a crash fix on one of archive corner cases

CHANGELOG.md

@@ -4,6 +4,7 @@
 ### Bug fixes
 - now when you remove an account it actually gets removed
 - segfault on unitialized Availability in some rare occesions
+- fixed crash when you open a dialog with someone that has only error messages in archive
 
 ### Improvements
 - there is a way to disable an account and it wouldn't connect when you change availability

core/rosteritem.cpp

@@ -124,6 +124,7 @@ void Core::RosterItem::nextRequest()
         if (requestedCount != -1) {
             bool last = false;
             if (archiveState == beginning || archiveState == complete) {
+                try {
                     QString firstId = archive->oldestId();
                     if (responseCache.size() == 0) {
                         if (requestedBefore == firstId) {
@@ -134,6 +135,9 @@ void Core::RosterItem::nextRequest()
                             last = true;
                         }
                     }
+                } catch (const Archive::Empty& e) {
+                    last = true;
+                }
             } else if (archiveState == empty && responseCache.size() == 0) {
                 last = true;
             }
@@ -171,8 +175,12 @@ void Core::RosterItem::performRequest(int count, const QString& before)
                 requestCache.emplace_back(requestedCount, before);
                 requestedCount = -1;
             }
+            try {
                 Shared::Message msg = archive->newest();
                 emit needHistory("", getId(msg), msg.getTime());
+            } catch (const Archive::Empty& e) {                     //this can happen when the only message in archive is not server stored (error, for example)
+                emit needHistory(before, "");
+            }
         }
             break;
         case end: