message: verilog: tools: ls: lsp-parse-buffer: Added mention that BufferTracker can be nullptr in modification callback
diff: @@ -87,11 +87,17 @@ class BufferTrackerContainer {
  verible::lsp::BufferCollection::UriBufferCallback GetSubscriptionCallback();
  // type for buffer change callback function
  + // The callback takes uri of the file, and the pointer to the BufferTracker
  + // The pointer can be nullptr, meaning that e.g. the file was closed.
  + // The nullptr case should be handled by callback.
  using ChangeCallback =
  std::function<void(const std::string &uri, const BufferTracker *tracker)>;
  // Add a change listener for clients of ours interested in updated fresly
  // parsed content.
  + // The callback takes uri of the file, and the pointer to the BufferTracker
  + // The pointer can be nullptr, meaning that e.g. the file was closed.
  + // The nullptr case should be handled by callback.
  void AddChangeListener(const ChangeCallback &cb) {
  change_listeners_.push_back(ABSL_DIE_IF_NULL(cb));
  }
  