void (@NotNull IdeaPluginDescriptor pluginDescriptor, boolean isUpdate) { // `myIdToDirCache` could retain alien file systems clearIdCache(); // remove alien file system references from myRoots for (Iterator<Map.Entry<String, VirtualFileSystemEntry>> iterator = myRoots.entrySet().iterator(); iterator.hasNext(); ) { Map.Entry<String, VirtualFileSystemEntry> entry = iterator.next(); VirtualFileSystemEntry root = entry.getValue(); if (VirtualFileManager.getInstance().getFileSystem(root.getFileSystem().getProtocol()) == null) { // the file system must have been unregistered iterator.remove();//TODO RC: but entry in a .idToDirCache.myIdToRootCache -- still remains? } } }