pyserial errorhandling in plotter.py tries to iterate over wrong Exception attribute

[seahawk1986]

When opening the serial connection using pyserial 3.x in plotter.py fails ( https://bazaar.launchpad.net/~inkscape.dev/inkscape/trunk/view/head:/share/extensions/plotter.py#L196 ), the script looks at the wrong element of the exception (which results in raising another Exception like in this post: https://forum.ubuntuusers.de/post/8682508/ ):

Traceback (most recent call last):
  File "plotter.py", line 227, in <module>
    e.affect()
  File "/usr/share/inkscape/extensions/inkex.py", line 268, in affect
    self.effect()
  File "plotter.py", line 96, in effect
    self.sendHpglToSerial()
  File "plotter.py", line 162, in sendHpglToSerial
    if 'ould not open port' in inst.args[0]:
TypeError: argument of type 'int' is not iterable

Minimal example in the python interpreter (somehow launchpad ignores the spaces before the commands in the lines after try and except when displaying the text):
>>> import serial
>>> mySerial = serial.Serial()
>>> mySerial.port = '/dev/ttyS0'
>>> try:
... mySerial.open()
... except Exception as inst:
... inst.args
... inst.args[0]
... inst.strerror
...
(13, "could not open port /dev/ttyS0: [Errno 13] Keine Berechtigung: '/dev/ttyS0'")
13
"could not open port /dev/ttyS0: [Errno 13] Keine Berechtigung: '/dev/ttyS0'"

It should be more reliable to use the inst.strerror Attribute of the Exception or str(inst) instead of an index-Based value in the Exception.

[jazzynico (jazzynico)]

Thanks for taking the time to file a report!

Bug reproduced on Xubuntu 16.04, Inkscape 0.91 and lp:inkscape/0.92.x rev.15315.

[jazzynico (jazzynico)]

Patch committed in lp:inkscape rev. 15413.
Proposing to backport to 0.92.1.

[Bryce Harrington (bryce)]

+1 for backport to 0.92.1.

Thanks jazzynico for the fix, and seahawk1986 for the analysis.

[jazzynico (jazzynico)]

Fixed in lp:inkscape/0.92.x rev. 15316.