On 07/06/2017 11:21, Joseph Wright wrote:
> On 07/06/2017 11:14, Alexander Grahn wrote:
>> Good afternoon,
>>
>> the recent version change of expl3 from [2017/04/01] (last TL-16 state) to
>> [2017/05/13] (initial TL-17 state) changed the behaviour of \hbox_s:Nn, which
>> made a hot-fix necessary for one of my packages (ocgx2) on CTAN.
>>
>> The problem boils down to the following code, which used to work with expl3 as
>> of v. 2017/04/01, but fails now with `! Missing } inserted.' error.
>>
>>   \documentclass{article}
>>   \usepackage{hyperref}
>>   
>>   \usepackage{expl3}
>>   \ExplSyntaxOn
>>   
>>   \begin{document}
>>   
>>   \href{https://www.ctan.org}{\dots
>>     \hbox_set:Nn0\bgroup CTAN    % broken since expl3 [2017/05/13]
>>   %  \setbox0=\hbox\bgroup CTAN  % hot-fix
>>     \egroup\box_use:N0
>>   \dots}
>>   
>>   \end{document}
>>
>> I would like to return to using \hbox_set:Nn instead of \setbox.
>>
>> Alexander
> 
> Hi Alexander,
> 
> I had an issue in siunitx which I also had to fix for this update: for
> me it boiled down to having made some implementation assumptions and
> ending up mixing different interfaces. 

Indeed, I've found I had a few more of these which I need to fix! It's
easy enough to assume primitive behaviour but really not a great plan: I
think in my own case the code goes back to before I joined the team (and
was feeling my way through the TeX <-> expl3 situation).

Joseph