fix: add catch-all can?/3 clause for custom item actions

lib/ash_backpex/live_resource/transformers/generate_backpex.ex

@@ -408,6 +408,25 @@ defmodule AshBackpex.LiveResource.Transformers.GenerateBackpex do
           def can?(_assigns, :delete, _item), do: false
         end
 
+        # Fallback for custom item actions and any other actions
+        # Checks Ash authorization if a matching action exists, otherwise allows by default
+        def can?(assigns, action, item) do
+          case Ash.Resource.Info.action(@resource, action) do
+            nil ->
+              true
+
+            ash_action ->
+              target =
+                if is_struct(item) and item.__struct__ == @resource do
+                  {item, ash_action.name}
+                else
+                  {@resource, ash_action.name}
+                end
+
+              Ash.can?(target, Map.get(assigns, :current_user))
+          end
+        end
+
         def maybe_default_options(assigns) do
           case assigns do
             %{field: {attribute_name, _field_cfg}} ->

test/ash_backpex/authz_test.exs

@@ -41,6 +41,20 @@ defmodule AshBackpex.AuthzTest do
     end
   end
 
+  describe "AshBackpex.LiveResource :: can? with custom item actions" do
+    test "returns true for unknown actions that don't exist on the resource" do
+      # :promote is not an Ash action on Item, so fallback returns true
+      assert TestCustomItemActionLive.can?(%{current_user: nil}, :promote, %{})
+      assert TestCustomItemActionLive.can?(%{current_user: nil}, :some_unknown_action, %{})
+    end
+
+    test "checks Ash authorization when action exists on resource" do
+      # :read exists on Item resource, so it checks Ash.can?
+      # Item has no policies, so it should return true
+      assert TestCustomItemActionLive.can?(%{current_user: nil}, :read, %{})
+    end
+  end
+
   describe "AshBackpex.Adapter :: it can" do
     test "list/3" do
       user = user()

test/support/test_live.ex

@@ -113,3 +113,46 @@ defmodule TestLayout do
     """
   end
 end
+
+# Custom item action for testing can?/3 fallback
+defmodule TestPromoteItemAction do
+  @moduledoc false
+  use BackpexWeb, :item_action
+
+  @impl Backpex.ItemAction
+  def icon(assigns, _item) do
+    ~H"""
+    <Backpex.HTML.CoreComponents.icon
+      name="hero-arrow-up-circle"
+      class="h-5 w-5 cursor-pointer transition duration-75 hover:scale-110 hover:text-success"
+    />
+    """
+  end
+
+  @impl Backpex.ItemAction
+  def label(_assigns, _item), do: "Promote"
+
+  @impl Backpex.ItemAction
+  def handle(socket, _items, _data) do
+    {:ok, socket}
+  end
+end
+
+# LiveResource with custom item action for testing can?/3 fallback
+defmodule TestCustomItemActionLive do
+  @moduledoc false
+  use AshBackpex.LiveResource
+
+  backpex do
+    resource(AshBackpex.TestDomain.Item)
+    layout({TestLayout, :admin})
+
+    item_actions do
+      action :promote, TestPromoteItemAction
+    end
+
+    fields do
+      field(:name)
+    end
+  end
+end