update-index: remove sparse index expansion for --cacheinfo

Rearrange `add_index_entry_with_check` to allow `index_name_stage_pos` to
expand the index _before_ attempting to invalidate the relevant cache tree
path. This permits implicit index expansion when adding a cache entry
outside the sparse checkout definition.

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

Author: vdye

builtin/update-index.c

@@ -426,10 +426,6 @@ static int add_cacheinfo(unsigned int mode, const struct object_id *oid,
 		ce->ce_flags |= CE_VALID;
 	option = allow_add ? ADD_CACHE_OK_TO_ADD : 0;
 	option |= allow_replace ? ADD_CACHE_OK_TO_REPLACE : 0;
-
-	/* TODO: ensure full index to maintain expected behavior */
-	ensure_full_index(&the_index);
-
 	if (add_cache_entry(ce, option))
 		return error("%s: cannot add to the index - missing --add option?",
 			     path);

read-cache.c

@@ -1324,9 +1324,6 @@ static int add_index_entry_with_check(struct index_state *istate, struct cache_e
 	int skip_df_check = option & ADD_CACHE_SKIP_DFCHECK;
 	int new_only = option & ADD_CACHE_NEW_ONLY;
 
-	if (!(option & ADD_CACHE_KEEP_CACHE_TREE))
-		cache_tree_invalidate_path(istate, ce->name);
-
 	/*
 	 * If this entry's path sorts after the last entry in the index,
 	 * we can avoid searching for it.
@@ -1337,6 +1334,13 @@ static int add_index_entry_with_check(struct index_state *istate, struct cache_e
 	else
 		pos = index_name_stage_pos(istate, ce->name, ce_namelen(ce), ce_stage(ce));
 
+	/*
+	 * Cache tree path should be invalidated only after index_name_stage_pos,
+	 * in case it expands a sparse index.
+	 */
+	if (!(option & ADD_CACHE_KEEP_CACHE_TREE))
+		cache_tree_invalidate_path(istate, ce->name);
+
 	/* existing match? Just replace it. */
 	if (pos >= 0) {
 		if (!new_only)