R2021b python change - Unable to return the number of named arguments if not in an active function.

In Matlab R2021b, I have problems running my python code. This problem did not exist in R2021a.

I get an error

"Unable to return the number of named arguments if not in an active function. "

I have a class defeinition, with variables and functions, written in python. The actual class connects to an webservice api.

For example I tell matlab to run python, run the api.py file, and create the class object main(). Set the output of this to a variable.

>> pobj = py.api.main()

If I want to retrieve 'data' which is a class variable I use:

>> pobj.data

The above works fine in both R2021a and R2021b.

The problem is if I want to run a class function 'func'

>> pobj.func()

In R2021a this would work.

In R2021b I get the error

"Unable to return the number of named arguments if not in an active function."

Please assist me to find a solution.

[Sean Gillen]

I am not sure why this is happening but I am facing the same issue. I have found that not assigning my object to a matlab variable I was able to workl around this. See if you can run py.api.main().func() without error.

[Zouhair Mahboubi]

Having similar issue - this seems to have broken backward compatibility :s

[Rory Wheeler]

Thanks to all for feedback and assistance bringing the issue to Mathworks attention.

Answer 1

[Rory Wheeler]

The issue is now resolved. It was a bug and is fixed by updating to Matlab to "R2021b Update 1".

If interested read the bug report and fix here and R2021b Update 1 release notes here.