Revisit libxml 2.9.13 compatibility

[voxik]

This is related to upstream discussion [1] which was triggered by my report in Fedora [2] (and of course also related to #2461). The issue is that on Fedora, we use system version of libxml for Nokogiri and we don't have the option to revert the behavior (unless reverting this for whole system which would probably not make a sense and would be against upstream) and if upstream insist that the new "breaking" behavior is the right one, I wonder what Nokogiri is going to do about it?

[voxik]

Actually now I noticed the upstream ticket was opened much earlier, my bad 😊 Nevertheless, the point stays.

[voxik]

There is actually this proposed patch in libxml2:

https://gitlab.gnome.org/GNOME/libxml2/-/commit/4fd69f3e27e4ef2f8fafa091e723497017c40646

While this patch fixes ActionView test failures, it keeps the rails-html-sanitizer test suite broken, but differently

[voxik]

This is example of the rails-html-sanitizer failure with the patch above:

Failure:
SanitizersTest#test_strip_unclosed_cdata [/builddir/build/BUILD/rails-html-sanitizer-1.4.2/usr/share/gems/gems/rails-html-sanitizer-1.4.2/test/sanitizer_test.rb:86]:
--- expected
+++ actual
@@ -1,3 +1,3 @@
 # encoding: UTF-8
 #    valid: true
-"This has an unclosed ]] here..."
+"This has an unclosed <![CDATA[]] here..."

[flavorjones]

I believe this is a duplicate of #2468. If you agree, we can close this issue.

Please note that Nokogiri's test suite runs against a vanilla ubuntu image running the distro's libxml2 and libxslt. If you'd ilke to add coverage for a redhat/fedora system I would accept a PR.

Please also note that we run CI against upstream libxml2 and libxslt master, and the failing tests are linked-to in #2468.

If there are other things you think we should be doing to test and maintain compatibility with downstream distros, please feel free to make suggestions, because right now I think I'm providing adequate support and attention.

[voxik]

Thx a lot. I'll follow the #2468.

I'll consider extending the CI!