ROS Resources: Documentation | Support | Discussion Forum | Index | Service Status | Q&A
Ask Your Question

rosdep doesn't "see" Python 3 package

asked 2020-10-16 22:40:25 -0500

jacki gravatar image

updated 2020-10-21 20:57:01 -0500

i'm installing cartography,when i executing the command

rosdep install --from-paths src --ignore-src --rosdistro=${ROS_DISTRO} -y

in https://google-cartographer-ros.readt... always turn to executing command

sudo -H apt-get install -y python-sphinx

however,i'm using python3 and the rosdep version in my ubuntu20.04LTS is python3-rosdep,why it will turn to install python-sphinx?i think the right sphinx version for this is python3-sphinx and i apt-get install it and it does be installed ,then it still reports the same error.therefore i am stuck in the above commands.

here are the errors:

Reading package lists... Done
Building dependency tree       
Reading state information... Done
Package python-sphinx is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source
However the following packages replace it:
  sphinx-doc sphinx-common

E: Package 'python-sphinx' has no installation candidate
ERROR: the following rosdeps failed to install
  apt: command [sudo -H apt-get install -y python-sphinx] failed
edit retag flag offensive close merge delete

2 Answers

Sort by » oldest newest most voted

answered 2020-10-21 17:19:05 -0500

tfoote gravatar image

rosdep will attempt to install whatever dependency is declared in the package.xml files for the packages that you are asking it to resolve.

In this case I believe that you're using a package that declares an explicit dependency on the rosdep key python-sphinx

You are either using the wrong branch for that package or it has not yet been updated to support a python3 version of the rosdep, python3-sphinx

If the package has not been updated yet a pull request to help the packages at issue migrate to be Python 3 compatible would I'm sure be appreciated. There's a guide here:

edit flag offensive delete link more


thanks for answering,i just install python3-sphinx by apt and ignore “rosdep install --from-paths src --ignore-src --rosdistro=${ROS_DISTRO} -y”,then i solve dependencies once i encountered while compling cartographer.

jacki gravatar image jacki  ( 2020-10-21 21:00:26 -0500 )edit

answered 2020-10-18 11:27:12 -0500

MrFermi gravatar image

I had this exact same problem. You have to install python-sphinx yourself from the ubuntu package repository The installation will fail at first because it doesn't have all the required dependencies, so you have to install all of those, and their dependencies, in the same way.

edit flag offensive delete link more


i solve it by ignoring it .

jacki gravatar image jacki  ( 2020-10-21 21:13:44 -0500 )edit

Your Answer

Please start posting anonymously - your entry will be published after you log in or create a new account.

Add Answer

Question Tools



Asked: 2020-10-16 22:40:25 -0500

Seen: 2,191 times

Last updated: Oct 21 '20