From 6ff462169dfe0f3f808e1b8008ce2a2ef71053d1 Mon Sep 17 00:00:00 2001
From: Zach Daniel <zach@zachdaniel.dev>
Date: Wed, 9 Oct 2024 22:32:39 -0400
Subject: [PATCH] improvement: StaleRecordError on skipped upsert

---
 lib/ash.ex                       | 10 ++++++++++
 lib/ash/actions/create/bulk.ex   |  3 +++
 lib/ash/actions/create/create.ex | 15 +++++++++++++++
 test/actions/create_test.exs     | 28 ++++++++++++++++++++++++++++
 4 files changed, 56 insertions(+)

diff --git a/lib/ash.ex b/lib/ash.ex
index 76ff2f4e0..ce61b2345 100644
--- a/lib/ash.ex
+++ b/lib/ash.ex
@@ -284,6 +284,12 @@ defmodule Ash do
                           doc:
                             "If a conflict is found based on the primary key, the record is updated in the database (requires upsert support)"
                         ],
+                        return_skipped_upsert?: [
+                          type: :boolean,
+                          default: false,
+                          doc:
+                            "If `true`, and a record was *not* upserted because its filter prevented the upsert, the original record (which was *not* upserted) will be returned."
+                        ],
                         upsert_identity: [
                           type: :atom,
                           doc:
@@ -578,6 +584,10 @@ defmodule Ash do
                                doc:
                                  "If a conflict is found based on the primary key, the record is updated in the database (requires upsert support)"
                              ],
+                             return_skipped_upsert?: [
+                               type: :boolean,
+                               hide: true
+                             ],
                              upsert_identity: [
                                type: :atom,
                                doc:
diff --git a/lib/ash/actions/create/bulk.ex b/lib/ash/actions/create/bulk.ex
index dadb66db4..00975f0a3 100644
--- a/lib/ash/actions/create/bulk.ex
+++ b/lib/ash/actions/create/bulk.ex
@@ -1263,6 +1263,9 @@ defmodule Ash.Actions.Create.Bulk do
                     end
 
                   case result do
+                    {:ok, %{__metadata__: %{upsert_skipped: true}}} ->
+                      []
+
                     {:ok, result} ->
                       {:ok,
                        [
diff --git a/lib/ash/actions/create/create.ex b/lib/ash/actions/create/create.ex
index f7a4d81c4..cb34f2732 100644
--- a/lib/ash/actions/create/create.ex
+++ b/lib/ash/actions/create/create.ex
@@ -363,6 +363,21 @@ defmodule Ash.Actions.Create do
                                 opts[:upsert_identity] || changeset.action.upsert_identity
                               )
                           )
+                          |> case do
+                            {:ok, %{__metadata__: %{upsert_skipped: true}}} = result ->
+                              if opts[:return_skipped_upsert?] do
+                                result
+                              else
+                                {:error,
+                                 Ash.Error.Changes.StaleRecord.exception(
+                                   resource: changeset.resource,
+                                   filter: changeset.filter
+                                 )}
+                              end
+
+                            other ->
+                              other
+                          end
                           |> Helpers.rollback_if_in_transaction(
                             changeset.resource,
                             changeset
diff --git a/test/actions/create_test.exs b/test/actions/create_test.exs
index 4d8a90548..ab9dc8903 100644
--- a/test/actions/create_test.exs
+++ b/test/actions/create_test.exs
@@ -616,6 +616,7 @@ defmodule Ash.Test.Actions.CreateTest do
                })
                |> Ash.create!(
                  upsert?: true,
+                 return_skipped_upsert?: true,
                  upsert_identity: :unique_title,
                  upsert_fields: [:contents, :updated_at],
                  upsert_condition: expr(contents != upsert_conflict(:contents))
@@ -624,6 +625,33 @@ defmodule Ash.Test.Actions.CreateTest do
       assert Ash.Resource.get_metadata(post, :upsert_skipped)
     end
 
+    test "skips upsert when condition doesn't match, returning error unless asked for" do
+      Post
+      |> Ash.Changeset.new()
+      |> Ash.Changeset.change_attributes(%{
+        title: "foo",
+        contents: "bar",
+        tag: "before"
+      })
+      |> Ash.create!()
+
+      assert_raise Ash.Error.Invalid, ~r/Stale/, fn ->
+        Post
+        |> Ash.Changeset.new()
+        |> Ash.Changeset.change_attributes(%{
+          title: "foo",
+          contents: "bar",
+          tag: "after"
+        })
+        |> Ash.create!(
+          upsert?: true,
+          upsert_identity: :unique_title,
+          upsert_fields: [:contents, :updated_at],
+          upsert_condition: expr(contents != upsert_conflict(:contents))
+        )
+      end
+    end
+
     test "timestamps will match each other" do
       post =
         Post