stash: integrate with sparse index

Most of the functionality of `git stash` exists in already-sparse aware
subcommands, so enabling sparse index in `cmd_stash` allows the index to remain
sparse in most usages of `git stash`. Tests added to `t1092` reflect
commonly-used commands that are already sparse index-compatible.

Signed-off-by: Victoria Dye <[email protected]>

Author: vdye

builtin/stash.c

@@ -1703,6 +1703,9 @@ int cmd_stash(int argc, const char **argv, const char *prefix)
 	argc = parse_options(argc, argv, prefix, options, git_stash_usage,
 			     PARSE_OPT_KEEP_UNKNOWN | PARSE_OPT_KEEP_DASHDASH);
 
+	prepare_repo_settings(the_repository);
+	the_repository->settings.command_requires_full_index = 0;
+
 	index_file = get_index_file();
 	strbuf_addf(&stash_index_path, "%s.stash.%" PRIuMAX, index_file,
 		    (uintmax_t)pid);

t/t1092-sparse-checkout-compatibility.sh

@@ -1159,6 +1159,16 @@ test_expect_success 'sparse-index is not expanded' '
 	echo >>sparse-index/untracked.txt &&
 	ensure_not_expanded add . &&
 
+	echo >>sparse-index/a &&
+	ensure_not_expanded stash &&
+	ensure_not_expanded stash list &&
+	ensure_not_expanded stash show stash@{0} &&
+	ensure_not_expanded stash drop stash@{0} &&
+
+	ensure_not_expanded stash create &&
+	oid=$(git -C sparse-index stash create) &&
+	ensure_not_expanded stash store -m "test" $oid &&
+	ensure_not_expanded reset --hard &&
 	ensure_not_expanded checkout-index -f a &&
 	ensure_not_expanded checkout-index -f --all &&
 	for ref in update-deep update-folder1 update-folder2 update-deep