Add partial identity join sorting test

priv/test_repo/migrations/20260610180000_add_notification_recipients.exs

@@ -0,0 +1,75 @@
+# SPDX-FileCopyrightText: 2019 ash_postgres contributors <https://github.com/ash-project/ash_postgres/graphs/contributors>
+#
+# SPDX-License-Identifier: MIT
+
+defmodule AshPostgres.TestRepo.Migrations.AddNotificationRecipients do
+  use Ecto.Migration
+
+  def up do
+    create table(:notification_recipients, primary_key: false) do
+      add(:id, :uuid, null: false, default: fragment("gen_random_uuid()"), primary_key: true)
+      add(:order, :bigint)
+
+      add(
+        :post_id,
+        references(:posts,
+          column: :id,
+          name: "notification_recipients_post_id_fkey",
+          type: :uuid,
+          prefix: "public"
+        )
+      )
+
+      add(
+        :comment_id,
+        references(:comments,
+          column: :id,
+          name: "notification_recipients_comment_id_fkey",
+          type: :uuid,
+          prefix: "public"
+        )
+      )
+
+      add(
+        :user_id,
+        references(:users,
+          column: :id,
+          name: "notification_recipients_user_id_fkey",
+          type: :uuid,
+          prefix: "public"
+        )
+      )
+
+      add(
+        :staff_group_id,
+        references(:staff_group,
+          column: :id,
+          name: "notification_recipients_staff_group_id_fkey",
+          type: :uuid,
+          prefix: "public"
+        )
+      )
+    end
+
+    create(
+      unique_index(:notification_recipients, ["post_id", "user_id"],
+        name: "notification_recipients_post_user_index",
+        where: "(post_id IS NOT NULL) AND (user_id IS NOT NULL)"
+      )
+    )
+  end
+
+  def down do
+    drop_if_exists(
+      unique_index(:notification_recipients, ["post_id", "user_id"],
+        name: "notification_recipients_post_user_index"
+      )
+    )
+
+    drop(constraint(:notification_recipients, "notification_recipients_post_id_fkey"))
+    drop(constraint(:notification_recipients, "notification_recipients_comment_id_fkey"))
+    drop(constraint(:notification_recipients, "notification_recipients_user_id_fkey"))
+    drop(constraint(:notification_recipients, "notification_recipients_staff_group_id_fkey"))
+    drop(table(:notification_recipients))
+  end
+end

test/load_test.exs

@@ -8,6 +8,7 @@ defmodule AshPostgres.Test.LoadTest do
   alias AshPostgres.Test.{
     Author,
     Comment,
+    NotificationRecipient,
     Post,
     PostFollower,
     Record,
@@ -234,6 +235,40 @@ defmodule AshPostgres.Test.LoadTest do
     assert length(post.first_3_followers) == 2
   end
 
+  test "many_to_many can sort on a polymorphic partial identity join relationship" do
+    post =
+      Post
+      |> Ash.Changeset.for_create(:create, %{title: "a"})
+      |> Ash.create!()
+
+    followers =
+      for i <- 0..2 do
+        User
+        |> Ash.Changeset.for_create(:create, %{name: "user#{i}", is_active: true})
+        |> Ash.create!()
+      end
+
+    followers
+    |> Enum.zip([2, 0, 1])
+    |> Enum.each(fn {follower, order} ->
+      NotificationRecipient
+      |> Ash.Changeset.for_create(:create, %{
+        order: order,
+        post_id: post.id,
+        user_id: follower.id
+      })
+      |> Ash.create!()
+    end)
+
+    [post] =
+      Post
+      |> Ash.Query.for_read(:read, %{})
+      |> Ash.Query.load(:sorted_notification_users)
+      |> Ash.read!()
+
+    assert Enum.map(post.sorted_notification_users, & &1.name) == ["user1", "user2", "user0"]
+  end
+
   test "many_to_many loads work when nested" do
     source_post =
       Post

test/support/domain.ex

@@ -39,6 +39,7 @@ defmodule AshPostgres.Test.Domain do
     resource(AshPostgres.Test.Permalink)
     resource(AshPostgres.Test.Record)
     resource(AshPostgres.Test.PostFollower)
+    resource(AshPostgres.Test.NotificationRecipient)
     resource(AshPostgres.Test.StatefulPostFollower)
     resource(AshPostgres.Test.PostWithEmptyUpdate)
     resource(AshPostgres.Test.DbPoint)

test/support/resources/notification_recipient.ex

@@ -0,0 +1,56 @@
+# SPDX-FileCopyrightText: 2019 ash_postgres contributors <https://github.com/ash-project/ash_postgres/graphs/contributors>
+#
+# SPDX-License-Identifier: MIT
+
+defmodule AshPostgres.Test.NotificationRecipient do
+  @moduledoc false
+  use Ash.Resource,
+    domain: AshPostgres.Test.Domain,
+    data_layer: AshPostgres.DataLayer
+
+  postgres do
+    table "notification_recipients"
+    repo AshPostgres.TestRepo
+
+    identity_wheres_to_sql(post_user: "(post_id IS NOT NULL) AND (user_id IS NOT NULL)")
+  end
+
+  identities do
+    identity(:post_user, [:post_id, :user_id],
+      where: expr(not is_nil(post_id) and not is_nil(user_id))
+    )
+  end
+
+  actions do
+    default_accept(:*)
+
+    defaults([:create, :read, :update, :destroy])
+  end
+
+  attributes do
+    uuid_primary_key(:id)
+    attribute(:order, :integer, public?: true)
+  end
+
+  relationships do
+    belongs_to :post, AshPostgres.Test.Post do
+      public?(true)
+      allow_nil?(true)
+    end
+
+    belongs_to :comment, AshPostgres.Test.Comment do
+      public?(true)
+      allow_nil?(true)
+    end
+
+    belongs_to :user, AshPostgres.Test.User do
+      public?(true)
+      allow_nil?(true)
+    end
+
+    belongs_to :staff_group, AshPostgres.Test.StaffGroup do
+      public?(true)
+      allow_nil?(true)
+    end
+  end
+end

test/support/resources/post.ex

@@ -884,6 +884,11 @@ defmodule AshPostgres.Test.Post do
 
     has_many(:post_followers, AshPostgres.Test.PostFollower)
 
+    has_many :user_notification_recipients, AshPostgres.Test.NotificationRecipient do
+      filter(expr(not is_nil(user_id)))
+      sort(order: :asc)
+    end
+
     # For testing join_relationship limit inheritance
     has_many :top_three_post_followers, AshPostgres.Test.PostFollower do
       sort(order: :asc)
@@ -918,6 +923,15 @@ defmodule AshPostgres.Test.Post do
       sort: [Ash.Sort.expr_sort(parent(post_followers.order), :integer)]
     )
 
+    many_to_many(:sorted_notification_users, AshPostgres.Test.User,
+      public?: true,
+      through: AshPostgres.Test.NotificationRecipient,
+      join_relationship: :user_notification_recipients,
+      source_attribute_on_join_resource: :post_id,
+      destination_attribute_on_join_resource: :user_id,
+      sort: [Ash.Sort.expr_sort(parent(user_notification_recipients.order), :integer)]
+    )
+
     many_to_many :tags, AshPostgres.Test.Tag do
       public?(true)
       through(AshPostgres.Test.PostTag)