None dereference error when only one motor is connected

[drigz]

Connect only one motor to the brick and try to send a program to drive a short distance.

robot@ev3dev:~$ python NEPOprog.py 
Exception AttributeError: "'LargeMotor' object has no attribute '_path'" in <bound method LargeMotor.__del__ of <ev3dev.core.LargeMotor object at 0xb65f7d50>> ignored
Traceback (most recent call last):
  File "NEPOprog.py", line 44, in <module>
    main()
  File "NEPOprog.py", line 33, in main
    run()
  File "NEPOprog.py", line 29, in run
    hal.driveDistance('C', 'B', False, 'foreward', 30, 20)
  File "/usr/lib/python2.7/dist-packages/roberta/ev3.py", line 353, in driveDistance
    ml.run_to_rel_pos(speed_regulation_enabled='on',
AttributeError: 'NoneType' object has no attribute 'run_to_rel_pos'

NEPOprog.py:

#!/usr/bin/python

from __future__ import absolute_import
from roberta.ev3 import Hal
from roberta.BlocklyMethods import BlocklyMethods
from sets import Set
from ev3dev import ev3 as ev3dev
import math

TRUE = True
_brickConfiguration = {
    'wheel-diameter': 5.6,
    'track-width': 18.0,
    'actors': {
        'B':Hal.makeLargeMotor(ev3dev.OUTPUT_B, 'on', 'foreward', 'right'),
        'C':Hal.makeLargeMotor(ev3dev.OUTPUT_C, 'on', 'foreward', 'left'),
    },
    'sensors': {
        '1':Hal.makeTouchSensor(ev3dev.INPUT_1),
        '2':Hal.makeGyroSensor(ev3dev.INPUT_2),
        '3':Hal.makeColorSensor(ev3dev.INPUT_3),
        '4':Hal.makeUltrasonicSensor(ev3dev.INPUT_4),
    },
}
_usedSensors = Set([])
hal = Hal(_brickConfiguration, _usedSensors)

def run():
    hal.driveDistance('C', 'B', False, 'foreward', 30, 20)

def main():
    try:
        run()
    except Exception as e:
        hal.drawText('Fehler im EV3', 0, 0)
        hal.drawText(e.__class__.__name__, 0, 1)
        if e.message:
            hal.drawText(e.message, 0, 2)
        hal.drawText('Press any key', 0, 4)
        while not hal.isKeyPressed('any'): hal.waitFor(500)
        raise

if __name__ == "__main__":
    main()

[ensonic]

The issue is that we create brickconfiguration entries for also unused elements. Right now the factory methods there are non-fatal, that is in case of error they return None.
We want to only create the brickconfiguration for used elements and then fail if we can't create all of them.
In OpenRoberta/robertalab@d771049684fa6c3d8e4e3e4da9df3f3bfbd70607 I am unly instantiating sensors that are used.

• also need to constrain this to actors
• make actor / sensor instantiation failures fatal again

The plan is to rename
https://github.com/OpenRoberta/robertalab/blob/HEAD/OpenRobertaRobot/src/main/java/de/fhg/iais/roberta/syntax/hardwarecheck/ev3/UsedSensorsCheckVisitor.java
to UsedHardwareCheckVisitor.java, track other resources too and add a getter for usedActors.

[ensonic]

The refactoring of the server code is done.