Intel Core i7-5820k 4.1GHz
2x Nvidia GTX 970
Broken: 2.79 5bd8ac9
Short description of error
If you change the name of a Node Socket (not the socket's identifier) of a Cycles Shader Node during execution of a python script, Cycles will render the Material black.
Exact steps for others to reproduce the error
Download the blend file below:
Run the code in the text editor.
Switch to viewport preview.
To fix the problem, simply reset the two nodes, or add a new Material Output Node and a new Principled Node to the Node Tree. Connect the new nodes together and delete the old ones.