Fix LP #707927:

- Hardened XML import parsing against missing boolean attributes.
 
- Ensured that emitted XML export has a valid encoding, even when passed
  'None'.

Products/DCWorkflow/CHANGES.txt

@@ -4,7 +4,13 @@ Products.DCWorkflow Changelog
 2.3.0-alpha (unreleased)
 ------------------------
 
-- Fixed Chameleon compatibility in `state_groups.pt`.
+- Hardened XML import parsing against missing boolean attributes.
+  (https://bugs.launchpad.net/zope-cmf/+bug/707927)
+
+- Ensured that emitted XML export has a valid encoding, even when passed
+  'None'.  (https://bugs.launchpad.net/zope-cmf/+bug/707927)
+
+- Fixed Chameleon compatibility in 'state_groups.pt'.
 
 - Workflow states cannot be renamed through the ZMI.
   (https://bugs.launchpad.net/zope-cmf/+bug/625722)

Products/DCWorkflow/exportimport.py

@@ -678,7 +678,7 @@ def _extractStateNodes( root, encoding=None ):
         for p_map in s_node.getElementsByTagName( 'permission-map' ):
 
             name = _getNodeAttribute( p_map, 'name', encoding )
-            acquired = _getNodeAttributeBoolean( p_map, 'acquired' )
+            acquired = _queryNodeAttributeBoolean( p_map, 'acquired', False )
 
             roles = [ _coalesceTextNodeChildren( x, encoding )
                         for x in p_map.getElementsByTagName(
@@ -760,14 +760,17 @@ def _extractVariableNodes( root, encoding=None ):
         info = { 'variable_id' : _getNodeAttribute( v_node, 'variable_id'
                                                     , encoding )
                , 'description' : _extractDescriptionNode( v_node, encoding )
-               , 'for_catalog' : _getNodeAttributeBoolean( v_node
+               , 'for_catalog' : _queryNodeAttributeBoolean( v_node
                                                            , 'for_catalog'
+                                                           , False
                                                            )
-               , 'for_status' : _getNodeAttributeBoolean( v_node
+               , 'for_status' : _queryNodeAttributeBoolean( v_node
                                                           , 'for_status'
+                                                          , False
                                                           )
-               , 'update_always' : _getNodeAttributeBoolean( v_node
+               , 'update_always' : _queryNodeAttributeBoolean( v_node
                                                              , 'update_always'
+                                                             , False
                                                              )
                , 'default' : _extractDefaultNode( v_node, encoding )
                , 'guard' : _extractGuardNode( v_node, encoding )

Products/DCWorkflow/xml/wtcWorkflowExport.xml

-<?xml version="1.0"?>
+<?xml version="1.0" encoding="UTF-8"?>
 <dc-workflow
         xmlns:tal="http://xml.zope.org/namespaces/tal"
         workflow_id="dcworkflow"