test: update_all transaction

test/update_all_test.exs

@@ -0,0 +1,133 @@
+# SPDX-FileCopyrightText: 2019 ash_postgres contributors <https://github.com/ash-project/ash_postgres/graphs/contributors>
+#
+# SPDX-License-Identifier: MIT
+
+defmodule AshPostgres.UpdateAllTest do
+  @moduledoc """
+  Verifies `Ash.update_all/3` (record-by-record bulk update) against a real transactional data
+  layer, focusing on what ETS cannot show: with `transaction: :per_record` a single record failing
+  *at write time* (a check-constraint violation) rolls back only that record while its siblings
+  commit, whereas the default `transaction: :batch` rolls the whole batch back.
+
+  `AshPostgres.Test.Post` has `check_constraint(:price, "price_must_be_positive", check: "price > 0")`,
+  so a negative `price` produces a genuine Postgres write-time error mid-batch.
+  """
+  use AshPostgres.RepoCase, async: false
+
+  alias AshPostgres.Test.Post
+
+  require Ash.Query
+
+  defp create_post(title, price) do
+    Post
+    |> Ash.Changeset.for_create(:create, %{title: title, price: price})
+    |> Ash.create!()
+  end
+
+  defp reload(post), do: Ash.get!(Post, post.id)
+
+  # Error classes wrap the concrete error; dig out the first one of the given type.
+  defp find_error(%struct{} = error, struct), do: error
+
+  defp find_error(%{errors: errors}, struct) when is_list(errors) do
+    Enum.find_value(errors, &find_error(&1, struct))
+  end
+
+  defp find_error(_error, _struct), do: nil
+
+  describe "transaction: :per_record" do
+    test "a write-time failure rolls back only the failing record; siblings commit (contrast: :batch rolls back everything)" do
+      # Same mid-batch failure (the second record violates check_constraint price > 0)
+      # run two ways: once per-record, once as a single batch. Each gets its own posts
+      # so the two runs can't interfere; the contrast is asserted at the end.
+      pr1 = create_post("one", 10)
+      pr2 = create_post("two", 10)
+      pr3 = create_post("three", 10)
+
+      b1 = create_post("one", 10)
+      b2 = create_post("two", 10)
+      b3 = create_post("three", 10)
+
+      per_record_result =
+        Ash.update_all(
+          [
+            {pr1, %{price: 1}},
+            {pr2, %{price: -5}},
+            {pr3, %{price: 3}}
+          ],
+          :update,
+          resource: Post,
+          transaction: :per_record,
+          stop_on_error?: false,
+          return_records?: true,
+          return_errors?: true,
+          sorted?: true
+        )
+
+      batch_result =
+        Ash.update_all(
+          [
+            {b1, %{price: 1}},
+            {b2, %{price: -5}},
+            {b3, %{price: 3}}
+          ],
+          :update,
+          resource: Post,
+          transaction: :batch,
+          stop_on_error?: false,
+          return_records?: true,
+          return_errors?: true
+        )
+
+      assert %Ash.BulkResult{
+               status: :partial_success,
+               error_count: 1,
+               records: records,
+               errors: [error]
+             } = per_record_result
+
+      assert Enum.map(records, & &1.price) == [1, 3]
+      assert Enum.map(records, & &1.__metadata__.bulk_update_index) == [0, 2]
+
+      invalid = find_error(error, Ash.Error.Changes.InvalidAttribute)
+      assert invalid.field == :price
+      assert invalid.message =~ "bad price"
+      assert [1 | _] = error.path
+
+      assert %Ash.BulkResult{status: batch_status} = batch_result
+      assert batch_status in [:error, :partial_success]
+
+      # The crucial contrast ETS could not make. With :per_record the failing record is
+      # rolled back to its own savepoint while its siblings commit; with :batch every
+      # record shares one transaction, so the good writes roll back along with the bad.
+      assert reload(pr1).price == 1
+      assert reload(pr3).price == 3
+      assert reload(pr2).price == 10
+
+      assert reload(b1).price == 10
+      assert reload(b2).price == 10
+      assert reload(b3).price == 10
+    end
+
+    test "every record commits when none fail" do
+      p1 = create_post("a", 10)
+      p2 = create_post("b", 10)
+
+      result =
+        Ash.update_all(
+          [{p1, %{price: 4}}, {p2, %{price: 7}}],
+          :update,
+          resource: Post,
+          transaction: :per_record,
+          return_records?: true,
+          sorted?: true
+        )
+
+      assert %Ash.BulkResult{status: :success, records: [r1, r2]} = result
+      assert r1.price == 4
+      assert r2.price == 7
+      assert reload(p1).price == 4
+      assert reload(p2).price == 7
+    end
+  end
+end