lxml.etree & StringIO strangeness

lxml-tests.py

import StringIO, lxml.etree

xmldata="<root>data</root>"
buffer=StringIO.StringIO(xmldata)
for event, element in lxml.etree.iterparse(buffer):
        print "%s %s %s" % (event, element.tag, element.text)
buffer.close()

buffer=StringIO.StringIO()
buffer.write(xmldata)
buffer.seek(0) # YAY! thanks nosklo (#python@freenode)
for event, element in lxml.etree.iterparse(buffer):
        print "%s %s %s" % (event, element.tag, element.text)
buffer.close()

By filling on the second part the StringIO via .write() makes lxml.etree.iterparse throw an execption, why ?

Traceback (most recent call last):
  File "lxml-1.py", line 10, in 
    for event, element in lxml.etree.iterparse(buffer):
  File "iterparse.pxi", line 515, in lxml.etree.iterparse.__next__ (src/lxml/lxml.etree.c:87076)
  File "parser.pxi", line 565, in lxml.etree._raiseParseError (src/lxml/lxml.etree.c:64521)
lxml.etree.XMLSyntaxError: Extra content at the end of the document, line 1, column 1

your second code doesn't seek back to beginning. Use .seek(0)