fix: don’t require multitenancy attribute in get (#1716)

Signed-off-by: Adam Tharani <adamtharani@me.com>

lib/ash/filter/filter.ex

@@ -471,6 +471,18 @@ defmodule Ash.Filter do
         end
 
       {fields, value} ->
+        multitenancy_attribute = Ash.Resource.Info.multitenancy_attribute(resource)
+        fields = Enum.reject(fields, fn key -> key == multitenancy_attribute end)
+
+        {keyval?, value} =
+          case fields do
+            [field] when not keyval? ->
+              {true, [{field, value}]}
+
+            _ ->
+              {keyval?, value}
+          end
+
         if keyval? do
           with :error <- get_keys(value, fields, resource),
                :error <- get_identity_filter(resource, id) do

test/filter/multitenancy_test.exs

@@ -0,0 +1,62 @@
+defmodule Ash.Test.MultitenancyTest do
+  @moduledoc false
+  use ExUnit.Case, async: true
+
+  alias Ash.Test.Domain, as: Domain
+
+  defmodule MultiTenant do
+    use Ash.Resource, domain: Domain, data_layer: Ash.DataLayer.Ets
+
+    multitenancy do
+      strategy :attribute
+      attribute :owner
+    end
+
+    attributes do
+      attribute :id, :integer, primary_key?: true, allow_nil?: false, public?: true
+      attribute :owner, :integer, primary_key?: true, allow_nil?: false, public?: true
+    end
+
+    actions do
+      default_accept :*
+      defaults [:read, :create]
+    end
+  end
+
+  test "reading an object doesn't require multitenancy attribute in the primary key" do
+    MultiTenant
+    |> Ash.Changeset.for_create(:create, %{id: 1000, owner: 1})
+    |> Ash.create!(tenant: 1)
+
+    MultiTenant
+    |> Ash.get!(1000, tenant: 1)
+  end
+
+  defmodule NonMultiTenant do
+    use Ash.Resource, domain: Domain, data_layer: Ash.DataLayer.Ets
+
+    attributes do
+      attribute :id, :integer, primary_key?: true, allow_nil?: false, public?: true
+      attribute :owner, :integer, primary_key?: true, allow_nil?: false, public?: true
+    end
+
+    actions do
+      default_accept :*
+      defaults [:read, :create]
+    end
+  end
+
+  test "reading an object without multitenancy requires attribute in the primary key" do
+    NonMultiTenant
+    |> Ash.Changeset.for_create(:create, %{id: 1000, owner: 1})
+    |> Ash.create!()
+
+    ExUnit.Assertions.assert_raise(Ash.Error.Invalid, fn ->
+      NonMultiTenant
+      |> Ash.get!(1000)
+    end)
+
+    NonMultiTenant
+    |> Ash.get!(%{id: 1000, owner: 1})
+  end
+end