Dirty fix for error '_object_has_no_attribute_'getSlave' in EtherCAT extension

traceback:
File "/home/developer/WorkData/PLC/beremiz/beremiz/IDEFrame.py", line 1433, in OnPouSelectedChanged
window.RefreshView()
File "/home/developer/WorkData/PLC/beremiz/beremiz/etherlab/ConfigEditor.py", line 837, in RefreshView
self.RefreshProcessVariables()
File "/home/developer/WorkData/PLC/beremiz/beremiz/etherlab/ConfigEditor.py", line 886, in RefreshProcessVariables
slaves = self.Controler.GetSlaves(**self.CurrentNodesFilter)
File "/home/developer/WorkData/PLC/beremiz/beremiz/etherlab/EthercatMaster.py", line 341, in GetSlaves
for slave in self.Config.getConfig().getSlave():
<type 'exceptions.AttributeError'>:_'lxml.etree._Element'_object_has_no_attribute_'getSlave'

Steps to reproduce problem:

- Add new EtherCAT master
- Add new EthercatNode to the master
- double click on


this is looks like dirty hack to fix strange problem with initial[0]
changing its type after returning from _init_ method to lxml.etree._Element
As a result all methods generated by class factory are lost.

For example, in function initMethod initial[0].__class__ points to
xmlclass.xmlclass.Config. After map(self.append, initial)
self.Config.__class__ is 'xmlclass.xmlclass.Config' as well.
But after returning from initMethod (_init) in CreateElement
self.Config.__class__ has changed to lxml.etree._Element.


I've noticed similar behavior if copy/deepcopy is used for any child
of etree.ElementBase. See simple example below.
[-------------------------------------------------------------]
#!/usr/bin/python

from __future__ import print_function
from lxml import etree
import copy

class DefaultElementClass(etree.ElementBase):
def getLocalTag(self):
return etree.QName(self.tag).localname


def printInformation(x):
print(x, x.__class__, "getLocalTag" in dir(x))


a = DefaultElementClass()
printInformation(a)

#
printInformation(copy.copy(a))
printInformation(copy.deepcopy(a))
[-------------------------------------------------------------]

     1

<?xml version='1.0' encoding='utf-8'?>

     2

<PyFile xmlns:xhtml="http://www.w3.org/1999/xhtml" xmlns:xsd="http://www.w3.org/2001/XMLSchema">

     3

  <variables>

     4

    <variable name="SomeVarName" type="DINT"/>

     5

    <variable name="Grumpf" type="STRING"/>

     6

  </variables>

     7

  <globals>

     8

    <xhtml:p><![CDATA[

     9

print "All python PLC globals variables :", PLCGlobalsDesc

    10

print "Current extention name :", __ext_name__

    11

]]></xhtml:p>

    12

  </globals>

    13

  <init>

    14

    <xhtml:p><![CDATA[

    15

]]></xhtml:p>

    16

  </init>

    17

  <cleanup>

    18

    <xhtml:p><![CDATA[

    19

]]></xhtml:p>

    20

  </cleanup>

    21

  <start>

    22

    <xhtml:p><![CDATA[

    23

]]></xhtml:p>

    24

  </start>

    25

  <stop>

    26

    <xhtml:p><![CDATA[

    27

]]></xhtml:p>

    28

  </stop>

    29

</PyFile>