RtpSessionActivity: throw instead of finish when session wasn’t found

src/main/java/eu/siacs/conversations/ui/RtpSessionActivity.java

@@ -412,14 +412,12 @@ public class RtpSessionActivity extends XmppActivity implements XmppConnectionSe
         final WeakReference<JingleRtpConnection> reference = xmppConnectionService.getJingleConnectionManager()
                 .findJingleRtpConnection(account, with, sessionId);
         if (reference == null || reference.get() == null) {
-            Log.e(Config.LOGTAG,"failed to initialize activity with running rtp session. session not found");
+            throw new IllegalStateException("failed to initialize activity with running rtp session. session not found");
-            finish();
-            return true;
         }
         this.rtpConnectionReference = reference;
         final RtpEndUserState currentState = requireRtpConnection().getEndUserState();
         if (currentState == RtpEndUserState.ENDED) {
-            Log.e(Config.LOGTAG,"failed to initialize activity with running rtp session. session had ended");
+            reference.get().throwStateTransitionException();
             finish();
             return true;
         }

src/main/java/eu/siacs/conversations/xmpp/jingle/JingleRtpConnection.java

@@ -123,6 +123,7 @@ public class JingleRtpConnection extends AbstractJingleConnection implements Web
     private final ArrayDeque<IceCandidate> pendingIceCandidates = new ArrayDeque<>();
     private final Message message;
     private State state = State.NULL;
+    private StateTransitionException stateTransitionException;
     private Set<Media> proposedMedia;
     private RtpContentMap initiatorRtpContentMap;
     private RtpContentMap responderRtpContentMap;
@@ -771,6 +772,13 @@ public class JingleRtpConnection extends AbstractJingleConnection implements Web
         xmppConnectionService.sendIqPacket(id.account, jinglePacket.generateResponse(IqPacket.TYPE.RESULT), null);
     }
 
+    public void throwStateTransitionException() {
+        final StateTransitionException exception = this.stateTransitionException;
+        if (exception != null) {
+            throw new IllegalStateException(String.format("Transition to %s did not call finish", exception.state), exception);
+        }
+    }
+
     public RtpEndUserState getEndUserState() {
         switch (this.state) {
             case PROPOSED:
@@ -983,6 +991,7 @@ public class JingleRtpConnection extends AbstractJingleConnection implements Web
         final Collection<State> validTransitions = VALID_TRANSITIONS.get(this.state);
         if (validTransitions != null && validTransitions.contains(target)) {
             this.state = target;
+            this.stateTransitionException = new StateTransitionException(target);
             if (runnable != null) {
                 runnable.run();
             }
@@ -1231,4 +1240,12 @@ public class JingleRtpConnection extends AbstractJingleConnection implements Web
     private interface OnIceServersDiscovered {
         void onIceServersDiscovered(List<PeerConnection.IceServer> iceServers);
     }
+
+    private static class StateTransitionException extends Exception {
+        private final State state;
+
+        private StateTransitionException(final State state) {
+            this.state = state;
+        }
+    }
 }