diff --git a/builtin/index-pack.c b/builtin/index-pack.c
index d967d188a3..f176dd28c8 100644
--- a/builtin/index-pack.c
+++ b/builtin/index-pack.c
@@ -1368,9 +1368,8 @@ static void fix_unresolved_deltas(struct hashfile *f)
 				continue;
 			oid_array_append(&to_fetch, &d->oid);
 		}
-		if (to_fetch.nr)
-			promisor_remote_get_direct(the_repository,
-						   to_fetch.oid, to_fetch.nr);
+		promisor_remote_get_direct(the_repository,
+					   to_fetch.oid, to_fetch.nr);
 		oid_array_clear(&to_fetch);
 	}
 
diff --git a/diff.c b/diff.c
index f2cfbf2214..d0f8032456 100644
--- a/diff.c
+++ b/diff.c
@@ -6517,12 +6517,11 @@ void diffcore_std(struct diff_options *options)
 			add_if_missing(options->repo, &to_fetch, p->one);
 			add_if_missing(options->repo, &to_fetch, p->two);
 		}
-		if (to_fetch.nr)
-			/*
-			 * NEEDSWORK: Consider deduplicating the OIDs sent.
-			 */
-			promisor_remote_get_direct(options->repo,
-						   to_fetch.oid, to_fetch.nr);
+		/*
+		 * NEEDSWORK: Consider deduplicating the OIDs sent.
+		 */
+		promisor_remote_get_direct(options->repo,
+					   to_fetch.oid, to_fetch.nr);
 		oid_array_clear(&to_fetch);
 	}
 
diff --git a/promisor-remote.c b/promisor-remote.c
index 9f338c945f..2155dfe657 100644
--- a/promisor-remote.c
+++ b/promisor-remote.c
@@ -241,6 +241,9 @@ int promisor_remote_get_direct(struct repository *repo,
 	int to_free = 0;
 	int res = -1;
 
+	if (oid_nr == 0)
+		return 0;
+
 	promisor_remote_init();
 
 	for (r = promisors; r; r = r->next) {
diff --git a/promisor-remote.h b/promisor-remote.h
index 737bac3a33..6343c47d18 100644
--- a/promisor-remote.h
+++ b/promisor-remote.h
@@ -20,6 +20,14 @@ struct promisor_remote {
 void promisor_remote_reinit(void);
 struct promisor_remote *promisor_remote_find(const char *remote_name);
 int has_promisor_remote(void);
+
+/*
+ * Fetches all requested objects from all promisor remotes, trying them one at
+ * a time until all objects are fetched. Returns 0 upon success, and non-zero
+ * otherwise.
+ *
+ * If oid_nr is 0, this function returns 0 (success) immediately.
+ */
 int promisor_remote_get_direct(struct repository *repo,
 			       const struct object_id *oids,
 			       int oid_nr);
diff --git a/unpack-trees.c b/unpack-trees.c
index 1ecdab3304..01c9149121 100644
--- a/unpack-trees.c
+++ b/unpack-trees.c
@@ -422,9 +422,8 @@ static int check_updates(struct unpack_trees_options *o)
 				continue;
 			oid_array_append(&to_fetch, &ce->oid);
 		}
-		if (to_fetch.nr)
-			promisor_remote_get_direct(the_repository,
-						   to_fetch.oid, to_fetch.nr);
+		promisor_remote_get_direct(the_repository,
+					   to_fetch.oid, to_fetch.nr);
 		oid_array_clear(&to_fetch);
 	}
 	for (i = 0; i < index->cache_nr; i++) {