Validation unable to find DTD since 4.9.3 version

[François Ferry]

Hello,

I encounter an error when trying to parse a string using etree.fromstring since I'm using lxml==4.9.3 (I don't have the issue with lxml==4.9.2). You can find in attachment a small script allowing to reproduce it.

Here is the error:

Traceback (most recent call last):
  File "/home/fferry/src/interne/cubes/crm/dtd_error.py", line 14, in <module>
    etree.fromstring(XHTML, parser=etree.XMLParser(dtd_validation=True))
  File "src/lxml/etree.pyx", line 3257, in lxml.etree.fromstring
  File "src/lxml/parser.pxi", line 1916, in lxml.etree._parseMemoryDocument
  File "src/lxml/parser.pxi", line 1803, in lxml.etree._parseDoc
  File "src/lxml/parser.pxi", line 1144, in lxml.etree._BaseParser._parseDoc
  File "src/lxml/parser.pxi", line 618, in lxml.etree._ParserContext._handleParseResultDoc
  File "src/lxml/parser.pxi", line 728, in lxml.etree._handleParseResult
  File "src/lxml/parser.pxi", line 657, in lxml.etree._raiseParseError
  File "<string>", line 3
lxml.etree.XMLSyntaxError: Validation failed: no DTD found !, line 3, column 43

Here are my library versions:

Python : sys.version_info(major=3, minor=9, micro=2, releaselevel='final', serial=0)
lxml.etree : (4, 9, 3, 0)
libxml used : (2, 10, 3)
libxml compiled : (2, 10, 3)
libxslt used : (1, 1, 38)
libxslt compiled : (1, 1, 38)

Kind regards,
François.

[scoder (scoder)]

Probably a duplicate of ticket 2029411.