# [Dev-luatex] keeping in sync with pdftex changes

Ulrike Fischer news3 at nililand.de
Mon Jan 11 18:12:15 CET 2021

Am Mon, 11 Jan 2021 17:09:38 +0100 schrieb Hans Hagen:

>>> I don't like the idea that something wrong now suddenly becomes right ---
>>
>> Well I never understood why this is a fatal error.  Why does pdftex
>> or luatex care in my example about the boxing level? The worst that
>> can happen is that pdftex calculates a wrong link area, so a warning
>> makes sense. But the pdf is valid and there is imho (like with
>> duplicated or missing destination names) no real reason to stop
>> alltogether.

> If that is the new criterium for error or no error,

Why new? There are already a number of "errors" which only give
warnings or info, e.g.
destination with the same identifier ...
or
(\end occurred inside a group at level 1)

or from the user view actually often quite problematic the
Missing Character message.

So you always have to consider if you think an error is fatal or
not.

And in the case of links it is actually quite unclear why it should
be an error at all. There is nothing logically wrong with the idea
to have the "stop" marker in some other box level.

dvipdfmx doesn't give a fatal error either: it uses the box level to
decide if something is part of the link or not, but the eann special
can be in any level:

x\hbox{\special{pdf:bann
/A<<%
/Type/Action
/S/URI
/URI(blkub)
>>>>}
\special{pdf:eann}
\bye

(It is not an very important change. The one case in LaTeX where it
really mattered has been resolve by adjusting the box levels. I only
mentioned it here too, so that you can consider it. The ability to
stop a running link is much more needed.)

--
Ulrike Fischer
https://www.troubleshooting-tex.de/