Simulation loops infinitely with python processes

[juan-g-bonilla]

Describe the bug
A SimBaseClass will freeze (loop infinitely) when including a simulationArchTypes.PythonProcessClass with priority higher than other C/C++ processes in the sim.

To reproduce

from Basilisk.utilities import SimulationBaseClass
from Basilisk.utilities import macros

def test(freeze):

    scSim = SimulationBaseClass.SimBaseClass()

    dynProcess = scSim.CreateNewProcess("simProcess", 10)
    dynProcess.addTask(scSim.CreateNewTask("sensorTask", macros.sec2nano(10.)))

    # Note that having a python priority > C/C++ priority
    # causes a freeze, but not the other way around
    pyProcess = scSim.CreateNewPythonProcess("python", 11 if freeze else 9)

    scSim.InitializeSimulation()
    scSim.ConfigureStopTime(macros.sec2nano(30))
    scSim.ExecuteSimulation()

    print(f"Finished running (Was supposed to freeze? {freeze})")

if __name__ == '__main__':
    test(False)
    test(True) # You are going to have to kill it

Expected behavior
Either not freezing, or a clear error message when trying to create python processes with higher priority than C++ processes.

Desktop:

• OS: Windows 64bit
• Version 2.1.7b0 (built with develop when the latest commit was 4f6c57d at February 22nd, 2023 5:17 PM)
• Python version: Python 3.11.0

Additional context
I would suggest adding an error message for the time being (as you are not supposed to use python processes with higher priority than C/C++ anyway, and this would make it very clear) until #200 gets implemented.

[joaogvcarneiro]

Thanks for pointing this out, @juan-g-bonilla. The last time I worked with Python processes, the simulation didn't freeze. Rather, it simply ignored my priority setting and ran the Python process at the end.

Thanks for mentioning issue #200. This might be a higher priority than I had initially considered.