fix: load by __order__ ascending

lib/data_layer.ex

@@ -585,7 +585,7 @@ defmodule AshPostgres.DataLayer do
 
           from(row in subquery(query_with_order),
             select: row,
-            order_by: row.__order__
+            order_by: [asc: row.__order__]
           )
         else
           order_by = %{query.windows[:order] | expr: query.windows[:order].expr[:order_by]}
@@ -818,7 +818,7 @@ defmodule AshPostgres.DataLayer do
              where: field(source, ^source_attribute) in ^source_values,
              inner_lateral_join: destination in ^subquery,
              on: field(source, ^source_attribute) == field(destination, ^destination_attribute),
-             order_by: destination.__order__,
+             order_by: [asc: destination.__order__],
              select: destination,
              distinct: true
            )}
@@ -926,7 +926,7 @@ defmodule AshPostgres.DataLayer do
                  where: field(source, ^source_attribute) in ^source_values,
                  inner_lateral_join: destination in ^subquery,
                  select: destination,
-                 order_by: destination.__order__,
+                 order_by: [asc: destination.__order__],
                  distinct: true
                )}
             else

test/aggregate_test.exs

@@ -281,6 +281,60 @@ defmodule AshPostgres.AggregateTest do
                |> Ash.Query.sort(:first_comment)
                |> Api.read_one!()
     end
+
+    test "it can be sorted on and produces the appropriate order" do
+      post1 =
+        Post
+        |> Ash.Changeset.new(%{title: "title"})
+        |> Api.create!()
+
+      Comment
+      |> Ash.Changeset.new(%{title: "b"})
+      |> Ash.Changeset.manage_relationship(:post, post1, type: :append_and_remove)
+      |> Api.create!()
+
+      Comment
+      |> Ash.Changeset.new(%{title: "c"})
+      |> Ash.Changeset.manage_relationship(:post, post1, type: :append_and_remove)
+      |> Api.create!()
+
+      post2 =
+        Post
+        |> Ash.Changeset.new(%{title: "title"})
+        |> Api.create!()
+
+      Comment
+      |> Ash.Changeset.new(%{title: "a"})
+      |> Ash.Changeset.manage_relationship(:post, post2, type: :append_and_remove)
+      |> Api.create!()
+
+      Comment
+      |> Ash.Changeset.new(%{title: "b"})
+      |> Ash.Changeset.manage_relationship(:post, post2, type: :append_and_remove)
+      |> Api.create!()
+
+      post3 =
+        Post
+        |> Ash.Changeset.new(%{title: "title"})
+        |> Api.create!()
+
+      Comment
+      |> Ash.Changeset.new(%{title: "c"})
+      |> Ash.Changeset.manage_relationship(:post, post3, type: :append_and_remove)
+      |> Api.create!()
+
+      Comment
+      |> Ash.Changeset.new(%{title: "d"})
+      |> Ash.Changeset.manage_relationship(:post, post3, type: :append_and_remove)
+      |> Api.create!()
+
+      assert [%{last_comment: "d"}, %{last_comment: "c"}] =
+               Post
+               |> Ash.Query.load(:last_comment)
+               |> Ash.Query.sort(last_comment: :desc)
+               |> Ash.Query.limit(2)
+               |> Api.read!()
+    end
   end
 
   test "sum aggregates show the same value with filters on the sum vs filters on relationships" do

test/support/resources/post.ex

@@ -179,6 +179,10 @@ defmodule AshPostgres.Test.Post do
       sort(title: :asc_nils_last)
     end
 
+    first :last_comment, :comments, :title do
+      sort(title: :desc)
+    end
+
     max(:highest_comment_rating, [:comments, :ratings], :score)
     min(:lowest_comment_rating, [:comments, :ratings], :score)
     avg(:avg_comment_rating, [:comments, :ratings], :score)