DAG Drawer not working

[dennis-liu-1]

Information

• Qiskit Terra version: 0.10.0
• Python version: 3.7.3
• Operating system: Mac

What is the current behavior?

Calling dag_drawer() in the tutorial 4_transpiler_passes_and_passmanager.ipynb on IQX yields the following error:

Steps to reproduce the problem

Ran other code that calls dag_drawer() as well, and this results in the same error.

What is the expected behavior?

Draw the dag without errors

Suggested solutions

[mtreinish]

It's caused because of an incompatibility with networkx 2.4 and nxpd which is used to generate the visualizations. There are 2 fixes in progress for it, one in the upstream nxpd lib: chebee7i/nxpd#15 and the other in terra itself (which is to stop using nxpd): #3280 (this is blocked on test failures on python 3.5 with networkx 2.4, likely caused by assumed dict ordering)

In the meantime the only way to avoid this is to downgrade networkx to 2.3.0 (which is what we do for ci and test envs).