Rewrite disambiguation algorithm to handle profile changes.

The new algorithm is simpler. Instead of tracking a list of
disambiguated display names in `Room`, we instead track the display name
ambiguity status in `RoomMember`. This allows a client to generate the
correct name for a member using solely the information available in
`RoomMember`.

The disambiguation algorithm itself now only calculates the set of members
whose ambiguity status had changed instead of producing disambiguated
display names for everyone affected. This is called on each room entry
(join or invite), room entry and profile change, and the updates are
propagated to the affected `RoomMember`s.

matrix_sdk_base/Cargo.toml

@@ -21,6 +21,7 @@ async-trait = "0.1.31"
 serde = "1.0.110"
 serde_json = "1.0.53"
 zeroize = "1.1.0"
+tracing = "0.1.14"
 
 matrix-sdk-common-macros = { version = "0.1.0", path = "../matrix_sdk_common_macros" }
 matrix-sdk-common = { version = "0.1.0", path = "../matrix_sdk_common" }

matrix_sdk_base/src/client.rs

@@ -734,7 +734,7 @@ impl BaseClient {
                 let mut room = room_lock.write().await;
 
                 if let RoomEvent::RoomMember(mem_event) = &mut e {
-                    let changed = room.handle_membership(mem_event);
+                    let (changed, _) = room.handle_membership(mem_event);
 
                     // The memberlist of the room changed, invalidate the group session
                     // of the room.
@@ -771,7 +771,7 @@ impl BaseClient {
         let mut room = room_lock.write().await;
 
         if let StateEvent::RoomMember(e) = event {
-            let changed = room.handle_membership(e);
+            let (changed, _) = room.handle_membership(e);
 
             // The memberlist of the room changed, invalidate the group session
             // of the room.

matrix_sdk_base/src/models/message.rs

@@ -178,7 +178,6 @@ mod test {
             serde_json::json!({
                 "!roomid:example.com": {
                     "room_id": "!roomid:example.com",
-                    "disambiguated_display_names": {},
                     "room_name": {
                         "name": null,
                         "canonical_alias": null,
@@ -229,7 +228,6 @@ mod test {
         let json = serde_json::json!({
             "!roomid:example.com": {
                 "room_id": "!roomid:example.com",
-                "disambiguated_display_names": {},
                 "room_name": {
                     "name": null,
                     "canonical_alias": null,

matrix_sdk_base/src/models/room.rs

@@ -14,10 +14,11 @@
 // limitations under the License.
 
 use std::borrow::Cow;
-use std::collections::{BTreeMap, HashMap};
+use std::collections::{BTreeMap, HashMap, HashSet};
 use std::convert::TryFrom;
 
 use serde::{Deserialize, Serialize};
+use tracing::{debug, error, trace};
 
 #[cfg(feature = "messages")]
 use super::message::MessageQueue;
@@ -30,7 +31,7 @@ use crate::events::room::{
     aliases::AliasesEvent,
     canonical_alias::CanonicalAliasEvent,
     encryption::EncryptionEvent,
-    member::{MemberEvent, MembershipChange},
+    member::{MemberEvent, MembershipChange, MembershipState},
     name::NameEvent,
     power_levels::{NotificationPowerLevels, PowerLevelsEvent, PowerLevelsEventContent},
     tombstone::TombstoneEvent,
@@ -146,12 +147,6 @@ pub struct Tombstone {
     replacement: RoomId,
 }
 
-#[derive(Debug, PartialEq, Eq)]
-enum MemberDirection {
-    Entering,
-    Exiting,
-}
-
 #[derive(Debug, PartialEq, Serialize, Deserialize, Clone)]
 /// A Matrix room.
 pub struct Room {
@@ -188,8 +183,6 @@ pub struct Room {
     pub unread_notifications: Option<UInt>,
     /// The tombstone state of this room.
     pub tombstone: Option<Tombstone>,
-    /// The map of disambiguated display names for users who have the same display name
-    disambiguated_display_names: HashMap<UserId, String>,
 }
 
 impl RoomName {
@@ -302,7 +295,6 @@ impl Room {
             unread_highlight: None,
             unread_notifications: None,
             tombstone: None,
-            disambiguated_display_names: HashMap::new(),
         }
     }
 
@@ -329,191 +321,231 @@ impl Room {
 
     /// Get the disambiguated display name for a member of this room.
     ///
-    /// If a member has no display name set, returns the MXID as a fallback. Additionally, we
+    /// If a member has no display name set, returns the MXID as a fallback.
-    /// return the MXID even if there is no such member in the room.
+    ///
+    /// This method never fails, even if user with the supplied MXID is not a member in the room.
+    /// In this case we still return the supplied MXID as a fallback.
     ///
     /// When displaying a room member's display name, clients *must* use this method to obtain the
     /// name instead of displaying the `RoomMember::display_name` directly. This is because
     /// multiple members can share the same display name in which case the display name has to be
     /// disambiguated.
     pub fn member_display_name<'a>(&'a self, id: &'a UserId) -> Cow<'a, str> {
-        let disambiguated_name = self
+        let member = self.get_member(id);
-            .disambiguated_display_names
-            .get(id)
-            .map(|s| s.as_str().into());
 
-        if let Some(name) = disambiguated_name {
+        match member {
-            // The display name of the member is non-unique so we return a disambiguated version.
+            Some(member) => {
-            name
+                if member.display_name_ambiguous {
-        } else if let Some(member) = self
+                    member.unique_name().into()
-            .joined_members
-            .get(id)
-            .or_else(|| self.invited_members.get(id))
-        {
-            // The display name of the member is unique so we can return it directly if it is set.
-            // If not, we return his MXID.
-            member.name().into()
                 } else {
-            // There is no member with the requested MXID in the room. We still return the MXID.
+                    member.name().into()
-            id.as_ref().into()
                 }
             }
 
-    /// Process the member event of an entering user.
+            // Even if there is no such member, we return the MXID that was given to us.
+            None => id.as_ref().into(),
+        }
+    }
+
+    /// Process the join or invite event for a new room member.
     ///
-    /// Returns true if this made a change to the room's state, false otherwise.
+    /// If the user is not already a member, he will be added. Otherwise, his state will be updated
-    fn add_member(&mut self, event: &MemberEvent) -> bool {
+    /// to reflect the event's state.
+    ///
+    /// Returns a tuple of:
+    ///
+    /// 1. True if the event made changes to the room's state, false otherwise.
+    /// 2. Returns a map of display name disambiguations which tells us which members need to have
+    ///    their display names disambiguated and to what.
+    ///
+    /// # Arguments
+    ///
+    /// * `target_member` - The ID of the member to add.
+    /// * `event` - The join or invite event for the specified room member.
+    fn add_member(
+        &mut self,
+        target_member: &UserId,
+        event: &MemberEvent,
+    ) -> (bool, HashMap<UserId, bool>) {
         let new_member = RoomMember::new(event);
 
-        match event.membership_change() {
-            MembershipChange::Joined => {
-                // Since the member is now joined, he shouldn't be tracked as an invited member any
-                // longer.
-                if self.invited_members.contains_key(&new_member.user_id) {
-                    self.invited_members.remove(&new_member.user_id);
-                }
-
-                self.joined_members
-                    .insert(new_member.user_id.clone(), new_member.clone())
-            }
-
-            MembershipChange::Invited => self
-                .invited_members
-                .insert(new_member.user_id.clone(), new_member.clone()),
-
-            _ => {
-                panic!("Room::add_member called on an event that is neither a join nor an invite.")
-            }
-        };
-
-        // Perform display name disambiguations, if necessary.
-        let disambiguations = self.disambiguation_updates(&new_member, MemberDirection::Entering);
-        for (id, name) in disambiguations.into_iter() {
-            match name {
-                None => self.disambiguated_display_names.remove(&id),
-                Some(name) => self.disambiguated_display_names.insert(id, name),
-            };
-        }
-
-        true
-    }
-
-    /// Process the member event of a leaving user.
-    ///
-    /// Returns true if this made a change to the room's state, false otherwise.
-    fn remove_member(&mut self, event: &MemberEvent) -> bool {
-        let leaving_member = RoomMember::new(event);
-
         // Perform display name disambiguations, if necessary.
         let disambiguations =
-            self.disambiguation_updates(&leaving_member, MemberDirection::Exiting);
+            self.ambiguity_updates(target_member, None, new_member.display_name.clone());
-        for (id, name) in disambiguations.into_iter() {
+
-            match name {
+        debug!("add_member: disambiguations: {:#?}", disambiguations);
-                None => self.disambiguated_display_names.remove(&id),
+
-                Some(name) => self.disambiguated_display_names.insert(id, name),
+        match event.content.membership {
+            MembershipState::Join => {
+                // Since the member is now joined, he shouldn't be tracked as an invited member any
+                // longer if he was previously tracked as such.
+                self.invited_members.remove(target_member);
+
+                self.joined_members
+                    .insert(target_member.clone(), new_member.clone())
+            }
+
+            MembershipState::Invite => self
+                .invited_members
+                .insert(target_member.clone(), new_member.clone()),
+
+            _ => panic!("Room::add_member called on event that is neither `join` nor `invite`."),
         };
+
+        for (id, is_ambiguous) in disambiguations.iter() {
+            self.get_member_mut(id).unwrap().display_name_ambiguous = *is_ambiguous;
         }
 
-        if self.joined_members.contains_key(&leaving_member.user_id) {
+        (true, disambiguations)
-            self.joined_members.remove(&leaving_member.user_id);
-            true
-        } else if self.invited_members.contains_key(&leaving_member.user_id) {
-            self.invited_members.remove(&leaving_member.user_id);
-            true
-        } else {
-            false
-        }
     }
 
-    /// Given a room `member`, return the list of members which have the same display name.
+    /// Process the leaving event for a room member.
     ///
-    /// The `inclusive` parameter controls whether the passed member should be included in the
+    /// Returns a tuple of:
-    /// list or not.
+    ///
-    fn shares_displayname_with(&self, member: &RoomMember, inclusive: bool) -> Vec<RoomMember> {
+    /// 1. True if the event made changes to the room's state, false otherwise.
+    /// 2. Returns a map of display name disambiguations which tells us which members need to have
+    ///    their display names disambiguated and to what.
+    ///
+    /// # Arguments
+    ///
+    /// * `target_member` - The ID of the member to remove.
+    /// * `event` - The leaving event for the specified room member.
+    fn remove_member(
+        &mut self,
+        target_member: &UserId,
+        event: &MemberEvent,
+    ) -> (bool, HashMap<UserId, bool>) {
+        let leaving_member = RoomMember::new(event);
+
+        if self.get_member(target_member).is_none() {
+            return (false, HashMap::new());
+        }
+
+        // Perform display name disambiguations, if necessary.
+        let disambiguations =
+            self.ambiguity_updates(target_member, leaving_member.display_name.clone(), None);
+
+        debug!("remove_member: disambiguations: {:#?}", disambiguations);
+
+        for (id, is_ambiguous) in disambiguations.iter() {
+            self.get_member_mut(id).unwrap().display_name_ambiguous = *is_ambiguous;
+        }
+
+        // TODO: factor this out to a method called `remove_member` and rename this method
+        // to something like `process_member_leaving_event`.
+        self.joined_members
+            .remove(target_member)
+            .or_else(|| self.invited_members.remove(target_member));
+
+        (true, disambiguations)
+    }
+
+    /// Check whether the user with the MXID `user_id` is joined or invited to the room.
+    ///
+    /// Returns true if so, false otherwise.
+    pub fn member_is_tracked(&self, user_id: &UserId) -> bool {
+        self.invited_members.contains_key(&user_id) || self.joined_members.contains_key(&user_id)
+    }
+
+    /// Get a room member by user ID.
+    ///
+    /// If there is no such member, returns `None`.
+    pub fn get_member(&self, user_id: &UserId) -> Option<&RoomMember> {
+        self.joined_members
+            .get(user_id)
+            .or_else(|| self.invited_members.get(user_id))
+    }
+
+    /// Get a room member by user ID.
+    ///
+    /// If there is no such member, returns `None`.
+    pub fn get_member_mut(&mut self, user_id: &UserId) -> Option<&mut RoomMember> {
+        match self.joined_members.get_mut(user_id) {
+            None => self.invited_members.get_mut(user_id),
+            Some(m) => Some(m),
+        }
+    }
+
+    /// Given a display name, return the set of members which share it.
+    fn display_name_equivalence_class(&self, name: &str) -> HashSet<UserId> {
         let members = self
             .invited_members
             .iter()
             .chain(self.joined_members.iter());
 
-        // Find all other users that share the same display name as the joining user.
+        // Find all other users that share the display name with the joining user.
         members
-            .filter(|(_, existing_member)| {
+            .filter(|(_, member)| {
                 member
                     .display_name
                     .as_ref()
-                    .and_then(|new_member_name| {
+                    .map(|other_name| other_name == name)
-                        existing_member
-                            .display_name
-                            .as_ref()
-                            .map(|existing_member_name| new_member_name == existing_member_name)
-                    })
                     .unwrap_or(false)
             })
-            // If not an inclusive search, do not consider the member for which we are disambiguating.
+            .map(|(_, member)| member.user_id.clone())
-            .filter(|(id, _)| inclusive || **id != member.user_id)
-            .map(|(_, member)| member)
-            .cloned()
             .collect()
     }
 
-    /// Given a room member, generate a map of all display name disambiguations which are necessary
+    /// Given a change in a member's display name, determine the set of members whose display names
-    /// in order to make that member's display name unique.
+    /// would either become newly ambiguous or no longer ambiguous after the change.
     ///
-    /// The `inclusive` parameter controls whether or not the member for which we are
+    /// Returns a map of `user` -> `ambiguity` for affected room member. If `ambiguity` is `true`,
-    /// disambiguating should be considered a current member of the room.
+    /// the member's display name is newly ambiguous after the change. If `false`, their display
+    /// name is no longer ambiguous (but it was before).
     ///
-    /// Returns a map from MXID to disambiguated name.
+    /// The method *must* be called before any actual display name changes are performed in our
-    fn member_disambiguations(
+    /// model (e.g. the `RoomMember` structs).
+    ///
+    /// # Arguments
+    ///
+    /// * `member` - The ID of the member changing their display name.
+    /// * `old_name` - Their old display name, prior to the change. May be `None` if they had no
+    /// display name in this room (e.g. because it was unset or because they were not a room
+    /// member).
+    /// * `new_name` - Their new display name, after the change. May be `None` if they are no
+    /// longer going to have a display name in this room after the change (e.g. because they are
+    /// unsetting it or leaving the room).
+    ///
+    /// Returns a map from user ID to the new ambiguity status.
+    fn ambiguity_updates(
         &self,
-        member: &RoomMember,
+        member: &UserId,
-        inclusive: bool,
+        old_name: Option<String>,
-    ) -> HashMap<UserId, String> {
+        new_name: Option<String>,
-        let users_with_same_name = self.shares_displayname_with(member, inclusive);
+    ) -> HashMap<UserId, bool> {
+        // Must be called *before* any changes to the model.
 
-        let disambiguate_with = |members: Vec<RoomMember>, f: fn(&RoomMember) -> String| {
+        let old_name_eq_class = match old_name {
-            members
+            None => HashSet::new(),
-                .into_iter()
+            Some(name) => self.display_name_equivalence_class(&name),
-                .map(|ref m| (m.user_id.clone(), f(m)))
-                .collect::<HashMap<UserId, String>>()
         };
 
-        match users_with_same_name.len() {
+        let disambiguate_old = match old_name_eq_class.len().saturating_sub(1) {
-            0 | 1 => HashMap::new(),
+            n if n > 1 => vec![(member.clone(), false)].into_iter().collect(),
-            _ => disambiguate_with(users_with_same_name, |m: &RoomMember| m.unique_name()),
+            1 => old_name_eq_class.into_iter().map(|m| (m, false)).collect(),
-        }
+            0 => HashMap::new(),
-    }
+            _ => panic!("impossible"),
+        };
 
-    /// Calculate disambiguation updates needed when a room member either enters or exits.
+        //
-    fn disambiguation_updates(
-        &self,
-        member: &RoomMember,
-        when: MemberDirection,
-    ) -> HashMap<UserId, Option<String>> {
-        let before;
-        let after;
 
-        match when {
+        let mut new_name_eq_class = match new_name {
-            MemberDirection::Entering => {
+            None => HashSet::new(),
-                before = self.member_disambiguations(member, false);
+            Some(name) => self.display_name_equivalence_class(&name),
-                after = self.member_disambiguations(member, true);
+        };
-            }
-            MemberDirection::Exiting => {
-                before = self.member_disambiguations(member, true);
-                after = self.member_disambiguations(member, false);
-            }
-        }
 
-        let mut res = before;
+        new_name_eq_class.insert(member.clone());
-        res.extend(after.clone());
 
-        res.into_iter()
+        let disambiguate_new = match new_name_eq_class.len() {
-            .map(|(user_id, name)| {
+            1 => HashMap::new(),
-                if !after.contains_key(&user_id) {
+            2 => new_name_eq_class.into_iter().map(|m| (m, true)).collect(),
-                    (user_id, None)
+            _ => vec![(member.clone(), true)].into_iter().collect(),
-                } else {
+        };
-                    (user_id, Some(name))
+
-                }
+        disambiguate_old
-            })
+            .into_iter()
+            .chain(disambiguate_new.into_iter())
             .collect()
     }
 
@@ -581,23 +613,69 @@ impl Room {
 
     /// Handle a room.member updating the room state if necessary.
     ///
-    /// Returns true if the joined member list changed, false otherwise.
+    /// Returns a tuple of:
-    pub fn handle_membership(&mut self, event: &MemberEvent) -> bool {
+    ///
+    /// 1. True if the joined member list changed, false otherwise.
+    /// 2. A map of display name disambiguations which tells us which members need to have their
+    ///    display names disambiguated and to what.
+    pub fn handle_membership(
+        &mut self,
+        event: &MemberEvent,
+        state_event: bool,
+    ) -> (bool, HashMap<UserId, bool>) {
         use MembershipChange::*;
+        use MembershipState::*;
 
-        match event.membership_change() {
+        trace!(
-            Invited | Joined => {
+            "Received {} event: {}",
-                self.add_member(event)
+            if state_event { "state" } else { "timeline" },
+            event.event_id
+        );
+
+        let target_user = match UserId::try_from(event.state_key.clone()) {
+            Ok(id) => id,
+            Err(e) => {
+                error!("Received a member event with invalid state_key: {}", e);
+                return (false, HashMap::new());
             }
+        };
+
+        if state_event && !self.member_is_tracked(&target_user) {
+            debug!(
+                "handle_membership: User {user_id} is {state} the room {room_id} ({room_name})",
+                user_id = target_user,
+                state = event.content.membership.describe(),
+                room_id = self.room_id,
+                room_name = self.display_name(),
+            );
+
+            match event.content.membership {
+                Join | Invite => self.add_member(&target_user, event),
+
+                // We are not interested in tracking past members for now
+                _ => (false, HashMap::new()),
+            }
+        } else {
+            let change = event.membership_change();
+
+            debug!(
+                "handle_membership: User {user_id} {action} the room {room_id} ({room_name})",
+                user_id = target_user,
+                action = change.describe(),
+                room_id = self.room_id,
+                room_name = self.display_name(),
+            );
+
+            match change {
+                Invited | Joined => self.add_member(&target_user, event),
                 Kicked | Banned | KickedAndBanned | InvitationRejected | Left => {
-                self.remove_member(event)
+                    self.remove_member(&target_user, event)
-            }
-            ProfileChanged => {
-                self.update_member_profile(event)
                 }
+                ProfileChanged => self.update_member_profile(&target_user, event),
 
                 // Not interested in other events.
-            _ => false,
+                _ => (false, HashMap::new()),
+            }
         }
     }
 
@@ -697,7 +775,7 @@ impl Room {
     pub fn receive_timeline_event(&mut self, event: &RoomEvent) -> bool {
         match event {
             // update to the current members of the room
-            RoomEvent::RoomMember(member) => self.handle_membership(member),
+            RoomEvent::RoomMember(member) => self.handle_membership(member, false).0,
             // finds all events related to the name of the room for later use
             RoomEvent::RoomName(name) => self.handle_room_name(name),
             RoomEvent::RoomCanonicalAlias(c_alias) => self.handle_canonical(c_alias),
@@ -722,7 +800,7 @@ impl Room {
     pub fn receive_state_event(&mut self, event: &StateEvent) -> bool {
         match event {
             // update to the current members of the room
-            StateEvent::RoomMember(member) => self.handle_membership(member),
+            StateEvent::RoomMember(member) => self.handle_membership(member, true).0,
             // finds all events related to the name of the room for later use
             StateEvent::RoomName(name) => self.handle_room_name(name),
             StateEvent::RoomCanonicalAlias(c_alias) => self.handle_canonical(c_alias),
@@ -777,8 +855,8 @@ impl Room {
                 && member.presence.as_ref() == Some(presence)
                 && member.status_msg == *status_msg
                 && member.last_active_ago == *last_active_ago
-                && member.currently_active == *currently_active {
+                && member.currently_active == *currently_active
-
+            {
                 // Everything is the same, nothing to do.
                 false
             } else {
@@ -799,33 +877,70 @@ impl Room {
             // we don't know about.
             false
         }
-
     }
 
     /// Process an update of a member's profile.
     ///
+    /// Returns a tuple of:
+    ///
+    /// 1. True if the event made changes to the room's state, false otherwise.
+    /// 2. A map of display name disambiguations which tells us which members need to have their
+    ///    display names disambiguated and to what.
+    ///
     /// # Arguments
     ///
-    /// * `event` - The profile update event for a specified room member.
+    /// * `target_member` - The ID of the member to update.
-    // TODO: NEXT: Add disambiguation handling here
+    /// * `event` - The profile update event for the specified room member.
-    pub(crate) fn update_member_profile(&mut self, event: &MemberEvent) -> bool {
+    pub fn update_member_profile(
-        let user_id = if let Ok(id) = UserId::try_from(event.state_key.as_str()) {
+        &mut self,
-            id
+        target_member: &UserId,
-        } else {
+        event: &MemberEvent,
-            return false;
+    ) -> (bool, HashMap<UserId, bool>) {
-        };
+        let old_name = self
+            .get_member(target_member)
+            .map_or_else(|| None, |m| m.display_name.clone());
+        let new_name = event.content.displayname.clone();
 
-        if let Some(member) = self.joined_members.get_mut(&user_id) {
+        debug!(
-            member.display_name = event.content.displayname.clone();
+            "update_member_profile [{}]: from nick {:#?} to nick {:#?}",
-            member.avatar_url = event.content.avatar_url.clone();
+            self.room_id, old_name, &new_name
-            true
+        );
-        } else if let Some(member) = self.invited_members.get_mut(&user_id) {
+
-            member.display_name = event.content.displayname.clone();
+        let disambiguations =
-            member.avatar_url = event.content.avatar_url.clone();
+            self.ambiguity_updates(target_member, old_name.clone(), new_name.clone());
-            true
+        for (id, is_ambiguous) in disambiguations.iter() {
+            if self.get_member_mut(id).is_none() {
+                error!("update_member_profile: I'm about to fail for id {}. user_id = {}\nevent = {:#?}",
+                       id,
+                       target_member,
+                       event);
             } else {
+                self.get_member_mut(id).unwrap().display_name_ambiguous = *is_ambiguous;
+            }
+        }
+
+        debug!(
+            "update_member_profile [{}]: disambiguations: {:#?}",
+            self.room_id, &disambiguations
+        );
+
+        let changed = match self.get_member_mut(target_member) {
+            Some(member) => {
+                member.display_name = new_name;
+                member.avatar_url = event.content.avatar_url.clone();
+                true
+            }
+            None => {
+                error!(
+                    "update_member_profile [{}]: user {} does not exist",
+                    self.room_id, target_member
+                );
+
                 false
             }
+        };
+
+        (changed, disambiguations)
     }
 
     /// Process an update of a member's power level.
@@ -858,6 +973,48 @@ impl Room {
     }
 }
 
+trait Describe {
+    fn describe(&self) -> String;
+}
+
+impl Describe for MembershipState {
+    fn describe(&self) -> String {
+        use MembershipState::*;
+
+        match self {
+            Ban => "is banned in",
+            Invite => "is invited to",
+            Join => "is a member of",
+            Knock => "is requesting access",
+            Leave => "left",
+        }
+        .to_string()
+    }
+}
+
+impl Describe for MembershipChange {
+    fn describe(&self) -> String {
+        use MembershipChange::*;
+
+        match self {
+            Invited => "got invited to",
+            Joined => "joined",
+            Kicked => "got kicked from",
+            Banned => "got banned from",
+            Unbanned => "got unbanned from",
+            KickedAndBanned => "got kicked and banned from",
+            InvitationRejected => "rejected the invitation to",
+            InvitationRevoked => "got their invitation revoked from",
+            Left => "left",
+            ProfileChanged => "changed their profile",
+            None => "did nothing in",
+            NotImplemented => "NOT IMPLEMENTED",
+            Error => "ERROR",
+        }
+        .to_string()
+    }
+}
+
 #[cfg(test)]
 mod test {
     use super::*;

matrix_sdk_base/src/models/room_member.rs

@@ -33,6 +33,8 @@ pub struct RoomMember {
     pub user_id: UserId,
     /// The human readable name of the user.
     pub display_name: Option<String>,
+    /// Whether the member's display name is ambiguous due to being shared with other members.
+    pub display_name_ambiguous: bool,
     /// The matrix url of the users avatar.
     pub avatar_url: Option<String>,
     /// The time, in ms, since the user interacted with the server.
@@ -76,6 +78,7 @@ impl PartialEq for RoomMember {
             && self.user_id == other.user_id
             && self.name == other.name
             && self.display_name == other.display_name
+            && self.display_name_ambiguous == other.display_name_ambiguous
             && self.avatar_url == other.avatar_url
             && self.last_active_ago == other.last_active_ago
     }
@@ -88,6 +91,7 @@ impl RoomMember {
             room_id: event.room_id.as_ref().map(|id| id.to_string()),
             user_id: UserId::try_from(event.state_key.as_str()).unwrap(),
             display_name: event.content.displayname.clone(),
+            display_name_ambiguous: false,
             avatar_url: event.content.avatar_url.clone(),
             presence: None,
             status_msg: None,

matrix_sdk_base/src/state/mod.rs

@@ -159,7 +159,6 @@ mod test {
                     "creator": null,
                     "joined_members": {},
                     "invited_members": {},
-                    "disambiguated_display_names": {},
                     "typing_users": [],
                     "power_levels": null,
                     "encrypted": null,
@@ -176,7 +175,6 @@ mod test {
             serde_json::json!({
                 "!roomid:example.com": {
                     "room_id": "!roomid:example.com",
-                    "disambiguated_display_names": {},
                     "room_name": {
                         "name": null,
                         "canonical_alias": null,