feat: add resource metadata to Ash.NotLoaded struct

lib/ash/actions/helpers.ex

@@ -1018,7 +1018,8 @@ defmodule Ash.Actions.Helpers do
       end
     end)
     |> Map.new(fn attribute ->
-      {attribute.name, %Ash.NotLoaded{field: attribute.name, type: :attribute}}
+      {attribute.name,
+       %Ash.NotLoaded{field: attribute.name, type: :attribute, resource: resource}}
     end)
   end
 

lib/ash/not_loaded.ex

@@ -4,24 +4,36 @@
 
 defmodule Ash.NotLoaded do
   @moduledoc "Used when a field hasn't been loaded or selected."
-  defstruct [:field, :type]
+  defstruct [:field, :type, :resource]
 
   @type t :: %__MODULE__{
           field: atom,
-          type: :relationship | :calculation | :aggregate | :attribute
+          type: :relationship | :calculation | :aggregate | :attribute,
+          resource: module | nil
         }
 
   defimpl Inspect do
     import Inspect.Algebra
 
     def inspect(not_loaded, opts) do
-      concat([
+      custom_options = Map.get(opts, :custom_options, [])
+      in_resource? = Keyword.get(custom_options, :in_resource?, false)
+      show_resource? = not is_nil(not_loaded.resource) and !in_resource?
+
+      container_doc(
         "#Ash.NotLoaded<",
-        to_doc(not_loaded.type, opts),
-        ", field: ",
-        to_doc(not_loaded.field, opts),
-        ">"
-      ])
+        [
+          to_doc(not_loaded.type, opts),
+          concat("field: ", to_doc(not_loaded.field, opts)),
+          or_empty(concat("resource: ", to_doc(not_loaded.resource, opts)), show_resource?)
+        ],
+        ">",
+        opts,
+        fn doc, _opts -> doc end
+      )
     end
+
+    defp or_empty(value, true), do: value
+    defp or_empty(_, false), do: empty()
   end
 end

lib/ash/resource.ex

@@ -232,6 +232,15 @@ defmodule Ash.Resource do
             fields = @show_fields -- subtract_fields
 
             fun = fn field, opts ->
+              custom_options = Map.get(opts, :custom_options, [])
+
+              opts =
+                Map.put(
+                  opts,
+                  :custom_options,
+                  Keyword.put(custom_options, :in_resource?, true)
+                )
+
               Inspect.List.keyword({field, Map.get(record, field)}, opts)
             end
 
@@ -618,8 +627,15 @@ defmodule Ash.Resource do
           Map.get(record, resource_calculation.name)
         else
           case Map.fetch(record.calculations, resource_calculation.name) do
-            {:ok, value} -> value
-            :error -> %Ash.NotLoaded{type: :calculation, field: resource_calculation.name}
+            {:ok, value} ->
+              value
+
+            :error ->
+              %Ash.NotLoaded{
+                type: :calculation,
+                field: resource_calculation.name,
+                resource: record.__struct__
+              }
           end
         end
 

lib/ash/resource/schema.ex

@@ -87,7 +87,12 @@ defmodule Ash.Schema do
               Module.put_attribute(
                 __MODULE__,
                 :ash_struct_fields,
-                {relationship.name, %Ash.NotLoaded{type: :relationship, field: relationship.name}}
+                {relationship.name,
+                 %Ash.NotLoaded{
+                   type: :relationship,
+                   field: relationship.name,
+                   resource: __MODULE__
+                 }}
               )
             end
 
@@ -110,7 +115,8 @@ defmodule Ash.Schema do
               Module.put_attribute(
                 __MODULE__,
                 :ash_struct_fields,
-                {aggregate.name, %Ash.NotLoaded{type: :aggregate, field: aggregate.name}}
+                {aggregate.name,
+                 %Ash.NotLoaded{type: :aggregate, field: aggregate.name, resource: __MODULE__}}
               )
             end
 
@@ -140,7 +146,8 @@ defmodule Ash.Schema do
               Module.put_attribute(
                 __MODULE__,
                 :ash_struct_fields,
-                {calculation.name, %Ash.NotLoaded{type: :calculation, field: calculation.name}}
+                {calculation.name,
+                 %Ash.NotLoaded{type: :calculation, field: calculation.name, resource: __MODULE__}}
               )
             end
 
@@ -258,7 +265,12 @@ defmodule Ash.Schema do
               Module.put_attribute(
                 __MODULE__,
                 :ash_struct_fields,
-                {relationship.name, %Ash.NotLoaded{type: :relationship, field: relationship.name}}
+                {relationship.name,
+                 %Ash.NotLoaded{
+                   type: :relationship,
+                   field: relationship.name,
+                   resource: __MODULE__
+                 }}
               )
             end
 
@@ -281,7 +293,8 @@ defmodule Ash.Schema do
               Module.put_attribute(
                 __MODULE__,
                 :ash_struct_fields,
-                {aggregate.name, %Ash.NotLoaded{type: :aggregate, field: aggregate.name}}
+                {aggregate.name,
+                 %Ash.NotLoaded{type: :aggregate, field: aggregate.name, resource: __MODULE__}}
               )
             end
 
@@ -311,7 +324,8 @@ defmodule Ash.Schema do
               Module.put_attribute(
                 __MODULE__,
                 :ash_struct_fields,
-                {calculation.name, %Ash.NotLoaded{type: :calculation, field: calculation.name}}
+                {calculation.name,
+                 %Ash.NotLoaded{type: :calculation, field: calculation.name, resource: __MODULE__}}
               )
             end
 

test/not_loaded_test.exs

@@ -0,0 +1,127 @@
+# SPDX-FileCopyrightText: 2019 ash contributors <https://github.com/ash-project/ash/graphs/contributors>
+#
+# SPDX-License-Identifier: MIT
+
+defmodule Ash.Test.NotLoadedTest do
+  @moduledoc false
+  use ExUnit.Case, async: true
+
+  defmodule Domain do
+    @moduledoc false
+    use Ash.Domain
+
+    resources do
+      allow_unregistered? true
+    end
+  end
+
+  defmodule Post do
+    @moduledoc false
+    use Ash.Resource,
+      domain: Domain,
+      data_layer: Ash.DataLayer.Ets
+
+    ets do
+      private?(true)
+    end
+
+    actions do
+      default_accept :*
+      defaults [:read, :destroy, create: :*, update: :*]
+    end
+
+    attributes do
+      uuid_primary_key :id
+      attribute :title, :string, public?: true
+      attribute :body, :string, public?: true
+    end
+
+    relationships do
+      belongs_to :author, __MODULE__, public?: true
+    end
+
+    calculations do
+      calculate :title_upcase, :string, expr(string_upcase(title)) do
+        public? true
+      end
+    end
+
+    aggregates do
+      count :count_of_related, :author, public?: true
+    end
+  end
+
+  describe "struct" do
+    test "resource field defaults to nil" do
+      not_loaded = %Ash.NotLoaded{type: :relationship, field: :author}
+      assert not_loaded.resource == nil
+    end
+
+    test "resource field can be set" do
+      not_loaded = %Ash.NotLoaded{type: :relationship, field: :author, resource: Post}
+      assert not_loaded.resource == Post
+    end
+  end
+
+  describe "resource in struct defaults" do
+    test "relationship fields have resource set in struct default" do
+      post = struct(Post)
+      assert %Ash.NotLoaded{resource: Post, type: :relationship} = post.author
+    end
+
+    test "aggregate fields have resource set in struct default" do
+      post = struct(Post)
+      assert %Ash.NotLoaded{resource: Post, type: :aggregate} = post.count_of_related
+    end
+
+    test "calculation fields have resource set in struct default" do
+      post = struct(Post)
+      assert %Ash.NotLoaded{resource: Post, type: :calculation} = post.title_upcase
+    end
+  end
+
+  describe "inspect" do
+    test "shows resource when inspected standalone" do
+      not_loaded = %Ash.NotLoaded{type: :relationship, field: :author, resource: Post}
+      result = inspect(not_loaded)
+      assert result =~ "resource:"
+      assert result =~ "Post"
+    end
+
+    test "omits resource when resource is nil" do
+      not_loaded = %Ash.NotLoaded{type: :relationship, field: :author}
+      result = inspect(not_loaded)
+      refute result =~ "resource:"
+    end
+
+    test "hides resource inside a record inspect" do
+      post = struct(Post)
+      result = inspect(post)
+      assert result =~ "NotLoaded"
+      refute result =~ "resource:"
+    end
+
+    test "hides resource when in_resource? custom option is set" do
+      not_loaded = %Ash.NotLoaded{type: :relationship, field: :author, resource: Post}
+      opts = %Inspect.Opts{custom_options: [in_resource?: true]}
+
+      result =
+        Inspect.Algebra.format(Inspect.inspect(not_loaded, opts), 80)
+        |> IO.iodata_to_binary()
+
+      refute result =~ "resource:"
+    end
+
+    test "shows resource when in_resource? is not set" do
+      not_loaded = %Ash.NotLoaded{type: :relationship, field: :author, resource: Post}
+      opts = %Inspect.Opts{}
+
+      result =
+        Inspect.Algebra.format(Inspect.inspect(not_loaded, opts), 80)
+        |> IO.iodata_to_binary()
+
+      assert result =~ "resource:"
+      assert result =~ "Post"
+    end
+  end
+end