[lmi] xmlwrapp '-Wswitch-enum' warning [Was: xmlwrapp '-Wnull-dereference' warning]

[Greg Chicares]

On 2019-03-22 00:23, Greg Chicares wrote:
> Enabling '-Wnull-dereference' for lmi builds

Later, enabling '-Wswitch-enum' found:

/opt/lmi/third_party/src/libxml/node.cxx:518:12: error: enumeration value 
'XML_ATTRIBUTE_NODE' not handled in switch [-Werror=switch-enum]
/opt/lmi/third_party/src/libxml/node.cxx:518:12: error: enumeration value 
'XML_HTML_DOCUMENT_NODE' not handled in switch [-Werror=switch-enum]
/opt/lmi/third_party/src/libxml/node.cxx:518:12: error: enumeration value 
'XML_DOCB_DOCUMENT_NODE' not handled in switch [-Werror=switch-enum]

which, if desired, might be prevented thus:

         case XML_XINCLUDE_END:          return type_xinclude;
+        case XML_ATTRIBUTE_NODE:        // fall through
+        case XML_HTML_DOCUMENT_NODE:    // fall through
+        case XML_DOCB_DOCUMENT_NODE:    // fall through
         default:                        return type_element;

So many cases are listed explicitly that adding the few that aren't may
be a good idea. Optionally removing 'default:' (while preserving its code)
is a matter of style, which might be good if this is the only 'default:'
in the library, or not good if every other 'switch' has a 'default:'.

Whether or not this suggestion and the one in the preceding message are
adopted into xmlwrapp doesn't matter for lmi, whose makefiles will exempt
xmlwrapp from these warnings.