rostopic list 报错 Traceback (most recent call last):

1. Problem description

  ROS, which has been running normally, suddenly rostopic listmakes an error and lacks files, as shown in the figure below.

Two, the solution

Concrete operation

  Missing file package link Extraction code: nu7j
  After downloading the above missing file package, decompress Cryptodome.tar.gzthe compressed package inside, copy Cryptodome文件夹, gnupg.py, gnupg.pycto /opt/ros/melodic/lib/python2.7/dist-packages/the path , and it can be used normally.