[Python-modules-team] Bug#939457: lxml breaks beautifulsoup4 autopkgtest: a real XHTML didn't come out *exactly* the same as it went in

[Simon McVittie]

On Thu, 05 Sep 2019 at 09:56:41 +0200, Paul Gevers wrote:
> AssertionError: b'<?x[144 chars]xmlns="http://ns1/">\n<child
> xmlns="http://ns2[96 chars]ent>' != b'<?x[144
> chars]xmlns:="http://ns1/">\n<child xmlns:="http://n[99 chars]ent>'

"xmlns:=" (note the ":") is not a valid PrefixedAttName in
<https://www.w3.org/TR/xml-names/>, so this looks like a real bug being
detected by the test. Presumably something changed in lxml and/or in
bs4 that caused this to regress.

    smcv