From 548247a8b753d9172a4592eefce4b27111aff19d Mon Sep 17 00:00:00 2001
From: Darren Black <dblack@totaltrash.net>
Date: Tue, 23 Aug 2022 00:41:25 +1000
Subject: [PATCH] fix: False default value for argument is nil in changeset
 (#364)

---
 lib/ash/changeset/changeset.ex    |  6 +++++-
 test/changeset/changeset_test.exs | 19 +++++++++++++++++++
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/lib/ash/changeset/changeset.ex b/lib/ash/changeset/changeset.ex
index 148270f4..31892259 100644
--- a/lib/ash/changeset/changeset.ex
+++ b/lib/ash/changeset/changeset.ex
@@ -1400,7 +1400,11 @@ defmodule Ash.Changeset do
   @doc "Gets the value of an argument provided to the changeset"
   @spec get_argument(t, atom) :: term
   def get_argument(changeset, argument) when is_atom(argument) do
-    Map.get(changeset.arguments, argument) || Map.get(changeset.arguments, to_string(argument))
+    if Map.has_key?(changeset.arguments, argument) do
+      Map.get(changeset.arguments, argument)
+    else
+      Map.get(changeset.arguments, to_string(argument))
+    end
   end
 
   @doc "fetches the value of an argument provided to the changeset or `:error`"
diff --git a/test/changeset/changeset_test.exs b/test/changeset/changeset_test.exs
index 2bcdbd64..8d8b6fdf 100644
--- a/test/changeset/changeset_test.exs
+++ b/test/changeset/changeset_test.exs
@@ -25,6 +25,16 @@ defmodule Ash.Test.Changeset.ChangesetTest do
           allow_nil? false
         end
 
+        argument :false_optional_argument, :boolean do
+          allow_nil? false
+          default false
+        end
+
+        argument :true_optional_argument, :boolean do
+          allow_nil? false
+          default true
+        end
+
         validate confirm(:name, :confirm_name)
       end
     end
@@ -855,6 +865,15 @@ defmodule Ash.Test.Changeset.ChangesetTest do
         |> Api.create!(action: :create_with_confirmation)
       end
     end
+
+    test "optional arguments should use the default" do
+      changeset =
+        Category
+        |> Changeset.for_create(:create_with_confirmation)
+
+      assert Changeset.get_argument(changeset, :true_optional_argument) == true
+      assert Changeset.get_argument(changeset, :false_optional_argument) == false
+    end
   end
 
   describe "for_<action>" do