Getting error that the owl "must be an rdflib term"

[shola-lawal]

Hi,

I am getting a must be an rdflib term errors. An example of the error message looks like this, "Subject http://www.inf.ufrgs.br/phi-group/ontologies/cora.owl#Robot-1 must be an rdflib term". It doesn't seem that the errors are due to the skiros.owl and skirosExtra.owl files but rather from the owl files in the IEEE-1872-2015 folder. However, this doesn't make sense because I am able to view the owl files from the IEEE-1872-2015 folder in Protégé 5.6.3.

I have attached to outputs below.

Please also note that there are _SyntaxWarning: "is" with a literal. Did you mean "=="?_ errors but this is related to python 3.8 raising a SyntaxWarning due to the usage of "is" instead of "==".

Environment:
Ubuntu 20.04.6
Python 3.8.10
ROS Noetic
rdflib 7.0.0

Please advise.
Thank you.

[matthias-mayr]

Thank you very much for reporting this.

The Syntax warning seems easy to fix. Interestingly enough, I haven't seen it with my noetic setups. I should take a look at the python versions those use.

For the rdflib-error, can you attach the turtle file of your scene? Here in the user interface is a Save Scene button. That would help to debug it.

[shola-lawal]

Hi @matthias-mayr,

Here is the turtle sim scene:

(Terminal 1)
$ roscore

(Terminal 2)
$ roslaunch skiros2_examples turtlesim_example.launch

I just added an empty scene after running the skiros2.

Below is the image:

[matthias-mayr]

Thanks for the instructions. It looks like RDFlib in version 7.0.0 introduced some breaking changes. Until this is resolved, you can switch to the previous version with

pip3 install rdflib==6.3.2

[TimKnissel]

Thank you for the update! With the version rdflib=6.3.2 it works for me.

[shola-lawal]

Amazing, thank you it works now!!

[matthias-mayr]

Thanks for the feedback.

I am reopening this issue, because it's only a fix and currently not even enforced by the installation procedure.

[matthias-mayr]

Chances are that #90 fixes this.

Please also note that there are SyntaxWarning: "is" with a literal. Did you mean "=="? errors but this is related to python 3.8 raising a SyntaxWarning due to the usage of "is" instead of "==".

Thanks for bringing up the warning. It is fixed now in 8b11b9e.

[marcusklang]

Merged in ros2-develop and seems fixed, recreate issue if not fixed.