Infinite loop in sw_ooxmlexport17 unit test on macOS x86_64

[Patrick Luby]

Hi all,

I don't know if anyone is seeing their macOS Intel builds time out on 
Jenkins, but over the last week I have been seeing this happen 
frequently for my gerrit patch submissions.

I was able to track down the problem to an infinite loop that occurs in 
the sw_ooxmlexport17 unit test. This infinite loop is 100% reproducible 
when I run make check on master on my old Intel MacBook Pro despite 
rebasing to master and running a clean build each day.

I have not ever seen this infinite loop on my much faster macOS Silicon 
laptop so my guess is that this is a bug that only appears on slower 
machines.

I have submitted a patch that fixes this infinite loop, but IMHO it is 
just a quick hack and I know that my fix will terminate the layout loop 
early when opening, saving, printing, and exporting to PDF with a Writer 
document without huge text tables that span multiple pages:

https://gerrit.libreoffice.org/c/core/+/143947/4

Does anyone have any suggestions or idea for a better way to fix this 
bug other than my quick hack?

Patrick