I am trying to pass a UTF-32 encoded string (with the XML encoding declaration) to lxml.etree. fromstring This raises an lxml.etree. XMLSyntaxError exception (Document is empty).

Is this expected? Following the same process for all other encodings that I have tested works fine (UTF-8, UTF-16, ASCII, ISO-8859-1, ISO-8859-2, BIG5, EUC-JP).

I have not tested this in libxml2 as I do not know how to.

Python : sys.version_ info(major= 3, minor=6, micro=0, releaselevel= 'final' , serial=0)
lxml.etree : (3, 8, 0, 0)
libxml used : (2, 9, 4)
libxml compiled : (2, 9, 4)
libxslt used : (1, 1, 29)
libxslt compiled : (1, 1, 29)

from lxml import etree
foo = """<?xml version='1.0' encoding= 'utf-32' ?>\n<tag attrib= '123'>< /tag>"" "
etree.fromstrin g(foo.encode( 'utf-32' ))
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "src/lxml/ lxml.etree. pyx", line 3228, in lxml.etree. fromstring (src/lxml/ lxml.etree. c:79594)
  File "src/lxml/ parser. pxi", line 1848, in lxml.etree. _parseMemoryDoc ument (src/lxml/ lxml.etree. c:119113)
  File "src/lxml/ parser. pxi", line 1736, in lxml.etree. _parseDoc (src/lxml/ lxml.etree. c:117793)
  File "src/lxml/ parser. pxi", line 1102, in lxml.etree. _BaseParser. _parseDoc (src/lxml/ lxml.etree. c:112037)
  File "src/lxml/ parser. pxi", line 595, in lxml.etree. _ParserContext. _handleParseRes ultDoc (src/lxml/ lxml.etree. c:105881)
  File "src/lxml/ parser. pxi", line 706, in lxml.etree. _handleParseRes ult (src/lxml/ lxml.etree. c:107589)
  File "src/lxml/ parser. pxi", line 635, in lxml.etree. _raiseParseErro r (src/lxml/ lxml.etree. c:106443)
  File "<string>", line 1
lxml.etree. XMLSyntaxError: Document is empty, line 1, column 1