I figured out the location of the link causing the error using the [draft]
option in the hyperref
package definition, as explained in this 2002 mailing list post by James A. Bednar:
... when this error occurs, write down the
page number where pdflatex aborted, then add the "draft" option to
hyperref:
\usepackage[draft]{hyperref}
and recompile the document. PDF output will now be generated, the
problematic link should be the citation whose latter half begins the
page where pdflatex aborted. After slightly rearranging the text to
avoid the linebreak, the [draft] option can be removed.
(I tried user22326's useful suggestion to use the [debug]
option in the hyperref
package definition, however, this didn't help me in finding the location (in the log, or in the latex file) of the link causing the error. Not even after I figured it out using the draft
option solution.)
The MWE is a good starting point. From there I could simplify it further. frontmatter
sets the title in the optional argument of \twocolumn
. Thus \twocolumn[]
is sufficient. The text can be replaced by vertical spaces.
The class can be replaced by the standard article
class.
MWE:
\documentclass{article}
\usepackage{hyperref}
\begin{document}
\twocolumn[]
\null\vfill\newpage
\null\kern.95\textheight
\href{http://tex.stackexchange.com}{This is a very very
very very very very very very very very very very very very very
very very very very very very very very long link.}
\end{document}
If \twocolumn
is called with the optional argument, then macro \@topnewpage
is called, which puts the stuff of the optional argument in a double column float object for the top of the page. Thus also the following triggers the problem instead of \twocolumn[]
:
\twocolumn
\begin{figure*}\end{figure*}
At some later time in the output routine, macro \@combinedblfloats
combines the top double float object with the normal page contents:
\setbox\@outputbox \vbox to\textheight{%
\unvbox\@tempboxa
\vskip-\dblfloatsep
\ifnum \@dbltopnum>\m@ne
\dblfigrule
\fi
\vskip \dbltextfloatsep
\box\@outputbox
}%
As can be seen, \@outputbox
is boxed again in an additional \vbox
.
Thus the box level of the first part of the link is higher by one in comparison to the second page without the double float object.
The following workaround increases the boxing level except for the first page:
\documentclass{article}
\usepackage{hyperref}
\AtBeginShipout{%
\ifnum\value{page}>1 %
\typeout{* Additional boxing of page `\thepage'}%
\setbox\AtBeginShipoutBox=\hbox{\copy\AtBeginShipoutBox}%
\fi
}
\begin{document}
\twocolumn[]
\null\vfill\newpage
\null\kern.95\textheight
\href{http://tex.stackexchange.com}{This is a very very
very very very very very very very very very very very very very
very very very very very very very very long link.}
\end{document}
The workaround also works with the original MWE of the question.
In real documents, it is not trivial to know, which pages would need
how many additional box levels.
A manual way would be using the following snippet, the first two lines quite early, even before \documentclass
, the remaining part should be executed late, here via \AtBeginDocument
.
\RequirePackage{atbegshi}
\AtBeginShipoutInit
\AtBeginDocument{%
\AtBeginShipout{%
\begingroup
\showboxdepth=\maxdimen
\showboxbreadth=\maxdimen
\tracingonline=1 %
\edef\restoreinteractionmode{\interactionmode=\the\interactionmode}%
\nonstopmode
\showbox\AtBeginShipoutBox
\restoreinteractionmode
\endgroup
}%
}
Then the box listings of the output pages can be analyzed to identify the start part of the link and the end part on the next page. Then the number of dots at the line starts need to be compared.
The next example tries a more automatic solution:
\documentclass[5p]{elsarticle}
\usepackage{kantlipsum}
\usepackage{hyperref}
\usepackage{etoolbox}
\makeatletter
\newcount\c@additionalboxlevel
\setcounter{additionalboxlevel}{0}
\newcount\c@maxboxlevel
\setcounter{maxboxlevel}{1}
\patchcmd\@combinedblfloats{\box\@outputbox}{%
\stepcounter{additionalboxlevel}%
\box\@outputbox
}{}{\errmessage{\noexpand\@combinedblfloats could not be patched}}
\AtBeginShipout{%
\ifnum\value{additionalboxlevel}>\value{maxboxlevel}%
\typeout{Warning: maxboxlevel might be too small, increase to %
\the\value{additionalboxlevel}%
}%
\fi
\@whilenum\value{additionalboxlevel}<\value{maxboxlevel}\do{%
\typeout{* Additional boxing of page `\thepage'}%
\setbox\AtBeginShipoutBox=\hbox{\copy\AtBeginShipoutBox}%
\stepcounter{additionalboxlevel}%
}%
\setcounter{additionalboxlevel}{0}%
}
\makeatother
\begin{document}
\begin{frontmatter}
\end{frontmatter}
\kant*[1-4]
\kant[5]
\href{http://tex.stackexchange.com}{This is a very very
very very very very very very very very very very very very very
very very very very very very very very long link.}
\end{document}
Maybe this issue could also be fixed by replacing \box\@outputbox
by \unvbox\@outputbox
in macro \@combinedblfloats
(maybe the vertical glue assignments might change):
\usepackage{etoolbox}
\makeatletter
\patchcmd\@combinedblfloats{\box\@outputbox}{\unvbox\@outputbox}{}{%
\errmessage{\noexpand\@combinedblfloats could not be patched}%
}%
\makeatother
Best Answer
According to Heiko Oberdiek, the bug was introduced with a change to
atbegshi
. Withhyperref v6.82r
, it should be fixed. I tested withv6.82v
(which hit texlive 2012 today) and the MWE runs properly without error.