execute a notebook without a file extension, the notebook_name will lose the last character

[swg-liuge]

When executing a notebook without a file extension, the notebook file name will lose the last character, is that a bug?

CMD: jupyter nbconvert --to notebook --execute test

the test is a notebook file without file extension, generated a converted file which is named tes_convert.ipynb. and I checked the code, it is caused by this line of code：

I wonder if it does not support notebook files without suffixes?