feat: list a direct conversation's participants (#189)

A direct conversation has participants like any conversation, and listing them is part of the conversation surface, but group_members could only answer for groups: the roster accessor sat on the group-only trait, so the direct arm returned an unsupported-function error even though the membership lives in the conversation's inner group.

members moves to the Convo trait and DirectV1Convo delegates it to that inner group. add_member stays on the group-only trait, so the direct arm keeps rejecting it.

core/conversations/src/conversation.rs

@@ -35,6 +35,10 @@ pub(crate) trait Convo<S: ExternalServices>: Identified + Send {
     /// Advances any time-driven protocol work (de-mls consensus deadlines) and
     /// reports what it observed, mirroring [`Self::handle_frame`].
     fn wakeup(&mut self, service_ctx: &mut ServiceContext<S>) -> Result<ConvoOutcome, ChatError>;
+
+    /// Each current member's MLS leaf-credential content (hex-encoded), self
+    /// included.
+    fn members(&self) -> Result<Vec<Vec<u8>>, ChatError>;
 }
 
 /// Group-only operations.
@@ -45,10 +49,6 @@ pub(crate) trait GroupConvo<S: ExternalServices>: Convo<S> + std::fmt::Debug + S
         members: &[IdentIdRef],
     ) -> Result<(), ChatError>;
 
-    /// Each current member's MLS leaf-credential content (hex-encoded), self
-    /// included.
-    fn members(&self) -> Result<Vec<Vec<u8>>, ChatError>;
-
     /// Each member this conversation invited and the group has not committed
     /// yet, in the same encoding as [`Self::members`]. Covers only invites
     /// [`Self::add_member`] made here, and is empty for a conversation kind

core/conversations/src/conversation/direct_v1.rs

@@ -61,4 +61,8 @@ where
     ) -> Result<crate::ConvoOutcome, ChatError> {
         self.inner_group.wakeup(service_ctx)
     }
+
+    fn members(&self) -> Result<Vec<Vec<u8>>, ChatError> {
+        Convo::<S>::members(&self.inner_group)
+    }
 }

core/conversations/src/conversation/group_v1.rs

@@ -295,6 +295,14 @@ impl<S: ExternalServices> Convo<S> for GroupV1Convo {
     fn wakeup(&mut self, _: &mut ServiceContext<S>) -> Result<ConvoOutcome, ChatError> {
         Ok(ConvoOutcome::empty(self.id().to_string()))
     }
+
+    fn members(&self) -> Result<Vec<Vec<u8>>, ChatError> {
+        Ok(self
+            .mls_group
+            .members()
+            .map(|m| m.credential.serialized_content().to_vec())
+            .collect())
+    }
 }
 
 impl<S: ExternalServices> GroupConvo<S> for GroupV1Convo {
@@ -344,14 +352,6 @@ impl<S: ExternalServices> GroupConvo<S> for GroupV1Convo {
         self.send_payload(cx, commit.to_bytes()?)
     }
 
-    fn members(&self) -> Result<Vec<Vec<u8>>, ChatError> {
-        Ok(self
-            .mls_group
-            .members()
-            .map(|m| m.credential.serialized_content().to_vec())
-            .collect())
-    }
-
     /// Always empty: `add_member` merges its own commit, so an added member is
     /// on the roster by the time the call returns.
     fn pending_members(&self) -> Result<Vec<Vec<u8>>, ChatError> {

core/conversations/src/conversation/group_v2.rs

@@ -291,6 +291,16 @@ where
         let events = self.after_op(ctx)?; // publish what poll produced + re-arm alarm
         Ok(self.outcome_from_events(&events))
     }
+
+    fn members(&self) -> Result<Vec<Vec<u8>>, ChatError> {
+        // Guarantee the local member is listed so callers see the full roster.
+        let mut members = self.conversation.members()?;
+        let self_id = self.conversation.member_id_bytes().to_vec();
+        if !members.contains(&self_id) {
+            members.push(self_id);
+        }
+        Ok(members)
+    }
 }
 
 impl<S> GroupConvo<S> for GroupV2Convo
@@ -376,16 +386,6 @@ where
         result.and(flushed)
     }
 
-    fn members(&self) -> Result<Vec<Vec<u8>>, ChatError> {
-        // Guarantee the local member is listed so callers see the full roster.
-        let mut members = self.conversation.members()?;
-        let self_id = self.conversation.member_id_bytes().to_vec();
-        if !members.contains(&self_id) {
-            members.push(self_id);
-        }
-        Ok(members)
-    }
-
     fn pending_members(&self) -> Result<Vec<Vec<u8>>, ChatError> {
         Ok(self
             .pending_invites

core/conversations/src/core.rs

@@ -263,52 +263,36 @@ impl<'a, S: ExternalServices + 'static> Core<S> {
         convo_id: &str,
         members: &[IdentIdRef],
     ) -> Result<(), ChatError> {
-        if self.cached_convos.contains_key(convo_id) {
-            let convo = self
-                .cached_convos
-                .get_mut(convo_id)
-                .ok_or_else(|| ChatError::NoConvo(convo_id.to_string()))?;
+        let convo = self
+            .cached_convos
+            .get_mut(convo_id)
+            .ok_or_else(|| ChatError::NoConvo(convo_id.to_string()))?;
 
-            match convo {
-                ConvoTypeOwned::Group(group_convo) => {
-                    group_convo.add_member(&mut self.services, members)
-                }
-                ConvoTypeOwned::Direct(convo) => Err(ChatError::UnsupportedFunction(
-                    convo.id().into(),
-                    "Add Member".into(),
-                )),
+        match convo {
+            ConvoTypeOwned::Group(group_convo) => {
+                group_convo.add_member(&mut self.services, members)
             }
-        } else {
-            let mut convo = self.load_group_convo(convo_id)?;
-            convo.add_member(&mut self.services, members)
+            ConvoTypeOwned::Direct(convo) => Err(ChatError::UnsupportedFunction(
+                convo.id().into(),
+                "Add Member".into(),
+            )),
         }
     }
 
-    /// Each member's MLS leaf-credential content (hex-encoded); errors if
-    /// `convo_id` names a direct (non-group) conversation.
+    /// Each member's MLS leaf-credential content (hex-encoded), for a direct
+    /// conversation as for a group.
     pub fn group_members(&mut self, convo_id: &str) -> Result<Vec<Vec<u8>>, ChatError> {
-        if self.cached_convos.contains_key(convo_id) {
-            let convo = self
-                .cached_convos
-                .get(convo_id)
-                .ok_or_else(|| ChatError::NoConvo(convo_id.to_string()))?;
+        let convo = self
+            .cached_convos
+            .get(convo_id)
+            .ok_or_else(|| ChatError::NoConvo(convo_id.to_string()))?;
 
-            match convo {
-                ConvoTypeOwned::Group(group_convo) => group_convo.members(),
-                ConvoTypeOwned::Direct(convo) => Err(ChatError::UnsupportedFunction(
-                    convo.id().into(),
-                    "List Members".into(),
-                )),
-            }
-        } else {
-            let convo = self.load_group_convo(convo_id)?;
-            convo.members()
-        }
+        convo.members()
     }
 
     /// Each member invited here and still awaiting the group's commit, in the
-    /// same encoding as [`Self::group_members`]; errors if `convo_id` names a
-    /// direct (non-group) conversation.
+    /// same encoding as [`Self::group_members`]. A direct conversation has no
+    /// pending members and reports none.
     pub fn group_pending_members(&mut self, convo_id: &str) -> Result<Vec<Vec<u8>>, ChatError> {
         let convo = self
             .cached_convos
@@ -317,10 +301,7 @@ impl<'a, S: ExternalServices + 'static> Core<S> {
 
         match convo {
             ConvoTypeOwned::Group(group_convo) => group_convo.pending_members(),
-            ConvoTypeOwned::Direct(convo) => Err(ChatError::UnsupportedFunction(
-                convo.id().into(),
-                "List Pending Members".into(),
-            )),
+            ConvoTypeOwned::Direct(_) => Ok(Vec::new()),
         }
     }
 
@@ -464,17 +445,6 @@ impl<'a, S: ExternalServices + 'static> Core<S> {
         })
     }
 
-    /// Rebuilds a group conversation; errors if `convo_id` names a non-group.
-    fn load_group_convo(&mut self, convo_id: &str) -> Result<Box<dyn GroupConvo<S>>, ChatError> {
-        let record = self.load_conversation_meta(convo_id)?;
-        match record.kind {
-            ConversationKind::GroupV1 => Ok(Box::new(self.load_mls_convo(&record.local_convo_id)?)),
-            ConversationKind::Unknown(_) => {
-                Err(ChatError::UnsupportedConvoType(record.kind.as_str().into()))
-            }
-        }
-    }
-
     /// Rebuilds a group conversation from storage so an operation can run against it.
     fn load_mls_convo(&mut self, convo_id: &str) -> Result<GroupV1Convo, ChatError> {
         let group_id_bytes = hex::decode(convo_id).map_err(ChatError::generic)?;
@@ -563,4 +533,11 @@ impl<S: ExternalServices> Convo<S> for ConvoTypeOwned<S> {
             ConvoTypeOwned::Direct(convo) => convo.wakeup(service_ctx),
         }
     }
+
+    fn members(&self) -> Result<Vec<Vec<u8>>, ChatError> {
+        match self {
+            ConvoTypeOwned::Group(group_convo) => group_convo.members(),
+            ConvoTypeOwned::Direct(convo) => convo.members(),
+        }
+    }
 }

crates/generic-chat/src/client.rs

@@ -229,14 +229,15 @@ where
             .map_err(Into::into)
     }
 
-    /// The group's roster, one [`GroupMember`] per account (self included),
-    /// committed members first and this client's uncommitted invites after
-    /// them, flagged `pending`. An account's several devices collapse to a
-    /// single entry surfacing that account; a member whose account claim the
-    /// directory can't confirm stays on the roster individually, keyed by its
-    /// device. An account that is both committed and pending collapses to its
-    /// committed entry. Costs one directory lookup per member that claims an
-    /// account, the same per-member cost a received message's sender check pays.
+    /// The conversation's roster, one [`GroupMember`] per account (self
+    /// included), for a direct conversation as for a group: committed members
+    /// first and this client's uncommitted invites after them, flagged
+    /// `pending`. An account's several devices collapse to a single entry
+    /// surfacing that account; a member whose account claim the directory can't
+    /// confirm stays on the roster individually, keyed by its device. An account
+    /// that is both committed and pending collapses to its committed entry.
+    /// Costs one directory lookup per member that claims an account, the same
+    /// per-member cost a received message's sender check pays.
     pub fn group_members(&mut self, convo_id: &str) -> Result<Vec<GroupMember>, ClientError> {
         let (committed, pending) = {
             let mut core = self.core.lock();

crates/generic-chat/tests/saro_and_raya.rs

@@ -304,6 +304,43 @@ fn group_metadata_on_direct_conversation_errors() {
         .expect_err("direct conversation has no group metadata");
 }
 
+/// A direct conversation reports its participants like any conversation. Add
+/// Member errors on the creator's handle, though the joiner holds the same
+/// conversation as a plain group, so the rejection is not conversation-wide.
+#[test]
+fn direct_conversation_lists_its_participants() {
+    let bus = MessageBus::default();
+    let reg = EphemeralRegistry::new();
+
+    let (mut saro, _saro_events) =
+        create_test_client(bus.clone(), reg.clone()).expect("client create");
+    let (raya, _raya_events) = create_test_client(bus.clone(), reg.clone()).expect("client create");
+
+    let saro_addr = saro.addr().to_string();
+    let raya_addr = raya.addr().to_string();
+    let convo_id = saro
+        .create_direct_conversation(&raya_addr)
+        .expect("convo create");
+
+    let roster = saro.group_members(&convo_id).expect("group_members");
+    let mut accounts: Vec<Option<&str>> = roster
+        .iter()
+        .map(|m| m.account.as_ref().map(|a| a.as_str()))
+        .collect();
+    accounts.sort();
+    let mut expected = vec![Some(saro_addr.as_str()), Some(raya_addr.as_str())];
+    expected.sort();
+    assert_eq!(accounts, expected);
+
+    let err = saro
+        .add_group_members(&convo_id, &[&raya_addr])
+        .expect_err("add member is unsupported on a direct conversation");
+    assert!(matches!(
+        err,
+        logos_generic_chat::ClientError::Chat(libchat::ChatError::UnsupportedFunction(..))
+    ));
+}
+
 #[derive(Debug)]
 struct FailingDelivery {
     inbound_tx: Sender<Vec<u8>>,