improvement: handle UUID types better

lib/expr.ex

@@ -662,16 +662,15 @@ defmodule AshPostgres.Expr do
 
   defp do_dynamic_expr(
          query,
-         %Type{arguments: [arg1, arg2, constraints]} = type_expr,
+         %Type{arguments: [arg1, arg2, constraints]},
          bindings,
-         _embedded?,
+         embedded?,
          _type
        ) do
-    arg1 = do_dynamic_expr(query, arg1, bindings, false)
+    arg2 = Ash.Type.get_type(arg2)
+    arg1 = maybe_uuid_to_binary(arg2, arg1, arg1)
     type = AshPostgres.Types.parameterized_type(arg2, constraints)
-    validate_type!(query, type, type_expr)
-
-    Ecto.Query.dynamic(type(^arg1, ^type))
+    do_dynamic_expr(query, arg1, bindings, embedded?, type)
   end
 
   defp do_dynamic_expr(
@@ -795,10 +794,29 @@ defmodule AshPostgres.Expr do
 
   defp do_dynamic_expr(query, value, _bindings, false, type) do
     value = maybe_sanitize_list(value)
+    type = AshPostgres.Types.parameterized_type(type, [])
     validate_type!(query, type, value)
+
     Ecto.Query.dynamic(type(^value, ^type))
   end
 
+  defp maybe_uuid_to_binary({:array, type}, value, _original_value) when is_list(value) do
+    Enum.map(value, &maybe_uuid_to_binary(type, &1, &1))
+  end
+
+  defp maybe_uuid_to_binary(type, value, original_value)
+       when type in [
+              Ash.Type.UUID.EctoType,
+              :uuid
+            ] and is_binary(value) do
+    case Ecto.UUID.dump(value) do
+      {:ok, encoded} -> encoded
+      _ -> original_value
+    end
+  end
+
+  defp maybe_uuid_to_binary(_type, _value, original_value), do: original_value
+
   defp validate_type!(query, type, context) do
     case type do
       {:parameterized, Ash.Type.CiStringWrapper.EctoType, _} ->

priv/resource_snapshots/test_repo/post_links/20221017133955.json

@@ -0,0 +1,77 @@
+{
+  "attributes": [
+    {
+      "allow_nil?": false,
+      "default": "nil",
+      "generated?": false,
+      "primary_key?": true,
+      "references": {
+        "destination_attribute": "id",
+        "destination_attribute_default": null,
+        "destination_attribute_generated": null,
+        "multitenancy": {
+          "attribute": null,
+          "global": null,
+          "strategy": null
+        },
+        "name": "post_links_source_post_id_fkey",
+        "on_delete": null,
+        "on_update": null,
+        "schema": "public",
+        "table": "posts"
+      },
+      "size": null,
+      "source": "source_post_id",
+      "type": "uuid"
+    },
+    {
+      "allow_nil?": false,
+      "default": "nil",
+      "generated?": false,
+      "primary_key?": true,
+      "references": {
+        "destination_attribute": "id",
+        "destination_attribute_default": null,
+        "destination_attribute_generated": null,
+        "multitenancy": {
+          "attribute": null,
+          "global": null,
+          "strategy": null
+        },
+        "name": "post_links_destination_post_id_fkey",
+        "on_delete": null,
+        "on_update": null,
+        "schema": "public",
+        "table": "posts"
+      },
+      "size": null,
+      "source": "destination_post_id",
+      "type": "uuid"
+    }
+  ],
+  "base_filter": null,
+  "check_constraints": [],
+  "custom_indexes": [],
+  "custom_statements": [],
+  "has_create_action": true,
+  "hash": "D5A5182C6A632C61F04477975186F608E1B6FA336CE6DAF40DBEF8A4E5689DB4",
+  "identities": [
+    {
+      "base_filter": null,
+      "index_name": "post_links_unique_link_index",
+      "keys": [
+        "source_post_id",
+        "destination_post_id"
+      ],
+      "name": "unique_link"
+    }
+  ],
+  "multitenancy": {
+    "attribute": null,
+    "global": null,
+    "strategy": null
+  },
+  "repo": "Elixir.AshPostgres.TestRepo",
+  "schema": null,
+  "table": "post_links"
+}

priv/test_repo/migrations/20221017133955_migrate_resources3.exs

@@ -0,0 +1,21 @@
+defmodule AshPostgres.TestRepo.Migrations.MigrateResources3 do
+  @moduledoc """
+  Updates resources based on their most recent snapshots.
+
+  This file was autogenerated with `mix ash_postgres.generate_migrations`
+  """
+
+  use Ecto.Migration
+
+  def up do
+    create unique_index(:post_links, [:source_post_id, :destination_post_id],
+             name: "post_links_unique_link_index"
+           )
+  end
+
+  def down do
+    drop_if_exists unique_index(:post_links, [:source_post_id, :destination_post_id],
+                     name: "post_links_unique_link_index"
+                   )
+  end
+end

test/type_test.exs

@@ -27,4 +27,12 @@ defmodule AshPostgres.Test.TypeTest do
              |> Ash.Query.filter(fragment("(?)[1] > (?)[2]", point, point))
              |> Api.read!()
   end
+
+  test "uuids can be used as strings in fragments" do
+    uuid = Ash.UUID.generate()
+
+    Post
+    |> Ash.Query.filter(fragment("? = ?", id, type(^uuid, :uuid)))
+    |> Api.read!()
+  end
 end