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))
[-------------------------------------------------------------]

<?xml version='1.0' encoding='utf-8'?>
<CFile xmlns:xhtml="http://www.w3.org/1999/xhtml">
  <includes>
    <xhtml:p><![CDATA[
]]></xhtml:p>
  </includes>
  <variables>
    <variable name="TestInput" type="SINT" initial="0"/>
    <variable name="TestOutput" type="SINT"/>
  </variables>
  <globals>
    <xhtml:p><![CDATA[
volatile long Lock=0;
volatile char PtoC=1,CtoP=2;

extern long AtomicCompareExchange(long*,long, long);
extern char *PLC_ID;

int Simple_C_Call(int val){
  return val+1;
}

int Python_to_C_Call(char toC, char *fromC){
  /* Code called by python should never touch to 
     variables modified by PLC thread directly

     AtomicCompareExchange comes from 
     beremiz' runtime implementation */

  int res = 0;
  if(!AtomicCompareExchange((long*)&Lock, 0, 1)){
    PtoC=toC;
    *fromC=CtoP;
    AtomicCompareExchange((long*)&Lock, 1, 0);
    res=1;
  }
  printf("C code called by Python: toC %d fromC %d\n",toC,*fromC);
  printf("PLC_ID id %s\n",PLC_ID);
  return res;
}

int PLC_C_Call(char fromPLC, char *toPLC){
  /* PLC also have to be realy carefull not to 
     conflict with asynchronous python access */
  if(!AtomicCompareExchange((long*)&Lock, 0, 1)){
      CtoP = fromPLC;
      *toPLC = PtoC;
      AtomicCompareExchange((long*)&Lock, 1, 0);
      return 1;
  }
  return 0;
}
]]></xhtml:p>
  </globals>
  <initFunction>
    <xhtml:p><![CDATA[
]]></xhtml:p>
  </initFunction>
  <cleanUpFunction>
    <xhtml:p><![CDATA[
]]></xhtml:p>
  </cleanUpFunction>
  <retrieveFunction>
    <xhtml:p><![CDATA[
]]></xhtml:p>
  </retrieveFunction>
  <publishFunction>
    <xhtml:p><![CDATA[
if(!AtomicCompareExchange((long*)&Lock, 0, 1)){
    TestInput = CtoP + PtoC + TestOutput;
    AtomicCompareExchange((long*)&Lock, 1, 0);
}
]]></xhtml:p>
  </publishFunction>
</CFile>