From 83d0e05bdc5ed1db545576a1729a27f1d39c8836 Mon Sep 17 00:00:00 2001
From: Zach Daniel <zach@zachdaniel.dev>
Date: Tue, 14 Feb 2023 16:26:31 -0500
Subject: [PATCH] fix: handle cases where union type is already atom

---
 lib/ash/type/union.ex | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/lib/ash/type/union.ex b/lib/ash/type/union.ex
index ac9c4d89..e39222be 100644
--- a/lib/ash/type/union.ex
+++ b/lib/ash/type/union.ex
@@ -254,7 +254,13 @@ defmodule Ash.Type.Union do
   def cast_stored(nil, _), do: {:ok, nil}
 
   def cast_stored(%{"type" => type, "value" => value}, constraints) do
-    type = String.to_existing_atom(type)
+    type =
+      if is_binary(type) do
+        String.to_existing_atom(type)
+      else
+        type
+      end
+
     types = constraints[:types] || []
 
     case Keyword.fetch(types, type) do