hey Glad to see that you are eager to fix this. However, your change is immediately breaking (especially for ConversationHandler), because you pass an unexpected argument to the done_callbacks.

but for now this fix is the only way for letting users of the library retry on timeouts, other network exceptions or flood limit exceptions from telegram's API

You can also just add proper error handling directly in your pooled_function. Promise is used two places:

• MessageQueue - deprecated anyway, so no use to add new features
• run_async, including ConversationHandler - here callbacks get error handling via dispatchers error handlers

Moreover, done_callback is only used in ConversationHandler and we don't need additional error handling there.

If you want to, you are very welcome to update your PR to the approach detailed in #2542 (comment) :)

superseded by #2544. Nevertheless, thanks for taking the time to PR :)