[lmi] xmlwrapp '-Wconversion' warnings [Was: xmlwrapp '-Wnull-dereference' warning]

[Greg Chicares]

On 2019-03-22 00:23, Greg Chicares wrote:
> Enabling '-Wnull-dereference' for lmi builds

Later, building with a x86_64-w64-mingw32 toolchain, I saw:

x86_64-w64-mingw32-g++ -c -I /opt/lmi/src/lmi -I /opt/lmi/third_party/include 
-I /opt/lmi/third_party/src -I /opt/lmi/local/include -I 
/opt/lmi/local/include/libxml2 -DLIBXML_USE_DLL -std=c++17 -Werror -Wconversion 
/opt/lmi/src/lmi/xml_xslt_wrapp.cpp -oxml_xslt_wrapp.o 2>&1 |less -S

In file included from /opt/lmi/src/lmi/xml_xslt_wrapp.cpp:31:
/opt/lmi/third_party/src/libxml/event_parser.cxx: In member function 'bool 
xml::event_parser::parse
_chunk(const char*, xml::event_parser::size_type)':
/opt/lmi/third_party/src/libxml/event_parser.cxx:403:51: error: conversion from 
'xml::event_parser::size_type' {aka 'long long unsigned int'} to 'int' may 
change value [-Werror=conversion]
     xmlParseChunk(pimpl_->parser_context_, chunk, length, 0);
                                                   ^~~~~~
In file included from /opt/lmi/src/lmi/xml_xslt_wrapp.cpp:33:
/opt/lmi/third_party/src/libxml/node.cxx: In constructor 
'xml::node::node(xml::node::cdata)':
/opt/lmi/third_party/src/libxml/node.cxx:324:109: error: conversion from 
'size_t' {aka 'long long unsigned int'} to 'int' may change value 
[-Werror=conversion]
     if ( (pimpl_->xmlnode_ = xmlNewCDataBlock(0, reinterpret_cast<const 
xmlChar*>(cdata_info.t), std::strlen(cdata_info.t))) == 0)
                                                                                
                  ~~~~~~~~~~~^~~~~~~~~~~~~~
In file included from /opt/lmi/src/lmi/xml_xslt_wrapp.cpp:39:
/opt/lmi/third_party/src/libxml/tree_parser.cxx: In member function 'void 
xml::tree_parser::init(const char*, xml::tree_parser::size_type, 
xml::error_handler*)':
/opt/lmi/third_party/src/libxml/tree_parser.cxx:202:50: error: conversion from 
'xml::tree_parser::size_type' {aka 'long long unsigned int'} to 'int' may 
change value [-Werror=conversion]
     if ( (ctxt = xmlCreateMemoryParserCtxt(data, size)) == 0)
                                                  ^~~~