
> + struct repository *repo = the_repository;
> int i, ret;
> static struct cache_entry *dfc;
> struct pattern_list pl;
> @@ -1578,6 +1579,12 @@ int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options
> trace_performance_enter();
> trace2_region_enter("unpack_trees", "unpack_trees", the_repository);
>
> + prepare_repo_settings(repo);
> + if (repo->settings.command_requires_full_index) {
> + ensure_full_index(o->src_index);
> + ensure_full_index(o->dst_index);
I was worried about o->result as well, since there is a
memset(&o->result, 0, sizeof(o->result));
followed by manually initializing the relevant fields of the
index_state. However, the relevant field here is your new
sparse_index bit, and you want that to be 0, i.e. full.
I also checked ensure_full_index() since it is often the case that
o->src_index == o->dst_index, but it'll be safe to be called twice on
the same index state -- at least as currently written.
So, this patch seems good.
> + }
> +
> if (!core_apply_sparse_checkout || !o->update)
> o->skip_sparse_checkout = 1;
> if (!o->skip_sparse_checkout && !o->pl) {
> --
> gitgitgadget
