improvement: support prefer_transaction?

lib/data_layer.ex

@@ -605,6 +605,11 @@ defmodule AshPostgres.DataLayer do
 
   import Ecto.Query, only: [from: 2, subquery: 1]
 
+  @impl true
+  def prefer_transaction?(resource) do
+    AshPostgres.DataLayer.Info.repo(resource, :mutate).prefer_transaction?()
+  end
+
   @impl true
   def can?(_, :async_engine), do: true
   def can?(_, :bulk_create), do: true
@@ -1773,7 +1778,12 @@ defmodule AshPostgres.DataLayer do
             |> AshSql.Bindings.default_bindings(resource, AshPostgres.SqlImplementation)
 
           upsert_set =
-            upsert_set(resource, changesets, options)
+            upsert_set(
+              resource,
+              changesets,
+              options[:upsert_keys] || Ash.Resource.Info.primary_key(resource),
+              options
+            )
 
           on_conflict =
             case AshSql.Atomics.query_with_atomics(
@@ -1785,7 +1795,11 @@ defmodule AshPostgres.DataLayer do
                    upsert_set
                  ) do
               :empty ->
-                {:replace, options[:upsert_keys] || Ash.Resource.Info.primary_key(resource)}
+                if options[:return_records?] do
+                  {:replace, options[:upsert_keys] || Ash.Resource.Info.primary_key(resource)}
+                else
+                  :nothing
+                end
 
               {:ok, query} ->
                 query
@@ -1913,7 +1927,7 @@ defmodule AshPostgres.DataLayer do
     fun.()
   end
 
-  defp upsert_set(resource, changesets, options) do
+  defp upsert_set(resource, changesets, keys, options) do
     attributes_changing_anywhere =
       changesets |> Enum.flat_map(&Map.keys(&1.attributes)) |> Enum.uniq()
 
@@ -1926,7 +1940,7 @@ defmodule AshPostgres.DataLayer do
 
     fields_to_upsert =
       upsert_fields --
-        Keyword.keys(Enum.at(changesets, 0).atomics)
+        Keyword.keys(Enum.at(changesets, 0).atomics) -- keys
 
     fields_to_upsert
     |> Enum.uniq()

lib/repo.ex

@@ -69,6 +69,9 @@ defmodule AshPostgres.Repo do
   @doc "The default prefix(postgres schema) to use when building queries"
   @callback default_prefix() :: String.t()
 
+  @doc "Whether or not to explicitly start and close a transaction for each action, even if there are no transaction hooks"
+  @callback prefer_transaction?() :: boolean
+
   @doc "Allows overriding a given migration type for *all* fields, for example if you wanted to always use :timestamptz for :utc_datetime fields"
   @callback override_migration_type(atom) :: atom
   @doc "Should the repo should be created by `mix ash_postgres.create`?"
@@ -102,6 +105,9 @@ defmodule AshPostgres.Repo do
       def create?, do: true
       def drop?, do: true
 
+      # default to false in 4.0
+      def prefer_transaction?, do: true
+
       def transaction!(fun) do
         case fun.() do
           {:ok, value} -> value
@@ -242,6 +248,7 @@ defmodule AshPostgres.Repo do
                      on_transaction_begin: 1,
                      installed_extensions: 0,
                      all_tenants: 0,
+                     prefer_transaction?: 0,
                      tenant_migrations_path: 0,
                      default_prefix: 0,
                      override_migration_type: 1,

test/cve/empty_atomic_non_bulk_actions_policy_bypass_test.exs

@@ -16,8 +16,6 @@ defmodule AshPostgres.EmptyAtomicNonBulkActionsPolicyBypassTest do
       |> Ash.Changeset.for_create(:create, %{})
       |> Ash.create!()
 
-    Logger.configure(level: :debug)
-
     assert_raise Ash.Error.Forbidden, fn ->
       post
       |> Ash.Changeset.for_update(:empty_update, %{}, authorize?: true)

test/support/test_repo.ex

@@ -7,6 +7,8 @@ defmodule AshPostgres.TestRepo do
     send(self(), data)
   end
 
+  def prefer_transaction?, do: false
+
   def installed_extensions do
     ["ash-functions", "uuid-ossp", "pg_trgm", "citext", AshPostgres.TestCustomExtension, "ltree"] --
       Application.get_env(:ash_postgres, :no_extensions, [])

test/test_helper.exs

@@ -1,4 +1,4 @@
-ExUnit.start(capture_log: true)
+ExUnit.start(capture_log: false)
 
 exclude_tags =
   case System.get_env("PG_VERSION") do