ZMQStream2Pusher: Clear handling of images written if no notification socket

image_pusher/ZMQStream2Pusher.cpp

@@ -98,6 +98,7 @@ std::string ZMQStream2Pusher::Finalize() {
     if (transmission_error)
         ret += "Timeout sending images (e.g., writer disabled during data collection);";
     uint64_t images = 0;
+    bool images_saved = false;
     if (writer_notification_socket) {
         for (int i = 0; i < socket.size(); i++) {
             auto n = writer_notification_socket->Receive(run_number, run_name);
@@ -109,13 +110,17 @@ std::string ZMQStream2Pusher::Finalize() {
                 if (!n->ok)
                     ret += "Writer " + std::to_string(i) + ": " + n->error;
                 images += n->processed_images;
+                images_saved = true;
             }
         }
     }
 
     {
         std::unique_lock ul(images_written_mutex);
-        images_written = images;
+        if (images_saved)
+            images_written = images;
+        else
+            images_written = std::nullopt;
     }
     return ret;
 }