imakeidx biblatex indexes not being placed in the correct locations

Question

I am attempting to create three indexes for a document (subject, author and title) but the author and subject indexes are being loaded into the incorrect sections. I have tried changing \DeclareIndexNameFormat{default} to DeclareIndexFieldFormat{default} and modifying {default} to other strings like indexname but to no avail. Loading splitindex with \usepackage[xindy]{imakeidx} causes TexWorks to crash too so not sure if that is relevant or needed in this case.

%! MWE Example
% arara: lualatex
% arara: biber
% arara: lualatex
% arara: xindy: {modules: [texindy], codepage: utf8, language: english}
% arara: lualatex: {shell: yes}
% arara: lualatex
\documentclass[oneside]{memoir}
\usepackage[backend=biber,      
        hyperref=true,          
        indexing=true,                  
        natbib=true,        
        ]{biblatex}
\usepackage[xindy]{imakeidx}
\usepackage{hyperref}
\begin{filecontents}{\jobname.bib}
@article{Che20,
author = {Chen, Keqiang and Wang, Cong and Peng, Zhuoyin and Qi, Kun and Guo, Zhinan and Zhang, Yupeng and Zhang, Han},
title = {{The chemistry of colloidal semiconductor nanocrystals: From metal-chalcogenides to emerging perovskite}},
year = {2020}
}
@article{Hak20,
author = {Hakkoymaz, Orhun and Mazi, Hidayet},
title = {{An immobilized invertase enzyme for the selective determination of sucrose in fruit juices}},
year = {2020}
}
\end{filecontents}
\addbibresource{\jobname.bib}
\makeindex[intoc=true,
            program=xindy,
            title={Subject Index}]

\makeindex[intoc=true,
             title={Author Index},
             program=xindy,
             name=names]
{\DeclareIndexNameFormat{default}{%
   \usebibmacro{index:name}{\index[names]}
     {\namepartfamily}
     {\namepartgiven}
     {\namepartprefix}
     {\namepartsuffix}}}
\makeindex[intoc=true,

             title={Title Index},
             program=xindy,
             name=titles]
\DeclareIndexFieldFormat{indextitle}{%
  \usebibmacro{index:title}{\index[titles]}{#1}}%
\begin{document}
\cite{Che20, Hak20}
\printindex
\printindex[titles]
\printindex[names]
\end{document}

The subject index (the default index with no name= attached) is loading the authors:

Whereas the author index is loading nothing even though I have called them in the correct order at the end of my MWE:

I want to use xindy as I like its formatting but it is causing me grief and I do not know if I am even calling it with arara correctly either, any help would be appreciated.

Answer 1

There is an excess pair of curly braces around the \DeclareIndexNameFormat{default}. This pair of braces keeps the definition local, which means that it is immediately discarded. So the name indexing does not use your new names index.

Remove the curly braces around \DeclareIndexNameFormat{default}.

%! MWE Example
% arara: lualatex
% arara: biber
% arara: lualatex
% arara: xindy: {modules: [texindy], codepage: utf8, language: english}
% arara: lualatex: {shell: yes}
% arara: lualatex
\documentclass[oneside]{memoir}
\usepackage[backend=biber,
        indexing=true,
        natbib=true,
        ]{biblatex}
\usepackage[xindy]{imakeidx}
\usepackage{hyperref}
\makeindex[intoc=true,
           program=xindy,
           title={Subject Index}]
\makeindex[intoc=true,
           title={Author Index},
           program=xindy,
           name=names]
\DeclareIndexNameFormat{default}{%
  \usebibmacro{index:name}{\index[names]}
    {\namepartfamily}
    {\namepartgiven}
    {\namepartprefix}
    {\namepartsuffix}}
\makeindex[intoc=true,
             title={Title Index},
             program=xindy,
             name=titles]
\DeclareIndexFieldFormat{indextitle}{%
  \usebibmacro{index:title}{\index[titles]}{#1}}%
\addbibresource{biblatex-examples.bib}
\begin{document}
\cite{sigfridsson, worman,geer}
\printindex
\printindex[titles]
\printindex[names]
\end{document}