Abbreviations within links within strike-throughs break Markdown to PDF generation

[benwbrum]

Explain the problem.
I'm trying to generate a PDF that has a a link within a strike-through. When the anchor text includes a title like Rev. A W McLum, the PDF generation fails. Further investigation shows that this appears with any string in the abbreviations file, followed by a space, if the string is nested within a link that is nested within a strike-through.

$ echo '~~[Sen. Jones](#footnote)~~' | pandoc --from markdown+superscript -o edited.tex --pdf-engine=xelatex  
$ cat edited.tex 
\sout{\protect\hyperlink{footnote}{Sen.~Jones}}

$ echo '~~[Sen. Jones](#footnote)~~' | pandoc --from markdown+superscript -o edited.pdf --pdf-engine=xelatex  
Error producing PDF.
! Extra }, or forgotten \endgroup.
\UL@stop ...z@ \else \UL@putbox \fi \else \egroup 
                                                  \egroup \UL@putbox \fi \if...
l.56 ...{\protect\hyperlink{footnote}{Sen.~Jones}}

This can be circumvented by not using the default abbreviations file, so that Markdown doesn't recognize Rev. or Sen. as an abbreviation:
$ echo '~~[Sen. Jones](#footnote)~~' | pandoc --from markdown+superscript -o edited.pdf --pdf-engine=xelatex --abbreviations=/dev/null

Pandoc version

$ pandoc -v
pandoc 2.19.2
Compiled with pandoc-types 1.22.2.1, texmath 0.12.5.2, skylighting 0.13,
citeproc 0.8.0.1, ipynb 0.2, hslua 2.2.1
Scripting engine: Lua 5.4
User data directory: /home/benwbrum/.local/share/pandoc
Copyright (C) 2006-2022 John MacFarlane. Web:  https://pandoc.org
This is free software; see the source for copying conditions. There is no
warranty, not even for merchantability or fitness for a particular purpose.
$ uname -a
Linux sparckjones 5.4.0-131-generic #147~18.04.1-Ubuntu SMP Sat Oct 15 13:10:18 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux

[jgm]

An easier way to defeat this is to escape the period: Sen\. Jones

[ickc]

I am experiencing the same issue with the following example:

❯ echo '~~[N comparison](example.com)~~' | pandoc -o temp.pdf 
Error producing PDF.
! Extra }, or forgotten \endgroup.
\UL@stop ...z@ \else \UL@putbox \fi \else \egroup 
                                                  \egroup \UL@putbox \fi \if...
l.56 \sout{\href{example.com}{N~comparison}}

[jgm]

@ickc this example does not raise an error for me.

[ickc]

After some confusion I found that the example I used has a unicode non-breaking space   where most probably the markdown rendered here turned that into normal space.

Hence it is equivalent to

❯ echo '~~[N\ comparison](example.com)~~' | pandoc -o temp.pdf 
Error producing PDF.
! Extra }, or forgotten \endgroup.
\UL@stop ...z@ \else \UL@putbox \fi \else \egroup 
                                                  \egroup \UL@putbox \fi \if...
l.56 \sout{\href{example.com}{N~comparison}}

where we know why it fails. What's not very obvious is when the source has a non-breaking space, it is hard to understand what's happening (even when I am using an editor that shows space and non-breaking space differently.)

The doc of ulem mentioned they only support ~ in underline. Are there anywhere discussed why we chose ulem instead of soul or changes here? (Probably changes is too new.)

[jgm]

The doc of ulem mentioned they only support ~ in underline. Are there anywhere discussed why we chose ulem instead of soul or changes here? (Probably changes is too new.)

See #7835

[ickc]

Seems like #7835 is not related? #5529 or others?

[ickc]

Or #7351, #2873.

[jgm]

I just decided to go with soul, we need it anyway for highlighting.

[ickc]

Notes for self and others: c.f. #7743 and commit 7543538.