From 3478e691df49b9c0938220db57b03a9c6fcbec8d Mon Sep 17 00:00:00 2001
From: Kitsune Ral <Kitsune-Ral@users.sf.net>
Date: Wed, 14 Nov 2018 07:26:31 +0900
Subject: Room: fix incorrect handling of state event redactions

Also: use Matrix type instead of internal type id in StateEventKey
(Because internal type id maps to the library type system which will not
discern between Unknown events and therefore will mix together events of
different types in Room::Private::baseState/currentState. The Room code
is updated accordingly (bonus: more asserts there).)
Closes #255.
---
 lib/events/stateevent.h |  2 +-
 lib/room.cpp            | 39 ++++++++++++++++++++++++++++++---------
 2 files changed, 31 insertions(+), 10 deletions(-)

diff --git a/lib/events/stateevent.h b/lib/events/stateevent.h
index 76c749f5..d50500f2 100644
--- a/lib/events/stateevent.h
+++ b/lib/events/stateevent.h
@@ -42,7 +42,7 @@ namespace QMatrixClient {
      * of state in Matrix.
      * \sa https://matrix.org/docs/spec/client_server/unstable.html#types-of-room-events
      */
-    using StateEventKey = std::pair<Event::Type, QString>;
+    using StateEventKey = std::pair<QString, QString>;
 
     template <typename ContentT>
     struct Prev
diff --git a/lib/room.cpp b/lib/room.cpp
index fd4add3b..38a4157e 100644
--- a/lib/room.cpp
+++ b/lib/room.cpp
@@ -178,10 +178,12 @@ class Room::Private
         template <typename EventT>
         const EventT* getCurrentState(QString stateKey = {}) const
         {
-            static const EventT emptyEvent { QJsonObject{} };
-            return static_cast<const EventT*>(
-                        currentState.value({EventT::typeId(), stateKey},
-                                           &emptyEvent));
+            static const EventT empty;
+            const auto* evt =
+                currentState.value({EventT::matrixTypeId(), stateKey}, &empty);
+            Q_ASSERT(evt->type() == EventT::typeId() &&
+                     evt->matrixType() == EventT::matrixTypeId());
+            return static_cast<const EventT*>(evt);
         }
 
         bool isEventNotable(const TimelineItem& ti) const
@@ -1117,7 +1119,8 @@ void Room::updateData(SyncRoomData&& data)
         for (auto&& eptr: data.state)
         {
             const auto& evt = *eptr;
-            d->baseState[{evt.type(),evt.stateKey()}] = move(eptr);
+            Q_ASSERT(evt.isStateEvent());
+            d->baseState[{evt.matrixType(),evt.stateKey()}] = move(eptr);
             emitNamesChanged |= processStateEvent(evt);
         }
 
@@ -1628,11 +1631,26 @@ bool Room::Private::processRedaction(const RedactionEvent& redaction)
         return true;
     }
 
-    // Make a new event from the redacted JSON, exchange events,
-    // notify everyone and delete the old event
+    // Make a new event from the redacted JSON and put it in the timeline
+    // instead of the redacted one. oldEvent will be deleted on return.
     auto oldEvent = ti.replaceEvent(makeRedacted(*ti, redaction));
-    q->onRedaction(*oldEvent, *ti.event());
     qCDebug(MAIN) << "Redacted" << oldEvent->id() << "with" << redaction.id();
+    if (oldEvent->isStateEvent())
+    {
+        const StateEventKey evtKey { oldEvent->matrixType(), oldEvent->stateKey() };
+        Q_ASSERT(currentState.contains(evtKey));
+        if (currentState[evtKey] == oldEvent.get())
+        {
+            Q_ASSERT(ti.index() >= 0); // Historical states can't be in currentState
+            qCDebug(MAIN).nospace() << "Reverting state "
+                << oldEvent->matrixType() << "/" << oldEvent->stateKey();
+            // Retarget the current state to the newly made event.
+            if (q->processStateEvent(*ti))
+                emit q->namesChanged(q);
+            updateDisplayname();
+        }
+    }
+    q->onRedaction(*oldEvent, *ti);
     emit q->replacedEvent(ti.event(), rawPtr(oldEvent));
     return true;
 }
@@ -1791,7 +1809,7 @@ bool Room::processStateEvent(const RoomEvent& e)
     if (!e.isStateEvent())
         return false;
 
-    d->currentState[{e.type(),e.stateKey()}] =
+    d->currentState[{e.matrixType(),e.stateKey()}] =
             static_cast<const StateEventBase*>(&e);
     if (!is<RoomMemberEvent>(e))
         qCDebug(EVENTS) << "Room state event:" << e;
@@ -2060,7 +2078,10 @@ QJsonObject Room::Private::toJson() const
         QJsonArray stateEvents;
 
         for (const auto& evt: currentState)
+        {
+            Q_ASSERT(evt->isStateEvent());
             stateEvents.append(evt->fullJson());
+        }
 
         const auto stateObjName = joinState == JoinState::Invite ?
                     QStringLiteral("invite_state") : QStringLiteral("state");
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