python - 恢复模式下的 etree.XMLParser 是否仍会抛出解析错误？

Question

我有一个实用程序方法，它使用创建为 etree.XMLParser(recover=True) 的解析器来解析 XML。我想在单元测试中测试失败场景。除了空输入抛出 lxml.etree.XMLSyntaxError 之外，我似乎无法破坏解析器。

我的问题是:是否可以为该解析器构造一个 StringIO 或 BytesIO 输入，以便解析器抛出解析错误？

这是一些示例(使用 Python 3.5 和 lxml 4.3.3 测试):

from io import BytesIO
from lxml import etree


def parse(xml):
    parser = etree.XMLParser(recover=True)
    elem = etree.parse(BytesIO(xml), parser)
    print(etree.tostring(elem))


parse(b'<broken<')  # prints b'<broken/>'
parse(b'</lf|\jf>')  # prints None
parse('<?xml encoding="ascii"?><foo>æøå</foo>'.encode('utf-8'))  # prints b'<foo/>'
parse(b'')  # Throws lxml.etree.XMLSyntaxError

Answer 1

如果我在您显示的任何不引发错误的错误输入的开头添加了 NULL 字符，我确实会收到错误。例如:

parse(b'\0<broken<')

产生:

Traceback (most recent call last):
  File "test.py", line 13, in <module>
    parse(b'\0<broken<')  # prints b'<broken/>'
  File "test.py", line 9, in parse
    elem = etree.parse(BytesIO(xml), parser)
  File "src/lxml/etree.pyx", line 3435, in lxml.etree.parse
  File "src/lxml/parser.pxi", line 1857, in lxml.etree._parseDocument
  File "src/lxml/parser.pxi", line 1877, in lxml.etree._parseMemoryDocument
  File "src/lxml/parser.pxi", line 1765, in lxml.etree._parseDoc
  File "src/lxml/parser.pxi", line 1127, in lxml.etree._BaseParser._parseDoc
  File "src/lxml/parser.pxi", line 601, in lxml.etree._ParserContext._handleParseResultDoc
  File "src/lxml/parser.pxi", line 711, in lxml.etree._handleParseResult
  File "src/lxml/parser.pxi", line 640, in lxml.etree._raiseParseError
  File "<string>", line 1
lxml.etree.XMLSyntaxError: Document is empty, line 1, column 1