From 0d3256065114e79ab12065db8669c058a08538dd Mon Sep 17 00:00:00 2001
From: Zach Daniel <zach@zachdaniel.dev>
Date: Fri, 9 Jun 2023 10:17:48 -0400
Subject: [PATCH] fix: pass empty select statement when loading on changesets
 fix: fixes for loading through attributes

---
 lib/ash/actions/helpers.ex | 14 ++++++++++++--
 lib/ash/actions/read.ex    | 24 +++++++++++-------------
 lib/ash/query/query.ex     | 15 +++++++++++++++
 lib/ash/type/type.ex       |  1 +
 4 files changed, 39 insertions(+), 15 deletions(-)

diff --git a/lib/ash/actions/helpers.ex b/lib/ash/actions/helpers.ex
index 186a401d..8a48f046 100644
--- a/lib/ash/actions/helpers.ex
+++ b/lib/ash/actions/helpers.ex
@@ -405,7 +405,12 @@ defmodule Ash.Actions.Helpers do
     if changeset.load in [nil, []] do
       {:ok, result, instructions}
     else
-      case api.load(result, changeset.load, opts) do
+      query =
+        changeset.resource
+        |> Ash.Query.select([])
+        |> Ash.Query.load(changeset.load)
+
+      case api.load(result, query, opts) do
         {:ok, result} ->
           {:ok, result, instructions}
 
@@ -419,7 +424,12 @@ defmodule Ash.Actions.Helpers do
     if changeset.load in [nil, []] do
       {:ok, result}
     else
-      case api.load(result, changeset.load, opts) do
+      query =
+        changeset.resource
+        |> Ash.Query.select([])
+        |> Ash.Query.load(changeset.load)
+
+      case api.load(result, query, opts) do
         {:ok, result} ->
           {:ok, result}
 
diff --git a/lib/ash/actions/read.ex b/lib/ash/actions/read.ex
index 000e87e0..bd52d967 100644
--- a/lib/ash/actions/read.ex
+++ b/lib/ash/actions/read.ex
@@ -402,13 +402,6 @@ defmodule Ash.Actions.Read do
                 else
                   data
                   |> Load.attach_loads(get_in(context, path ++ [:fetch, :load]) || %{})
-                  |> load_through_attributes(
-                    query,
-                    api,
-                    context[:actor],
-                    context[:tracer],
-                    context[:authorize?]
-                  )
                   |> add_aggregate_values(
                     fetched_data[:aggregates],
                     query.resource,
@@ -430,6 +423,13 @@ defmodule Ash.Actions.Read do
                     context[:tracer],
                     request_opts
                   )
+                  |> load_through_attributes(
+                    query,
+                    api,
+                    context[:actor],
+                    context[:tracer],
+                    context[:authorize?]
+                  )
                   |> case do
                     {:ok, values} ->
                       values
@@ -460,7 +460,9 @@ defmodule Ash.Actions.Read do
     [fetch, process]
   end
 
-  defp load_through_attributes(results, query, api, actor, tracer, authorize?) do
+  defp load_through_attributes({:requests, error}, _, _, _, _, _), do: {:requests, error}
+
+  defp load_through_attributes({:ok, results}, query, api, actor, tracer, authorize?) do
     Enum.reduce_while(query.load_through, {:ok, results}, fn
       {:calculation, load_through}, {:ok, results} ->
         Enum.reduce_while(load_through, {:ok, results}, fn {name, load_statement},
@@ -2938,12 +2940,8 @@ defmodule Ash.Actions.Read do
     end
   end
 
-  defp add_aggregate_values({:error, error}, _, _, _, _) do
-    {:error, error}
-  end
-
   defp add_aggregate_values(
-         {:ok, results},
+         results,
          aggregates,
          resource,
          aggregate_values,
diff --git a/lib/ash/query/query.ex b/lib/ash/query/query.ex
index 239099d6..b519664e 100644
--- a/lib/ash/query/query.ex
+++ b/lib/ash/query/query.ex
@@ -114,6 +114,21 @@ defmodule Ash.Query do
     import Inspect.Algebra
 
     def inspect(query, opts) do
+      load_through_attributes = Map.to_list(query.load_through[:attributes] || %{})
+
+      query = %{
+        query
+        | load: Keyword.merge(query.load || [], load_through_attributes),
+          calculations:
+            Map.new(query.calculations, fn {name, calc} ->
+              if load_through = query.load_through[:calculations][name] do
+                {name, {calc, load_through}}
+              else
+                {name, calc}
+              end
+            end)
+      }
+
       sort? = query.sort != []
       load? = query.load != []
       aggregates? = query.aggregates != %{}
diff --git a/lib/ash/type/type.ex b/lib/ash/type/type.ex
index 777862cf..497aba4c 100644
--- a/lib/ash/type/type.ex
+++ b/lib/ash/type/type.ex
@@ -837,6 +837,7 @@ defmodule Ash.Type do
 
   def splicing_nil_values(values, callback) when is_list(values) do
     values
+    |> Stream.flat_map(&List.wrap/1)
     |> Stream.with_index()
     |> Enum.reduce({[], []}, fn
       {nil, index}, {acc, nil_indices} ->