improvement: add verifier for identity fields. (#626)

* improvement: adds verifier for identity fields.
---------

Co-authored-by: abhishek <abhishek.tripathi@tinymesh.in>

lib/ash/resource/dsl.ex

@@ -1332,7 +1332,8 @@ defmodule Ash.Resource.Dsl do
 
   @verifiers [
     Ash.Resource.Verifiers.ValidateRelationshipAttributesMatch,
-    Ash.Resource.Verifiers.VerifyReservedCalculationArguments
+    Ash.Resource.Verifiers.VerifyReservedCalculationArguments,
+    Ash.Resource.Verifiers.VerifyIdentityFields
   ]
 
   @moduledoc """

lib/ash/resource/verifiers/verfiy_identities.ex

@@ -0,0 +1,23 @@
+defmodule Ash.Resource.Verifiers.VerifyIdentityFields do
+  @moduledoc """
+  Raises an error on potentially incompatible identity attributes.
+  """
+  use Spark.Dsl.Verifier
+
+  def verify(dsl) do
+    identities = Ash.Resource.Info.identities(dsl)
+
+    for identity <- identities do
+      for key <- identity.keys do
+        if !Ash.Resource.Info.attribute(dsl, key) do
+          raise Spark.Error.DslError,
+            module: Spark.Dsl.Verifier.get_persisted(dsl, :module),
+            message: "All identity keys must be attributes. Got: #{inspect(key)}",
+            path: [:identities, identity.name]
+        end
+      end
+    end
+
+    :ok
+  end
+end

test/resource/identities_test.exs

@@ -69,5 +69,37 @@ defmodule Ash.Test.Resource.IdentitiesTest do
                %Ash.Resource.Identity{description: "require one of name/contents"}
              ] = Ash.Resource.Info.identities(Post)
     end
+
+    test "enforce identity constraints on attributes" do
+      assert_raise Spark.Error.DslError,
+                   ~r/All identity keys must be attributes. Got: :naem/,
+                   fn ->
+                     defmodule Site do
+                       @moduledoc false
+                       use Ash.Resource
+
+                       attributes do
+                         uuid_primary_key :id
+                         attribute :url, :string
+                       end
+                     end
+
+                     defposts do
+                       actions do
+                         read :read do
+                           primary? true
+                         end
+
+                         relationships do
+                           belongs_to :site, Site
+                         end
+                       end
+
+                       identities do
+                         identity :name_site, [:naem, :site]
+                       end
+                     end
+                   end
+    end
   end
 end