diff --git a/sha1-name.c b/sha1-name.c
index 6dda2c16df..cfe5c874b6 100644
--- a/sha1-name.c
+++ b/sha1-name.c
@@ -442,6 +442,18 @@ static enum get_oid_result get_short_oid(const char *name, int len,
 	find_short_packed_object(&ds);
 	status = finish_object_disambiguation(&ds, oid);
 
+	/*
+	 * If we didn't find it, do the usual reprepare() slow-path,
+	 * since the object may have recently been added to the repository
+	 * or migrated from loose to packed.
+	 */
+	if (status == MISSING_OBJECT) {
+		reprepare_packed_git(the_repository);
+		find_short_object_filename(&ds);
+		find_short_packed_object(&ds);
+		status = finish_object_disambiguation(&ds, oid);
+	}
+
 	if (!quietly && (status == SHORT_NAME_AMBIGUOUS)) {
 		struct oid_array collect = OID_ARRAY_INIT;
 
diff --git a/t/t3429-rebase-edit-todo.sh b/t/t3429-rebase-edit-todo.sh
index 862f229c87..76f6d306ea 100755
--- a/t/t3429-rebase-edit-todo.sh
+++ b/t/t3429-rebase-edit-todo.sh
@@ -11,7 +11,7 @@ test_expect_success 'rebase exec modifies rebase-todo' '
 	test -e F
 '
 
-test_expect_failure SHA1 'loose object cache vs re-reading todo list' '
+test_expect_success SHA1 'loose object cache vs re-reading todo list' '
 	GIT_REBASE_TODO=.git/rebase-merge/git-rebase-todo &&
 	export GIT_REBASE_TODO &&
 	write_script append-todo.sh <<-\EOS &&