repo-settings: enable sparse index by default

There is some strangeness when expanding a sparse-index that exists
within a submodule. We will need to resolve that later, but for now,
let's do a better job of explicitly disabling the sparse-index when
requested, and do so in t7817.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>

repo-settings.c

@@ -74,7 +74,7 @@ void prepare_repo_settings(struct repository *r)
 	repo_cfg_bool(r, "fetch.writecommitgraph", &r->settings.fetch_write_commit_graph, 0);
 	repo_cfg_bool(r, "pack.usesparse", &r->settings.pack_use_sparse, 1);
 	repo_cfg_bool(r, "core.multipackindex", &r->settings.core_multi_pack_index, 1);
-	repo_cfg_bool(r, "index.sparse", &r->settings.sparse_index, 0);
+	repo_cfg_bool(r, "index.sparse", &r->settings.sparse_index, 1);
 
 	/*
 	 * The GIT_TEST_MULTI_PACK_INDEX variable is special in that

t/t1092-sparse-checkout-compatibility.sh

@@ -155,6 +155,7 @@ init_repos () {
 	git -C sparse-index reset --hard &&
 
 	# initialize sparse-checkout definitions
+	git -C sparse-checkout config index.sparse false &&
 	git -C sparse-checkout sparse-checkout init --cone &&
 	git -C sparse-checkout sparse-checkout set deep &&
 	git -C sparse-index sparse-checkout init --cone --sparse-index &&

t/t7817-grep-sparse-checkout.sh

@@ -49,7 +49,7 @@ test_expect_success 'setup' '
 		echo "text" >B/b &&
 		git add A B &&
 		git commit -m sub &&
-		git sparse-checkout init --cone &&
+		git sparse-checkout init --cone --no-sparse-index &&
 		git sparse-checkout set B
 	) &&