Return 404 if account to filter notifications from is not found

lib/pleroma/web/mastodon_api/controllers/notification_controller.ex

@@ -23,6 +23,23 @@ defmodule Pleroma.Web.MastodonAPI.NotificationController do
   plug(Pleroma.Plugs.EnsurePublicOrAuthenticatedPlug)
 
   # GET /api/v1/notifications
+  def index(conn, %{"account_id" => account_id} = params) do
+    case Pleroma.User.get_cached_by_id(account_id) do
+      %{ap_id: account_ap_id} ->
+        params =
+          params
+          |> Map.delete("account_id")
+          |> Map.put("account_ap_id", account_ap_id)
+
+        index(conn, params)
+
+      _ ->
+        conn
+        |> put_status(:not_found)
+        |> json(%{"error" => "Account is not found"})
+    end
+  end
+
   def index(%{assigns: %{user: user}} = conn, params) do
     notifications = MastodonAPI.get_notifications(user, params)
 

lib/pleroma/web/mastodon_api/mastodon_api.ex

@@ -56,7 +56,7 @@ def get_notifications(user, params \\ %{}) do
     user
     |> Notification.for_user_query(options)
     |> restrict(:exclude_types, options)
-    |> restrict(:account_id, options)
+    |> restrict(:account_ap_id, options)
     |> Pagination.fetch_paginated(params)
   end
 
@@ -73,7 +73,7 @@ defp cast_params(params) do
       reblogs: :boolean,
       with_muted: :boolean,
       with_move: :boolean,
-      account_id: :string
+      account_ap_id: :string
     }
 
     changeset = cast({%{}, param_types}, params, Map.keys(param_types))
@@ -90,11 +90,8 @@ defp restrict(query, :exclude_types, %{exclude_types: mastodon_types = [_ | _]})
     |> where([q, a], not fragment("? @> ARRAY[?->>'type']::varchar[]", ^ap_types, a.data))
   end
 
-  defp restrict(query, :account_id, %{account_id: account_id}) do
+  defp restrict(query, :account_ap_id, %{account_ap_id: account_ap_id}) do
-    case User.get_cached_by_id(account_id) do
+    where(query, [n, a], a.actor == ^account_ap_id)
-      %{ap_id: ap_id} -> where(query, [n, a], a.actor == ^ap_id)
-      _ -> where(query, [n, a], a.actor == "fake ap id")
-    end
   end
 
   defp restrict(query, _, _), do: query

test/web/mastodon_api/controllers/notification_controller_test.exs

@@ -478,11 +478,11 @@ test "account_id", %{conn: conn} do
                |> get("/api/v1/notifications", %{account_id: account_id})
                |> json_response(200)
 
-      assert [] =
+      assert %{"error" => "Account is not found"} =
                conn
                |> assign(:user, user)
                |> get("/api/v1/notifications", %{account_id: "cofe"})
-               |> json_response(200)
+               |> json_response(404)
     end
   end