bug#70076: 28.3; xml-escape-string parse issue

[D. Schmudde]

Okay, good to know. Thanks for taking a look.

Here is some additional context. It occurs when using Elfeed's 
~elfeed-export-opml~ on my list of RSS feeds. It seems the library 
relies on ~xml-escape-string~ to parse each element. It's worth 
noting that this happens on several feeds, not just the feed for 
leancrew.com listed below.

I can file a bug with the package maintainers but I wasn't sure if 
the XML parser was a better place to start. Here is the specific 
backtrace, if it's useful:

Debugger entered--Lisp error: (xml-invalid-character 4194274 11)
 signal(xml-invalid-character (4194274 11))
 xml-escape-string("And now it\342\200\231s all this")
 xml-debug-print-internal((outline ((xmlUrl 
 . "https://leancrew.com/all-this/feed/";) (title . "And now 
 it\342\200\231s all this"))) "    ")
 ...

/David

Eli Zaretskii <eliz@gnu.org> writes:

> > Cc: Protesilaos Stavrou <public@protesilaos.com>
> > From: "D. Schmudde" <d@schmud.de>
> > Date: Fri, 29 Mar 2024 16:44:48 +0100
> >
> > Starting with `emacs -Q`:
> >
> > (require 'xml)
> > (xml-escape-string "And now it\342\200\231s all this")
> >
> > The result is: `xml-escape-string: Invalid XML character: 
> > 4194274,
> > 11`
> >
> > I expect that the string will parse correctly with these escape
> > characters. Or is this expectation wrong?
>
> Your expectation is wrong, AFAIU: you are inserting a unibyte 
> string
> (a string made out of raw bytes) instead of inserting a 
> non-ASCII
> multibyte string, which is what XML expects.
>
> Why did you need to insert those bytes, and where did they come 
> from?


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