bug#59537: `libxml-parse-xml-region` strips out the namespace information, and namespace prefix in the DOM representation

[Ramesh Nedunchezian]

On 24/11/22 15:52, Eli Zaretskii wrote:
>> Date: Thu, 24 Nov 2022 14:31:52 +0530
>> From: Ramesh Nedunchezian <rameshnedunchezian@outlook.com>
>>
>> `libxml-parse-xml-region` strips out the namespace information, and 
>> namespace prefix in the DOM representation.
>>
>> Stripping out the NAMESPACE information is a bug.
> AFAICT, we just call a function from libxml2.  So I guess the bug is in that
> library?

Do I need to upgrade? 

I am on a  Debian Unstable, and my laptop was updated only 3-months ago.  I 
would think that for all practical purposes, my libraries are "recent".

I am not familiar with XML or XML libraries much. 

May be Emacs should provide other entry points to libxml which would  preserve 
(or return) the namespace information ..

The problem with current state of affairs is that round tripping wouldn't work. 
 That is if I move from XML1->DOM->XML2, XML1 and XML2 will no longer be the 
same.

I believe, libxml was introduced to cater to Eww's HTML rendering.  So, would 
it be "reasonable" to say that the current entry point is sufficient to work 
with HTML-like XML, and not for ANY XML.


I am on debian unstable


$ uname -a

Linux debian 5.19.0-1-amd64 #1 SMP PREEMPT_DYNAMIC Debian 5.19.6-1 (2022-09-01) 
x86_64 GNU/Linux

~$ ldd `which emacs` | grep xml

    libxml2.so.2 => /lib/x86_64-linux-gnu/libxml2.so.2 (0x00007f5a62052000)


~$ ls -al /lib/x86_64-linux-gnu/libxml2.so.2
lrwxrwxrwx 1 root root 17 Jul 24 01:33 /lib/x86_64-linux-gnu/libxml2.so.2 -> 
libxml2.so.2.9.14

~$ dpkg -S libxml2.so.2.9.14

libxml2:amd64: /usr/lib/x86_64-linux-gnu/libxml2.so.2.9.14

~$ apt show libxml2:amd64

Package: libxml2
Version: 2.9.14+dfsg-1+b1
Priority: optional
Section: libs
Source: libxml2 (2.9.14+dfsg-1)
Maintainer: Debian XML/SGML Group <debian-xml-sgml-pkgs@lists.alioth.debian.org>
Installed-Size: 1,938 kB
Depends: libc6 (>= 2.33), libicu71 (>= 71.1-1~), liblzma5 (>= 
5.1.1alpha+20120614), zlib1g (>= 1:1.2.3.3)
Conflicts: w3c-dtd-xhtml
Homepage: http://xmlsoft.org
Tag: role::shared-lib
Download-Size: 708 kB
APT-Manual-Installed: no
APT-Sources: https://deb.debian.org/debian unstable/main amd64 Packages
Description: GNOME XML library
 XML is a metalanguage to let you design your own markup language.
 A regular markup language defines a way to describe information in
 a certain class of documents (eg HTML). XML lets you define your
 own customized markup languages for many classes of document. It
 can do this because it's written in SGML, the international standard
 metalanguage for markup languages.
 .
 This package provides a library providing an extensive API to handle
 such XML data files.