dispatcher.utter_message(template=...) no longer works in a custom action

[yennycheung]

Rasa version: 2.4.0

Rasa SDK version (if used & relevant): 2.4.0

Rasa X version (if used & relevant):

Python version:

Operating system (windows, osx, ...):

Issue:
dispatcher.utter_message(template=...) no longer works in a custom action. Nothing is uttered by the bot. This is related to the changes introduced in #6964.

Error (including full traceback):
The debug logs between Rasa 2.2 & 2.4 look the same, up to this point, after the custom action executed:

# rasa 2.2
2021-03-15 16:01:13 DEBUG    rasa.core.processor  - Action 'action_show_balance' ended with events '[BotUttered('Your bank account balance is $49691.97.', {"elements": null, "quick_replies": null, "buttons": null, "attachment": null, "image": null, "custom": null}, {"template_name": "utter_account_balance", "init_account_balance": "49691.97"}, 1615838473.6100328)]'.
# rasa 2.4
2021-03-15 15:54:31 DEBUG    rasa.core.processor  - Action 'action_show_balance' ended with events '[BotUttered('None', {"elements": null, "quick_replies": null, "buttons": null, "attachment": null, "image": null, "custom": null}, {"template": "utter_account_balance", "init_account_balance": "52946.23"}, 1615838071.5593858)]'.

Command or request that led to error:

Content of configuration file (config.yml) (if relevant):

Content of domain file (domain.yml) (if relevant):

[yennycheung]

Reported by @ArjaanBuijk and by this forum post: https://forum.rasa.com/t/dispatcher-utter-message-template-not-passing-text-attribute-to-slack-postmessage-in-rasa-2-4-0/41224

[yennycheung]

I'm trying to set up form bot to test the changes.

[yennycheung]

@wochinge my question on the SDK. How are people using it now? Do they fork it and customize it? If so, I think we can include both fields and comment that if they use the older OSS version, they should use template?

[wochinge]

my question on the SDK. How are people using it now? Do they fork it and customize it? If so, I think we can include both fields and comment that if they use the older OSS version, they should use template?

They either use our rasa-sdk or they write their own in their own language (as I e.g. did here. Forking and customizing the Python one over a long time period is not a thing. I mean they should ideally do the same as we will do in our Python SDK and send both the template and response key for a while to be compatible with older and newer Rasa Open Source versions. Does that make sense?

[yennycheung]

They either use our rasa-sdk or they write their own in their own language (as I e.g. did here. Forking and customizing the Python one over a long time period is not a thing. I mean they should ideally do the same as we will do in our Python SDK and send both the template and response key for a while to be compatible with older and newer Rasa Open Source versions. Does that make sense?

It does. Got it. How do I manually test the sdk?

[wochinge]

See here. You run rasa using rasa run and with the action server specified in endpoints.yml. You run the action server via rasa run actions

[JEM-Mosig]

Got the same issue on WSL Ubuntu, but it looks like a solution is on track :)