Compilation fails when \cite{} is added

[RMeli]

Compilation fails when \cite{} is added. MWE below, but this also happens on more complex files where \cite{} is not empty.

---

File zero.tex:

\documentclass{article}
\begin{document}
Without reference.
\end{document}

File one.tex:

\documentclass{article}
\begin{document}
With reference \cite{}.
\end{document}

---

diff.tex (obtained with latexdiff zero.tex one.tex > diff.tex):

\documentclass{article}
%DIF LATEXDIFF DIFFERENCE FILE
%DIF DEL zero.tex   Mon Jul 12 18:13:38 2021
%DIF ADD one.tex    Mon Jul 12 18:13:37 2021
%DIF PREAMBLE EXTENSION ADDED BY LATEXDIFF
%DIF UNDERLINE PREAMBLE %DIF PREAMBLE
\RequirePackage[normalem]{ulem} %DIF PREAMBLE
\RequirePackage{color}\definecolor{RED}{rgb}{1,0,0}\definecolor{BLUE}{rgb}{0,0,1} %DIF PREAMBLE
\providecommand{\DIFadd}[1]{{\protect\color{blue}\uwave{#1}}} %DIF PREAMBLE
\providecommand{\DIFdel}[1]{{\protect\color{red}\sout{#1}}}                      %DIF PREAMBLE
%DIF SAFE PREAMBLE %DIF PREAMBLE
\providecommand{\DIFaddbegin}{} %DIF PREAMBLE
\providecommand{\DIFaddend}{} %DIF PREAMBLE
\providecommand{\DIFdelbegin}{} %DIF PREAMBLE
\providecommand{\DIFdelend}{} %DIF PREAMBLE
\providecommand{\DIFmodbegin}{} %DIF PREAMBLE
\providecommand{\DIFmodend}{} %DIF PREAMBLE
%DIF FLOATSAFE PREAMBLE %DIF PREAMBLE
\providecommand{\DIFaddFL}[1]{\DIFadd{#1}} %DIF PREAMBLE
\providecommand{\DIFdelFL}[1]{\DIFdel{#1}} %DIF PREAMBLE
\providecommand{\DIFaddbeginFL}{} %DIF PREAMBLE
\providecommand{\DIFaddendFL}{} %DIF PREAMBLE
\providecommand{\DIFdelbeginFL}{} %DIF PREAMBLE
\providecommand{\DIFdelendFL}{} %DIF PREAMBLE
%DIF LISTINGS PREAMBLE %DIF PREAMBLE
\RequirePackage{listings} %DIF PREAMBLE
\RequirePackage{color} %DIF PREAMBLE
\lstdefinelanguage{DIFcode}{ %DIF PREAMBLE
%DIF DIFCODE_UNDERLINE %DIF PREAMBLE
  moredelim=[il][\color{red}\sout]{\%DIF\ <\ }, %DIF PREAMBLE
  moredelim=[il][\color{blue}\uwave]{\%DIF\ >\ } %DIF PREAMBLE
} %DIF PREAMBLE
\lstdefinestyle{DIFverbatimstyle}{ %DIF PREAMBLE
    language=DIFcode, %DIF PREAMBLE
    basicstyle=\ttfamily, %DIF PREAMBLE
    columns=fullflexible, %DIF PREAMBLE
    keepspaces=true %DIF PREAMBLE
} %DIF PREAMBLE
\lstnewenvironment{DIFverbatim}{\lstset{style=DIFverbatimstyle}}{} %DIF PREAMBLE
\lstnewenvironment{DIFverbatim*}{\lstset{style=DIFverbatimstyle,showspaces=true}}{} %DIF PREAMBLE
%DIF END PREAMBLE EXTENSION ADDED BY LATEXDIFF

\begin{document}
\DIFdelbegin \DIFdel{Without reference }\DIFdelend \DIFaddbegin \DIFadd{With reference \mbox{%DIFAUXCMD
\cite{}}\hspace{0pt}%DIFAUXCMD
}\DIFaddend .
\end{document}

Compilation fails with the following error:

Rc files read:
  NONE
Latexmk: This is Latexmk, John Collins, 29 September 2020, version: 4.70b.
Rule 'pdflatex': The following rules & subrules became out-of-date:
      'pdflatex'
------------
Run number 1 of rule 'pdflatex'
------------
------------
Running 'pdflatex  -synctex=1 -interaction=nonstopmode -file-line-error -recorder -output-directory="/Users/rmeli/Desktop/latexdiff"  "/Users/rmeli/Desktop/latexdiff/diff.tex"'
------------
Set environment variable BIBINPUTS='/Users/rmeli/Desktop/latexdiff:'
Set environment variable TEXINPUTS='/Users/rmeli/Desktop/latexdiff:'
Latexmk: applying rule 'pdflatex'...
This is pdfTeX, Version 3.141592653-2.6-1.40.22 (TeX Live 2021) (preloaded format=pdflatex)
 restricted \write18 enabled.
entering extended mode
(/Users/rmeli/Desktop/latexdiff/diff.tex
LaTeX2e <2020-10-01> patch level 4
L3 programming layer <2021-02-18> (/usr/local/texlive/2021/texmf-dist/tex/latex/base/article.cls
Document Class: article 2020/04/10 v1.4m Standard LaTeX document class
(/usr/local/texlive/2021/texmf-dist/tex/latex/base/size10.clo)) (/usr/local/texlive/2021/texmf-dist/tex/generic/ulem/ulem.sty) (/usr/local/texlive/2021/texmf-dist/tex/latex/graphics/color.sty (/usr/local/texlive/2021/texmf-dist/tex/latex/graphics-cfg/color.cfg) (/usr/local/texlive/2021/texmf-dist/tex/latex/graphics-def/pdftex.def)) (/usr/local/texlive/2021/texmf-dist/tex/latex/listings/listings.sty (/usr/local/texlive/2021/texmf-dist/tex/latex/graphics/keyval.sty) (/usr/local/texlive/2021/texmf-dist/tex/latex/listings/lstmisc.sty) (/usr/local/texlive/2021/texmf-dist/tex/latex/listings/listings.cfg)) (/usr/local/texlive/2021/texmf-dist/tex/latex/l3backend/l3backend-pdftex.def) (/Users/rmeli/Desktop/latexdiff/diff.aux) (/usr/local/texlive/2021/texmf-dist/tex/context/base/mkii/supp-pdf.mkii
[Loading MPS to PDF converter (version 2006.09.02).]
)
/Users/rmeli/Desktop/latexdiff/diff.tex:46: Extra }, or forgotten \endgroup.
\UL@stop ...z@ \else \UL@putbox \fi \else \egroup 
                                                  \egroup \UL@putbox \fi \if...
l.46 }
      \DIFaddend .
/Users/rmeli/Desktop/latexdiff/diff.tex:46: Extra }, or forgotten \endgroup.
\UL@stop ... \UL@putbox \fi \else \egroup \egroup 
                                                  \UL@putbox \fi \ifnum \UL@...
l.46 }
      \DIFaddend .
/Users/rmeli/Desktop/latexdiff/diff.tex:46: Missing } inserted.
<inserted text> 
                }
l.46 }
      \DIFaddend .
/Users/rmeli/Desktop/latexdiff/diff.tex:46: Missing } inserted.
<inserted text> 
                }
l.46 }
      \DIFaddend .
[1{/usr/local/texlive/2021/texmf-var/fonts/map/pdftex/updmap/pdftex.map}] (/Users/rmeli/Desktop/latexdiff/diff.aux) )
(see the transcript file for additional information)</usr/local/texlive/2021/texmf-dist/fonts/type1/public/amsfonts/cm/cmr10.pfb></usr/local/texlive/2021/texmf-dist/fonts/type1/public/amsfonts/latxfont/lasy6.pfb>
Output written on /Users/rmeli/Desktop/latexdiff/diff.pdf (1 page, 15136 bytes).
SyncTeX written on /Users/rmeli/Desktop/latexdiff/diff.synctex.gz.
Transcript written on /Users/rmeli/Desktop/latexdiff/diff.log.
Latexmk: Log file says output to 'diff.pdf'
Collected error summary (may duplicate other messages):
  pdflatex: Command for 'pdflatex' gave return code 1
      Refer to '/Users/rmeli/Desktop/latexdiff/diff.log' for details
Latexmk: Use the -f option to force complete processing,
 unless error was exceeding maximum runs, or warnings treated as errors.
Latexmk: Examining '/Users/rmeli/Desktop/latexdiff/diff.log'
=== TeX engine is 'pdfTeX'
Latexmk: Errors, so I did not complete making targets

---

OS: macOS 11.4 latexdiff: LATEXDIFF 1.3.1.1 (Algorithm::Diff 1.15 so, Perl v5.30.2)

[RMeli]

This is actually a duplicate of #218, but fixes are not yet included in the latest version.

[ccaprani]

FWIW, replicated using LATEXDIFF 1.3.1a (Algorithm::Diff 1.15 fast, Perl v5.32.1). Removing the \hspace{0pt} worked (found #218 after...c'est la vie).

[LuminousXLB]

I met the issue as well. But it seems to have been solved in 1.3.2.

[ftilmann]

It seems this is fixed now. Closing