Compile Errors with lxml.etree + Python 3.10.0a0

[Cooper Lees]

Seems having multiple issues, but looks Cython related.

 building 'lxml.etree' extension
  creating build/temp.linux-x86_64-3.10
  creating build/temp.linux-x86_64-3.10/src
  creating build/temp.linux-x86_64-3.10/src/lxml
  gcc -pthread -Wno-unused-result -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall -g -fstack-protector --param=ssp-buffer-size=4 -Wformat -Werror=format-security -fPIC -DCYTHON_CLINE_IN_TRACEBACK=0 -I/usr/include/libxml2 -Isrc -Isrc/lxml/includes -I/home/travis/virtualenv/python3.10-dev/include -I/opt/python/3.10-dev/include/python3.10 -c src/lxml/etree.c -o build/temp.linux-x86_64-3.10/src/lxml/etree.o -w
  src/lxml/etree.c: In function ‘__Pyx_PyList_Append’:
  src/lxml/etree.c:5705:23: error: lvalue required as left operand of assignment
           Py_SIZE(list) = len+1;
                         ^
  src/lxml/etree.c: In function ‘__Pyx_ListComp_Append’:
  src/lxml/etree.c:5837:23: error: lvalue required as left operand of assignment
           Py_SIZE(list) = len+1;
                         ^
  src/lxml/etree.c: In function ‘__pyx_tp_dealloc_4lxml_5etree__LogEntry’:
  src/lxml/etree.c:225191:5: error: lvalue required as increment operand
       ++Py_REFCNT(o);
       ^
  src/lxml/etree.c:225193:5: error: lvalue required as decrement operand
       --Py_REFCNT(o);
       ^
  src/lxml/etree.c: In function ‘__pyx_tp_dealloc_4lxml_5etree__Document’:
  src/lxml/etree.c:226254:5: error: lvalue required as increment operand
       ++Py_REFCNT(o);
       ^
  src/lxml/etree.c:226256:5: error: lvalue required as decrement operand
       --Py_REFCNT(o);
       ^
  src/lxml/etree.c: In function ‘__pyx_tp_dealloc_4lxml_5etree__Element’:
  src/lxml/etree.c:226587:5: error: lvalue required as increment operand
       ++Py_REFCNT(o);
       ^
  src/lxml/etree.c:226589:5: error: lvalue required as decrement operand
       --Py_REFCNT(o);
       ^
  src/lxml/etree.c: In function ‘__pyx_tp_dealloc_4lxml_5etree__MultiTagMatcher’:
  src/lxml/etree.c:228274:5: error: lvalue required as increment operand
       ++Py_REFCNT(o);
       ^
  src/lxml/etree.c:228276:5: error: lvalue required as decrement operand
       --Py_REFCNT(o);
       ^
  src/lxml/etree.c: In function ‘__pyx_tp_dealloc_4lxml_5etree__ParserDictionaryContext’:
  src/lxml/etree.c:232830:5: error: lvalue required as increment operand
       ++Py_REFCNT(o);
       ^
  src/lxml/etree.c:232832:5: error: lvalue required as decrement operand
       --Py_REFCNT(o);
       ^
  src/lxml/etree.c: In function ‘__pyx_tp_dealloc_4lxml_5etree__ParserContext’:
  src/lxml/etree.c:233095:5: error: lvalue required as increment operand
       ++Py_REFCNT(o);
       ^
  src/lxml/etree.c:233097:5: error: lvalue required as decrement operand
       --Py_REFCNT(o);
       ^
  src/lxml/etree.c: In function ‘__pyx_tp_dealloc_4lxml_5etree__IncrementalFileWriter’:
  src/lxml/etree.c:235299:5: error: lvalue required as increment operand
       ++Py_REFCNT(o);
       ^
  src/lxml/etree.c:235301:5: error: lvalue required as decrement operand
       --Py_REFCNT(o);
       ^
  src/lxml/etree.c: In function ‘__pyx_tp_dealloc_4lxml_5etree__XPathEvaluatorBase’:
  src/lxml/etree.c:237626:5: error: lvalue required as increment operand
       ++Py_REFCNT(o);
       ^
  src/lxml/etree.c:237628:5: error: lvalue required as decrement operand
       --Py_REFCNT(o);
       ^
  src/lxml/etree.c: In function ‘__pyx_tp_dealloc_4lxml_5etree_XPath’:
  src/lxml/etree.c:237963:5: error: lvalue required as increment operand
       ++Py_REFCNT(o);
       ^
  src/lxml/etree.c:237965:5: error: lvalue required as decrement operand
       --Py_REFCNT(o);
       ^
  src/lxml/etree.c: In function ‘__pyx_tp_dealloc_4lxml_5etree_XSLTAccessControl’:
  src/lxml/etree.c:238595:5: error: lvalue required as increment operand
       ++Py_REFCNT(o);
       ^
  src/lxml/etree.c:238597:5: error: lvalue required as decrement operand
       --Py_REFCNT(o);
       ^
  src/lxml/etree.c: In function ‘__pyx_tp_dealloc_4lxml_5etree_XSLT’:
  src/lxml/etree.c:238944:5: error: lvalue required as increment operand
       ++Py_REFCNT(o);
       ^
  src/lxml/etree.c:238946:5: error: lvalue required as decrement operand
       --Py_REFCNT(o);
       ^
  src/lxml/etree.c: In function ‘__pyx_tp_dealloc_4lxml_5etree_DTD’:
  src/lxml/etree.c:240466:5: error: lvalue required as increment operand
       ++Py_REFCNT(o);
       ^
  src/lxml/etree.c:240468:5: error: lvalue required as decrement operand
       --Py_REFCNT(o);
       ^
  src/lxml/etree.c: In function ‘__pyx_tp_dealloc_4lxml_5etree_RelaxNG’:
  src/lxml/etree.c:240832:5: error: lvalue required as increment operand
       ++Py_REFCNT(o);
       ^
  src/lxml/etree.c:240834:5: error: lvalue required as decrement operand
       --Py_REFCNT(o);
       ^
  src/lxml/etree.c: In function ‘__pyx_tp_dealloc_4lxml_5etree_XMLSchema’:
  src/lxml/etree.c:241178:5: error: lvalue required as increment operand
       ++Py_REFCNT(o);
       ^
  src/lxml/etree.c:241180:5: error: lvalue required as decrement operand
       --Py_REFCNT(o);
       ^
  src/lxml/etree.c: In function ‘__pyx_tp_dealloc_4lxml_5etree__ParserSchemaValidationContext’:
  src/lxml/etree.c:241300:5: error: lvalue required as increment operand
       ++Py_REFCNT(o);
       ^
  src/lxml/etree.c:241302:5: error: lvalue required as decrement operand
       --Py_REFCNT(o);
       ^
  src/lxml/etree.c: In function ‘__pyx_tp_dealloc_4lxml_5etree_Schematron’:
  src/lxml/etree.c:241658:5: error: lvalue required as increment operand
       ++Py_REFCNT(o);
       ^
  src/lxml/etree.c:241660:5: error: lvalue required as decrement operand
       --Py_REFCNT(o);
       ^
  src/lxml/etree.c: In function ‘__Pyx_PyList_Pop’:
  src/lxml/etree.c:262113:20: error: lvalue required as left operand of assignment
           Py_SIZE(L) -= 1;
                      ^
  Compile failed: command '/usr/bin/gcc' failed with exit code 1
  creating tmp
  cc -I/usr/include/libxml2 -I/usr/include/libxml2 -c /tmp/xmlXPathInitc643yela.c -o tmp/xmlXPathInitc643yela.o
  cc tmp/xmlXPathInitc643yela.o -lxml2 -o a.out
  error: command '/usr/bin/gcc' failed with exit code 1

Example build error: https://travis-ci.org/github/pypa/bandersnatch/jobs/694378588

[scoder (scoder)]

Thanks, yes, it just needs a rebuild with Cython 0.29.20, as soon as that is released.