fix(whatsapp): treat a reply to the bot as addressing it (#1217)

Co-authored-by: Claude Opus 5 <noreply@anthropic.com>

Author: vikng-dev

crates/whatsapp/src/handlers.rs

@@ -834,12 +834,21 @@ fn context_info_mentions_owner(
     own_lid: Option<&Jid>,
 ) -> bool {
     context.is_some_and(|context| {
-        context.mentioned_jid.iter().any(|mentioned| {
+        let mentioned = context.mentioned_jid.iter().any(|mentioned| {
             mentioned
                 .parse::<Jid>()
                 .ok()
                 .is_some_and(|jid| is_owner_user(&jid, own_pn, own_lid))
-        })
+        });
+        // A reply is the other way to address someone in a group. It sets
+        // `participant` to the quoted message's author and leaves
+        // `mentioned_jid` empty, so checking mentions alone drops every reply.
+        let replied_to = context
+            .participant
+            .as_deref()
+            .and_then(|participant| participant.parse::<Jid>().ok())
+            .is_some_and(|jid| is_owner_user(&jid, own_pn, own_lid));
+        mentioned || replied_to
     })
 }
 
@@ -1168,6 +1177,40 @@ async fn handle_otp_flow(
 mod tests {
     use {super::*, wacore::types::message::MessageSource};
 
+    fn reply_context(participant: &str) -> wa::ContextInfo {
+        wa::ContextInfo {
+            participant: Some(participant.to_owned()),
+            ..Default::default()
+        }
+    }
+
+    #[test]
+    fn reply_to_the_bot_counts_as_a_mention() {
+        let own_pn: Jid = "15551234567@s.whatsapp.net".parse().unwrap();
+        let ctx = reply_context("15551234567@s.whatsapp.net");
+
+        assert!(ctx.mentioned_jid.is_empty(), "a reply carries no mention");
+        assert!(context_info_mentions_owner(Some(&ctx), Some(&own_pn), None));
+    }
+
+    #[test]
+    fn reply_to_anyone_else_does_not() {
+        let own_pn: Jid = "15551234567@s.whatsapp.net".parse().unwrap();
+        let own_lid: Jid = "259557842534599@lid".parse().unwrap();
+
+        for ctx in [
+            reply_context("11111111111@s.whatsapp.net"),
+            reply_context("not a jid"),
+            wa::ContextInfo::default(),
+        ] {
+            assert!(!context_info_mentions_owner(
+                Some(&ctx),
+                Some(&own_pn),
+                Some(&own_lid)
+            ));
+        }
+    }
+
     #[test]
     fn owner_self_chat_detected_without_is_from_me_when_sender_and_chat_are_owner() {
         let own_lid: Jid = "259557842534599@lid".parse().unwrap();

docs/src/whatsapp.md

@@ -209,7 +209,7 @@ WhatsApp uses the same access control model as Telegram channels.
 | Mode | Behavior |
 |------|----------|
 | `always` | Bot may respond to allowed group messages without an @mention |
-| `mention` | Bot only responds in allowed groups when the account is @mentioned |
+| `mention` | Bot only responds in allowed groups when the account is @mentioned, or when someone replies to one of its messages |
 | `none` | Bot never responds in groups |
 
 ### OTP Self-Approval