There is a new bug in Maya 2015, if you try to create an itemFilterAttr with some filters like hidden, writable, readable, keyable, etc. in conjunction of the -byScript flag. It crashes regardless of the programming language used. MEL, maya.cmds and pymel even with the example given in the its documentation.
def procName(nodeName, attrName):
return True
cmds.itemFilterAttr(keyable=True, byScript=procName)
global proc int procName(string $nodeName, string $attrName) {
return 1;
}
itemFilterAttr -k 1 -bs procName;
The filterClass attribute of the itemFilterAttr is set to 0 (other) by default on 2014 while it is set to 2 (user) in 2015.