Merge pull request #4509 from matrix-org/bwindels/dontencryptfor3pids

Don't enable e2ee when inviting a 3pid

src/components/views/dialogs/InviteDialog.js

@@ -577,12 +577,15 @@ export default class InviteDialog extends React.PureComponent {
         if (SettingsStore.getValue("feature_cross_signing")) {
             // Check whether all users have uploaded device keys before.
             // If so, enable encryption in the new room.
+            const has3PidMembers = targets.some(t => t instanceof ThreepidMember);
+            if (!has3PidMembers) {
                 const client = MatrixClientPeg.get();
                 const allHaveDeviceKeys = await canEncryptToAllUsers(client, targetIds);
                 if (allHaveDeviceKeys) {
                     createRoomOptions.encryption = true;
                 }
             }
+        }
 
         // Check if it's a traditional DM and create the room if required.
         // TODO: [Canonical DMs] Remove this check and instead just create the multi-person DM