From 6ad57501ff97ad66813bcddd6136347425a446da Mon Sep 17 00:00:00 2001
From: Zach Daniel <zach@zachdaniel.dev>
Date: Sun, 25 Sep 2022 14:41:29 -0400
Subject: [PATCH] improvement: upgrade to new `exists` usage

---
 lib/expr.ex                 |  8 +++----
 mix.exs                     |  3 ++-
 test/filter_test.exs        | 48 +++++++++++++++++++++++++++++++++++++
 test/support/types/money.ex |  1 +
 4 files changed, 54 insertions(+), 6 deletions(-)

diff --git a/lib/expr.ex b/lib/expr.ex
index 149dffa..390f29b 100644
--- a/lib/expr.ex
+++ b/lib/expr.ex
@@ -732,12 +732,12 @@ defmodule AshPostgres.Expr do
 
   defp do_dynamic_expr(
          query,
-         %Exists{path: [first | rest], expr: expr},
+         %Exists{at_path: at_path, path: [first | rest], expr: expr},
          bindings,
          _embedded?,
          _type
        ) do
-    resource = query.__ash_bindings__.resource
+    resource = Ash.Resource.Info.related(query.__ash_bindings__.resource, at_path)
     first_relationship = Ash.Resource.Info.relationship(resource, first)
 
     filter = %Ash.Filter{expression: expr, resource: first_relationship.destination}
@@ -760,7 +760,7 @@ defmodule AshPostgres.Expr do
       ref_binding(
         %Ref{
           attribute: Ash.Resource.Info.attribute(resource, first_relationship.source_attribute),
-          relationship_path: [],
+          relationship_path: at_path,
           resource: resource
         },
         bindings
@@ -788,8 +788,6 @@ defmodule AshPostgres.Expr do
               field(through, ^first_relationship.source_attribute_on_join_resource),
           select: 1
         )
-
-        # )
       else
         Ecto.Query.from(destination in filtered,
           select: [1],
diff --git a/mix.exs b/mix.exs
index 763d1fa..52d3d05 100644
--- a/mix.exs
+++ b/mix.exs
@@ -138,7 +138,8 @@ defmodule AshPostgres.MixProject do
       {:ecto, "~> 3.8"},
       {:jason, "~> 1.0"},
       {:postgrex, ">= 0.0.0"},
-      {:ash, ash_version("~> 2.0.0-rc.9")},
+      {:ash,
+       ash_version(github: "ash-project/ash", ref: "3b803d4c552f0df3f8d07a8da9bb1bdd4dfc8fc6")},
       {:git_ops, "~> 2.4.5", only: :dev},
       {:ex_doc, "~> 0.22", only: :dev, runtime: false},
       {:ex_check, "~> 0.14", only: :dev},
diff --git a/test/filter_test.exs b/test/filter_test.exs
index 65caac9..6de1bbb 100644
--- a/test/filter_test.exs
+++ b/test/filter_test.exs
@@ -622,6 +622,54 @@ defmodule AshPostgres.FilterTest do
                |> Api.read!()
     end
 
+    test "it works with an `at_path`" do
+      post =
+        Post
+        |> Ash.Changeset.new(%{title: "a"})
+        |> Api.create!()
+
+      other_post =
+        Post
+        |> Ash.Changeset.new(%{title: "other_a"})
+        |> Api.create!()
+
+      Comment
+      |> Ash.Changeset.new(%{title: "comment"})
+      |> Ash.Changeset.manage_relationship(:post, post, type: :append_and_remove)
+      |> Api.create!()
+
+      Comment
+      |> Ash.Changeset.new(%{title: "comment"})
+      |> Ash.Changeset.manage_relationship(:post, other_post, type: :append_and_remove)
+      |> Api.create!()
+
+      Post
+      |> Ash.Changeset.new(%{title: "b"})
+      |> Ash.Changeset.manage_relationship(:linked_posts, [post], type: :append_and_remove)
+      |> Api.create!()
+
+      Post
+      |> Ash.Changeset.new(%{title: "b"})
+      |> Ash.Changeset.manage_relationship(:linked_posts, [other_post], type: :append_and_remove)
+      |> Api.create!()
+
+      assert [%{title: "b"}] =
+               Post
+               |> Ash.Query.filter(
+                 linked_posts.title == "a" and
+                   linked_posts.exists(comments, title == ^"comment")
+               )
+               |> Api.read!()
+
+      assert [%{title: "b"}] =
+               Post
+               |> Ash.Query.filter(
+                 linked_posts.title == "a" and
+                   linked_posts.exists(comments, title == ^"comment")
+               )
+               |> Api.read!()
+    end
+
     test "it works with nested relationships inside of exists" do
       post =
         Post
diff --git a/test/support/types/money.ex b/test/support/types/money.ex
index 2c829e3..fde16df 100644
--- a/test/support/types/money.ex
+++ b/test/support/types/money.ex
@@ -1,4 +1,5 @@
 defmodule AshPostgres.Test.Money do
+  @moduledoc false
   use Ash.Resource,
     data_layer: :embedded