From 85b664e506d73780232c256b6dfbaf1f266cdabd Mon Sep 17 00:00:00 2001
From: Stefan Behnel <stefan_ml@behnel.de>
Date: Fri, 1 Jul 2022 21:06:10 +0200
Subject: [PATCH 1/3] Fix a crash when incorrect parser input occurs together
with usages of iterwalk() on trees generated by the same parser.
---
src/lxml/apihelpers.pxi | 7 ++++---
src/lxml/iterparse.pxi | 11 ++++++-----
src/lxml/tests/test_etree.py | 20 ++++++++++++++++++++
3 files changed, 30 insertions(+), 8 deletions(-)
diff --git a/src/lxml/apihelpers.pxi b/src/lxml/apihelpers.pxi
index 5eb3416..88a031d 100644
--- a/src/lxml/apihelpers.pxi
+++ b/src/lxml/apihelpers.pxi
@@ -246,9 +246,10 @@ cdef dict _build_nsmap(xmlNode* c_node):
while c_node is not NULL and c_node.type == tree.XML_ELEMENT_NODE:
c_ns = c_node.nsDef
while c_ns is not NULL:
- prefix = funicodeOrNone(c_ns.prefix)
- if prefix not in nsmap:
- nsmap[prefix] = funicodeOrNone(c_ns.href)
+ if c_ns.prefix or c_ns.href:
+ prefix = funicodeOrNone(c_ns.prefix)
+ if prefix not in nsmap:
+ nsmap[prefix] = funicodeOrNone(c_ns.href)
c_ns = c_ns.next
c_node = c_node.parent
return nsmap
diff --git a/src/lxml/iterparse.pxi b/src/lxml/iterparse.pxi
index 4c20506..3da7485 100644
--- a/src/lxml/iterparse.pxi
+++ b/src/lxml/iterparse.pxi
@@ -419,7 +419,7 @@ cdef int _countNsDefs(xmlNode* c_node):
count = 0
c_ns = c_node.nsDef
while c_ns is not NULL:
- count += 1
+ count += (c_ns.href is not NULL)
c_ns = c_ns.next
return count
@@ -430,9 +430,10 @@ cdef int _appendStartNsEvents(xmlNode* c_node, list event_list) except -1:
count = 0
c_ns = c_node.nsDef
while c_ns is not NULL:
- ns_tuple = (funicode(c_ns.prefix) if c_ns.prefix is not NULL else '',
- funicode(c_ns.href))
- event_list.append( (u"start-ns", ns_tuple) )
- count += 1
+ if c_ns.href:
+ ns_tuple = (funicodeOrEmpty(c_ns.prefix),
+ funicode(c_ns.href))
+ event_list.append( (u"start-ns", ns_tuple) )
+ count += 1
c_ns = c_ns.next
return count
diff --git a/src/lxml/tests/test_etree.py b/src/lxml/tests/test_etree.py
index ef5c54b..7b85596 100644
--- a/src/lxml/tests/test_etree.py
+++ b/src/lxml/tests/test_etree.py
@@ -1459,6 +1459,26 @@ class ETreeOnlyTestCase(HelperTestCase):
[1,2,1,4],
counts)
+ def test_walk_after_parse_failure(self):
+ # This used to be an issue because libxml2 can leak empty namespaces
+ # between failed parser runs. iterwalk() failed to handle such a tree.
+ try:
+ etree.XML('''<anot xmlns="1">''')
+ except etree.XMLSyntaxError:
+ pass
+ else:
+ assert False, "invalid input did not fail to parse"
+
+ et = etree.XML('''<root> </root>''')
+ try:
+ ns = next(etree.iterwalk(et, events=('start-ns',)))
+ except StopIteration:
+ # This would be the expected result, because there was no namespace
+ pass
+ else:
+ # This is a bug in libxml2
+ assert not ns, repr(ns)
+
def test_itertext_comment_pi(self):
# https://bugs.launchpad.net/lxml/+bug/1844674
XML = self.etree.XML
--
2.37.2
From c26503461af4c250fc6e771887fae7f9dd208e9b Mon Sep 17 00:00:00 2001
From: Stefan Behnel <stefan_ml@behnel.de>
Date: Fri, 1 Jul 2022 21:19:44 +0200
Subject: [PATCH 2/3] Prevent parse failure in new test from leaking into later
test runs.
---
src/lxml/tests/test_etree.py | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/src/lxml/tests/test_etree.py b/src/lxml/tests/test_etree.py
index 7b85596..8171e03 100644
--- a/src/lxml/tests/test_etree.py
+++ b/src/lxml/tests/test_etree.py
@@ -1462,14 +1462,16 @@ class ETreeOnlyTestCase(HelperTestCase):
def test_walk_after_parse_failure(self):
# This used to be an issue because libxml2 can leak empty namespaces
# between failed parser runs. iterwalk() failed to handle such a tree.
+ parser = etree.XMLParser()
+
try:
- etree.XML('''<anot xmlns="1">''')
+ etree.XML('''<anot xmlns="1">''', parser=parser)
except etree.XMLSyntaxError:
pass
else:
assert False, "invalid input did not fail to parse"
- et = etree.XML('''<root> </root>''')
+ et = etree.XML('''<root> </root>''', parser=parser)
try:
ns = next(etree.iterwalk(et, events=('start-ns',)))
except StopIteration:
--
2.37.2
From 2e37fbe5c54a188394aa066c3074ab974f6b9f61 Mon Sep 17 00:00:00 2001
From: Stefan Behnel <stefan_ml@behnel.de>
Date: Tue, 19 Jul 2022 08:25:20 +0200
Subject: [PATCH 3/3] Work around libxml2 bug in affected versions that failed
to reset the namespace count in the parser context.
See https://gitlab.gnome.org/GNOME/libxml2/-/issues/378
---
src/lxml/includes/xmlparser.pxd | 1 +
src/lxml/parser.pxi | 3 +++
src/lxml/tests/test_etree.py | 3 +--
3 files changed, 5 insertions(+), 2 deletions(-)
diff --git a/src/lxml/includes/xmlparser.pxd b/src/lxml/includes/xmlparser.pxd
index a196e34..45acfc8 100644
--- a/src/lxml/includes/xmlparser.pxd
+++ b/src/lxml/includes/xmlparser.pxd
@@ -144,6 +144,7 @@ cdef extern from "libxml/parser.h":
void* userData
int* spaceTab
int spaceMax
+ int nsNr
bint html
bint progressive
int inSubset
diff --git a/src/lxml/parser.pxi b/src/lxml/parser.pxi
index 35b5145..3187a38 100644
--- a/src/lxml/parser.pxi
+++ b/src/lxml/parser.pxi
@@ -569,6 +569,9 @@ cdef class _ParserContext(_ResolverContext):
self._c_ctxt.disableSAX = 0 # work around bug in libxml2
else:
xmlparser.xmlClearParserCtxt(self._c_ctxt)
+ # work around bug in libxml2 [2.9.10 .. 2.9.14]:
+ # https://gitlab.gnome.org/GNOME/libxml2/-/issues/378
+ self._c_ctxt.nsNr = 0
cdef int prepare(self, bint set_document_loader=True) except -1:
cdef int result
diff --git a/src/lxml/tests/test_etree.py b/src/lxml/tests/test_etree.py
index 8171e03..d767cfb 100644
--- a/src/lxml/tests/test_etree.py
+++ b/src/lxml/tests/test_etree.py
@@ -1478,8 +1478,7 @@ class ETreeOnlyTestCase(HelperTestCase):
# This would be the expected result, because there was no namespace
pass
else:
- # This is a bug in libxml2
- assert not ns, repr(ns)
+ assert False, "Found unexpected namespace '%s'" % ns
def test_itertext_comment_pi(self):
# https://bugs.launchpad.net/lxml/+bug/1844674
--
2.37.2