On 8/17/2021 9:23 AM, Derrick Stolee via GitGitGadget wrote:
> From: Derrick Stolee <dstolee@xxxxxxxxxxxxx>
>
> The convert_to_sparse() method checks for the GIT_TEST_SPARSE_INDEX
> environment variable or the "index.sparse" config setting before
> converting the index to a sparse one. This is for ease of use since all
> current consumers are preparing to compress the index before writing it
> to disk. If these settings are not enabled, then convert_to_sparse()
> silently returns without doing anything.
>
> We will add a consumer in the next change that wants to use the sparse
> index as an in-memory data structure, regardless of whether the on-disk
> format should be sparse.
>
> To that end, create the SPARSE_INDEX_IGNORE_CONFIG flag that will skip
> these config checks when enabled. All current consumers are modified to
> pass '0' in the new 'flags' parameter.
...
> -int convert_to_sparse(struct index_state *istate)
> +int convert_to_sparse(struct index_state *istate, int flags)
> {
> int test_env;
>
> @@ -135,20 +135,22 @@ int convert_to_sparse(struct index_state *istate)
> if (!istate->repo)
> istate->repo = the_repository;
>
Above this hunk, we fail automatically if the index has a split index.
The purpose of this flag is instead to say "convert to sparse for the
purpose of in-memory computations, not for writing to disk". For such
a case, we could move the split index check to be within the hunk
below. It would be appropriate to rename the flag to something like
SPARSE_INDEX_IN_MEMORY or SPARSE_INDEX_NO_DISK_WRITE to make the
intention more clear.
Thanks to SZEDER for pointing out this failure. I will fix it in the
next version.
> - /*
> - * The GIT_TEST_SPARSE_INDEX environment variable triggers the
> - * index.sparse config variable to be on.
> - */
> - test_env = git_env_bool("GIT_TEST_SPARSE_INDEX", -1);
> - if (test_env >= 0)
> - set_sparse_index_config(istate->repo, test_env);
> + if (!(flags & SPARSE_INDEX_IGNORE_CONFIG)) {
> + /*
> + * The GIT_TEST_SPARSE_INDEX environment variable triggers the
> + * index.sparse config variable to be on.
> + */
> + test_env = git_env_bool("GIT_TEST_SPARSE_INDEX", -1);
> + if (test_env >= 0)
> + set_sparse_index_config(istate->repo, test_env);
>
> - /*
> - * Only convert to sparse if index.sparse is set.
> - */
> - prepare_repo_settings(istate->repo);
> - if (!istate->repo->settings.sparse_index)
> - return 0;
> + /*
> + * Only convert to sparse if index.sparse is set.
> + */
> + prepare_repo_settings(istate->repo);
> + if (!istate->repo->settings.sparse_index)
> + return 0;
> + }
If you want to try this, here is a diff that can help:
--- >8 ---
diff --git a/builtin/sparse-checkout.c b/builtin/sparse-checkout.c
index b06c8f885ac..c6a512a2107 100644
--- a/builtin/sparse-checkout.c
+++ b/builtin/sparse-checkout.c
@@ -131,7 +131,7 @@ static void clean_tracked_sparse_directories(struct repository *r)
* prevents us from converting to a sparse index, then do
* not try deleting files.
*/
- if (convert_to_sparse(r->index, SPARSE_INDEX_IGNORE_CONFIG))
+ if (convert_to_sparse(r->index, SPARSE_INDEX_MEMORY_ONLY))
return;
was_full = 1;
}
diff --git a/sparse-index.c b/sparse-index.c
index e0a854f9fc3..267503b21fa 100644
--- a/sparse-index.c
+++ b/sparse-index.c
@@ -128,14 +128,20 @@ int convert_to_sparse(struct index_state *istate, int flags)
{
int test_env;
- if (istate->split_index || istate->sparse_index || !istate->cache_nr ||
+ if (istate->sparse_index || !istate->cache_nr ||
!core_apply_sparse_checkout || !core_sparse_checkout_cone)
return 0;
if (!istate->repo)
istate->repo = the_repository;
- if (!(flags & SPARSE_INDEX_IGNORE_CONFIG)) {
+ if (!(flags & SPARSE_INDEX_MEMORY_ONLY)) {
+ /*
+ * The sparse index is not integrated with a split index.
+ */
+ if (istate->sparse_index)
+ return 0;
+
/*
* The GIT_TEST_SPARSE_INDEX environment variable triggers the
* index.sparse config variable to be on.
diff --git a/sparse-index.h b/sparse-index.h
index 475f4f0f8da..9f3d7bc7faf 100644
--- a/sparse-index.h
+++ b/sparse-index.h
@@ -2,7 +2,7 @@
#define SPARSE_INDEX_H__
struct index_state;
-#define SPARSE_INDEX_IGNORE_CONFIG (1 << 0)
+#define SPARSE_INDEX_MEMORY_ONLY (1 << 0)
int convert_to_sparse(struct index_state *istate, int flags);
/*
--- >8 ---
Thanks,
-Stolee
