updading set_empty_attributes and forward_attributes as well

lib/phx_component_helpers.ex

@@ -250,7 +250,7 @@ defmodule PhxComponentHelpers do
     for option <- opts, reduce: %{} do
       acc ->
         assigns = handle_forward_option(assigns, option)
-        Map.merge(acc, assigns)
+        assign(assigns, acc)
     end
   end
 

lib/phx_component_helpers/set_attributes.ex

@@ -40,7 +40,7 @@ defmodule PhxComponentHelpers.SetAttributes do
     for attr <- attributes, reduce: assigns do
       acc ->
         heex_attr_key = heex_attribute_key(attr)
-        Map.put_new(acc, heex_attr_key, [])
+        assign_new(acc, heex_attr_key, fn -> [] end)
     end
   end
 
@@ -50,6 +50,16 @@ defmodule PhxComponentHelpers.SetAttributes do
 
   def assign(assigns, key, value), do: Map.put(assigns, key, value)
 
+  def assign(%{__changed__: _changes} = assigns, keyword_or_map),
+    do: Phoenix.LiveView.assign(assigns, keyword_or_map)
+
+  def assign(assigns, keyword_or_map), do: Map.merge(assigns, keyword_or_map)
+
+  def assign_new(%{__changed__: _changes} = assigns, key, fun),
+    do: Phoenix.LiveView.assign_new(assigns, key, fun)
+
+  def assign_new(assigns, key, fun), do: Map.put_new_lazy(assigns, key, fun)
+
   defp heex_escaped(val, opts) do
     if opts[:json] do
       @json_library.encode!(val)