fix: properly turn custom index keys into atoms

improvement: support new transaction info with hooks

lib/custom_index.ex

@@ -59,6 +59,7 @@ defmodule AshPostgres.CustomIndex do
 
   # sobelow_skip ["DOS.StringToAtom"]
   def transform(%__MODULE__{fields: fields} = index) do
+    {:ok,
      %{
        index
        | fields:
@@ -69,7 +70,7 @@ defmodule AshPostgres.CustomIndex do
                String.to_atom(field)
              end
            end)
-    }
+     }}
   end
 
   def name(_resource, %{name: name}) when is_binary(name) do

lib/data_layer.ex

@@ -52,6 +52,7 @@ defmodule AshPostgres.DataLayer do
     ],
     target: AshPostgres.CustomIndex,
     schema: AshPostgres.CustomIndex.schema(),
+    transform: {AshPostgres.CustomIndex, :transform, []},
     args: [:fields]
   }
 
@@ -1633,7 +1634,12 @@ defmodule AshPostgres.DataLayer do
   end
 
   @impl true
-  def transaction(resource, func, timeout \\ nil) do
+  def transaction(resource, func, timeout \\ nil, reason \\ %{type: :custom, metadata: %{}}) do
+    func = fn ->
+      AshPostgres.DataLayer.Info.repo(resource).on_transaction_begin(reason)
+      func.()
+    end
+
     if timeout do
       AshPostgres.DataLayer.Info.repo(resource).transaction(func, timeout: timeout)
     else

lib/repo.ex

@@ -37,6 +37,8 @@ defmodule AshPostgres.Repo do
   """
   @callback min_pg_version() :: integer()
 
+  @callback on_transaction_begin(reason :: Ash.DataLayer.transaction_reason()) :: term
+
   @doc "Return a list of all schema names (only relevant for a multitenant implementation)"
   @callback all_tenants() :: [String.t()]
   @doc "The path where your tenant migrations are stored (only relevant for a multitenant implementation)"
@@ -87,7 +89,10 @@ defmodule AshPostgres.Repo do
         {:ok, new_config}
       end
 
+      def on_transaction_begin(_reason), do: :ok
+
       defoverridable init: 2,
+                     on_transaction_begin: 1,
                      installed_extensions: 0,
                      all_tenants: 0,
                      tenant_migrations_path: 0,