hyperref will trigger the compile error.

[Hongyi Zhao]

Hi here,

Currently, I'm using the iucr package [1] to write a paper, but I find
the following setting with hyperref will trigger a compile error:

```
$ cat test.tex
\documentclass{iucr}
\usepackage[unicode=true,
 bookmarks=true,bookmarksnumbered=false,bookmarksopen=false,
 breaklinks=false,pdfborder={0 0
0},pdfborderstyle={},backref=false,colorlinks=true]
 {hyperref}
\begin{document}

 This is a test!

\end{document}

$ pdflatex test.tex
This is pdfTeX, Version 3.141592653-2.6-1.40.25 (TeX Live 2023)
(preloaded format=pdflatex)
 restricted \write18 enabled.
entering extended mode
(./test.tex
LaTeX2e <2022-11-01> patch level 1
L3 programming layer <2023-04-20> (./iucr.cls
Document Class: iucr 2021/03/05 IUCr article/chapter class
(/opt/texlive/2023/texmf-dist/tex/latex/tools/multicol.sty)
(/opt/texlive/2023/texmf-dist/tex/latex/psnfss/times.sty)
(/opt/texlive/2023/texmf-dist/tex/latex/graphics/graphics.sty
(/opt/texlive/2023/texmf-dist/tex/latex/graphics/trig.sty)
(/opt/texlive/2023/texmf-dist/tex/latex/graphics-cfg/graphics.cfg)
(/opt/texlive/2023/texmf-dist/tex/latex/graphics-def/dvips.def))
(/opt/texlive/2023/texmf-dist/tex/latex/float/float.sty)
(/opt/texlive/2023/texmf-dist/tex/latex/tools/tabularx.sty
(/opt/texlive/2023/texmf-dist/tex/latex/tools/array.sty))
(/opt/texlive/2023/texmf-dist/tex/generic/dvips/colordvi.tex)
(/opt/texlive/2023/texmf-dist/tex/latex/base/article.cls
Document Class: article 2022/07/02 v1.4n Standard LaTeX document class
(/opt/texlive/2023/texmf-dist/tex/latex/base/size10.clo))
(/opt/texlive/2023/texmf-dist/tex/latex/harvard/harvard.sty
(/opt/texlive/2023/texmf-dist/tex/latex/base/ifthen.sty)
(/opt/texlive/texmf-local/tex/latex/html/html.sty
(/opt/texlive/2023/texmf-dist/tex/latex/hyperref/hyperref.sty
(/opt/texlive/2023/texmf-dist/tex/generic/ltxcmds/ltxcmds.sty)
(/opt/texlive/2023/texmf-dist/tex/generic/iftex/iftex.sty)
(/opt/texlive/2023/texmf-dist/tex/generic/pdftexcmds/pdftexcmds.sty
(/opt/texlive/2023/texmf-dist/tex/generic/infwarerr/infwarerr.sty))
(/opt/texlive/2023/texmf-dist/tex/latex/graphics/keyval.sty)
(/opt/texlive/2023/texmf-dist/tex/latex/kvsetkeys/kvsetkeys.sty)
(/opt/texlive/2023/texmf-dist/tex/generic/kvdefinekeys/kvdefinekeys.sty)
(/opt/texlive/2023/texmf-dist/tex/generic/pdfescape/pdfescape.sty)
(/opt/texlive/2023/texmf-dist/tex/latex/hycolor/hycolor.sty)
(/opt/texlive/2023/texmf-dist/tex/latex/letltxmacro/letltxmacro.sty)
(/opt/texlive/2023/texmf-dist/tex/latex/auxhook/auxhook.sty)
(/opt/texlive/2023/texmf-dist/tex/latex/hyperref/nameref.sty
(/opt/texlive/2023/texmf-dist/tex/latex/refcount/refcount.sty)
(/opt/texlive/2023/texmf-dist/tex/generic/gettitlestring/gettitlestring.sty
(/opt/texlive/2023/texmf-dist/tex/latex/kvoptions/kvoptions.sty)))
(/opt/texlive/2023/texmf-dist/tex/latex/etoolbox/etoolbox.sty)
(/opt/texlive/2023/texmf-dist/tex/latex/hyperref/pd1enc.def)
(/opt/texlive/2023/texmf-dist/tex/generic/intcalc/intcalc.sty)
(/opt/texlive/2023/texmf-dist/tex/latex/hyperref/puenc.def)
(/opt/texlive/2023/texmf-dist/tex/latex/url/url.sty)
(/opt/texlive/2023/texmf-dist/tex/generic/bitset/bitset.sty
(/opt/texlive/2023/texmf-dist/tex/generic/bigintcalc/bigintcalc.sty))
(/opt/texlive/2023/texmf-dist/tex/latex/base/atbegshi-ltx.sty))
(/opt/texlive/2023/texmf-dist/tex/latex/hyperref/hpdftex.def
(/opt/texlive/2023/texmf-dist/tex/latex/base/atveryend-ltx.sty)
(/opt/texlive/2023/texmf-dist/tex/latex/rerunfilecheck/rerunfilecheck.sty
(/opt/texlive/2023/texmf-dist/tex/generic/uniquecounter/uniquecounter.sty)))))
FONT WARNINGS CAN USUALLY BE IGNORED. IF YOU EXPERIENCE
PROBLEMS WITH FONTS, USE THE [preprint] OPTION
(/opt/texlive/2023/texmf-dist/tex/latex/psnfss/ot1ptmcm.fd)
(/opt/texlive/2023/texmf-dist/tex/latex/psnfss/omlptmcm.fd)
(/opt/texlive/2023/texmf-dist/tex/latex/psnfss/ot1ptm.fd))

! LaTeX Error: Missing \begin{document}.

See the LaTeX manual or LaTeX Companion for explanation.
Type  H <return>  for immediate help.
 ...

l.6 \begin
          {document}
?
```

See here [2] for the related discussion.

[1] https://journals.iucr.org/d/services/latexstyle.html
[2] https://github.com/latex3/hyperref/issues/279

Regards,
Zhao
-- 
Assoc. Prof. Hongsheng Zhao <hongyi.zhao at gmail.com>
Theory and Simulation of Materials
Hebei Vocational University of Technology and Engineering
No. 473, Quannan West Street, Xindu District, Xingtai, Hebei province