refactor(web): extract format_ash_error to MvWeb.ErrorHelpers

Use shared ErrorHelpers in UserLive.Index for consistent Ash error formatting.

lib/mv_web/error_helpers.ex

@@ -0,0 +1,25 @@
+defmodule MvWeb.ErrorHelpers do
+  @moduledoc """
+  Shared helpers for formatting errors in the web layer.
+
+  Use `format_ash_error/1` for Ash errors so behaviour stays consistent
+  (e.g. handling Invalid errors whose entries may lack a `:message` field).
+  """
+
+  @doc """
+  Formats an Ash error for display to the user.
+
+  Handles `Ash.Error.Invalid` by joining error messages; entries without
+  a `:message` field are inspected to avoid FunctionClauseError.
+  Other errors are inspected.
+  """
+  @spec format_ash_error(Ash.Error.t() | term()) :: String.t()
+  def format_ash_error(%Ash.Error.Invalid{errors: errors}) when is_list(errors) do
+    Enum.map_join(errors, ", ", fn
+      %{message: message} when is_binary(message) -> message
+      other -> inspect(other)
+    end)
+  end
+
+  def format_ash_error(error), do: inspect(error)
+end

lib/mv_web/live/user_live/index.ex

@@ -26,6 +26,7 @@ defmodule MvWeb.UserLive.Index do
   import MvWeb.LiveHelpers, only: [current_actor: 1]
 
   require Ash.Query
+  import MvWeb.ErrorHelpers, only: [format_ash_error: 1]
 
   @impl true
   def mount(_params, _session, socket) do
@@ -71,7 +72,7 @@ defmodule MvWeb.UserLive.Index do
              )}
 
           {:error, error} ->
-            {:noreply, put_flash(socket, :error, format_error(error))}
+            {:noreply, put_flash(socket, :error, format_ash_error(error))}
         end
 
       {:error, %Ash.Error.Query.NotFound{}} ->
@@ -82,7 +83,7 @@ defmodule MvWeb.UserLive.Index do
          put_flash(socket, :error, gettext("You do not have permission to access this user"))}
 
       {:error, error} ->
-        {:noreply, put_flash(socket, :error, format_error(error))}
+        {:noreply, put_flash(socket, :error, format_ash_error(error))}
     end
   end
 
@@ -144,15 +145,4 @@ defmodule MvWeb.UserLive.Index do
   defp toggle_order(:desc), do: :asc
   defp sort_fun(:asc), do: &<=/2
   defp sort_fun(:desc), do: &>=/2
-
-  defp format_error(%Ash.Error.Invalid{errors: errors}) when is_list(errors) do
-    Enum.map_join(errors, ", ", fn
-      %{message: message} when is_binary(message) -> message
-      other -> inspect(other)
-    end)
-  end
-
-  defp format_error(error) do
-    inspect(error)
-  end
 end