“There is a memory leak indeed, I think I identified it coming from the initXPathParserDict function (in parser.pxi). The (libxml) reference count of pctxt.dict is a bit difficult to follow, but when I added a xmlparser.xmlDictFree(pctxt.dict) the memory leak disappeared.”

Thanks – at least it confirms it. I was playing with Heapy to find a memory leak and it suggested something in parser.pxi but that’s as far as I got. Are you a maintainer of lxml and can look at this? Or should I file a bug report.

Thanks