[callback] treat missing message context as no reply_to_message in template quick-reply

[WouterDurnez]

The bug

WhatsApp Cloud API does not always include the context field on incoming type: "button" messages (template quick-reply presses). We hit this in production (EU WABA, 2026-07-13) with a payload that carried the newer user_id / from_user_id fields but no context:

{
  "from": "32400000001",
  "from_user_id": "BE.0000000000000000",
  "id": "wamid.HBg...",
  "timestamp": "1783932397",
  "type": "button",
  "button": {"payload": "...", "text": "..."}
}

CallbackButton.from_update (and CallbackSelection.from_update) index msg["context"] unconditionally:

File "pywa_async/server.py", line 231, in _call_handlers
    ].from_update(client=self, update=raw_update)
File "pywa/types/callback.py", line 298, in from_update
    reply_to_message=ReplyToMessage.from_dict(msg["context"]),
KeyError: 'context'

The server catches this, logs Failed to construct update, and still returns 200 — so Meta never redelivers and the user's button press is silently lost (the registered handler never fires).

The fix

Parse context the same way Message.from_update already does (message.py: content.get("context", {}) → ReplyToMessage.from_dict(context) if context.get("id") else None): treat it as optional and set reply_to_message=None when absent. Annotations and docstrings updated to ReplyToMessage | None accordingly (matching Message.reply_to_message).

Tests

Added quick_reply_without_context / callback_without_context update fixtures plus reply_to_message assertions in test_updates.py. Without the fix, the new fixtures reproduce the production crash immediately (fixture construction in tests/common.py raises KeyError: 'context'); with it, the full suite passes with no regressions.

Thanks for the great library! 🙏

[david-lev]

Hi @WouterDurnez, thanks for the contribution and for adding the test cases!

Just to help me understand the root cause better, could you share which version of the messages webhook field you are currently using where you ran into this?

You can find this information in your app settings > WhatsApp > Configuration:

Also, did you notice if there's a specific scenario that triggers CallbackSelection to drop the context field as well?

Thanks again!

[WouterDurnez]

Hi David, the messages webhook field is using v25.0.

The observed case was a template quick-reply button (type: "button"). We’ve only seen one occurrence and haven’t observed CallbackSelection/list_reply dropping context.

I included CallbackSelection defensively because its constructor makes the same unconditional msg["context"] assumption; that test is synthetic rather than based on a production payload. Happy to narrow the change if you prefer.

Thanks!

[david-lev]

Thanks for the clarification! That makes total sense.

The reason this only happens for CallbackButton is because it handles two distinct payload types: interactive (for regular button_reply presses) and button (for template QuickReplyButton clicks). Meta omits the context field specifically on that button template type.

pywa/pywa/types/callback.py

Lines 280 to 288 in 6ebd161

	match msg_type := msg["type"]:
	case MessageType.INTERACTIVE:
	title = msg["interactive"]["button_reply"]["title"]
	data = msg["interactive"]["button_reply"]["id"]
	case MessageType.BUTTON:
	title = msg["button"]["text"]
	data = msg["button"]["payload"]
	case _:
	raise ValueError(f"Invalid message type {msg_type}")

Since CallbackSelection only ever handles interactive payloads (list_reply), it shouldn't actually be at risk of dropping the context field.

Let's go ahead and narrow the change down. Could you please:

• Revert the defensive changes and synthetic tests made to CallbackSelection.
• Update the docstrings for reply_to_message in CallbackButton (for both the synchronous and asynchronous files) to explicitly mention that it can be None specifically when a template quick-reply button is clicked.

Appreciate the thoroughness! Let me know when you've updated it.

[WouterDurnez]

Done in fbaadb6 👍

• Reverted all CallbackSelection changes (defensive context parsing, | None annotation, docstring, and the synthetic callback_without_context fixture/assertions) — it's back to exactly what's on master.
• Updated the reply_to_message docstring on CallbackButton in both pywa/types/callback.py and pywa_async/types/callback.py to state it's None specifically when a template QuickReplyButton is clicked (WhatsApp omits context on button payloads).

Full suite passes (158 passed). Thanks for the review!

[david-lev]

Awesome, thank you for the quick update and for cleaning that up! Everything looks perfectly dialed in now.
Merging this right away. Thanks again for your contribution!