Possible bug in makexindex

[Ulrike Fischer]

Am Wed, 7 Aug 2024 14:53:28 -0600 schrieb Karl Berry:

>     uf> I would say it is a bug in makeindex.
> 
> Ok, I'll take your word for it. But can someone please make a plain TeX
> example that is much more minimal, that is, produces only the incorrect
> output?  

You can simply use the entries directly. Save this as test.idx


\indexentry{aaa}{1}
\indexentry{aaa!bbb}{1}
\indexentry{aaa}{2}
\indexentry{aaa!bbb}{2}
\indexentry{xxx}{1}
\indexentry{xxx!yyy}{1}


and this as simple.ist

item_1 "\n \\subitem (item\\_1) "
item_01 "\n \\subitem (item\\_01) "

then you can run 

makeindex -s simple test.idx


You then get 

\begin{theindex}

  \item aaa, 1, 2
 \subitem (item\_1) bbb, 1, 2

  \indexspace

  \item xxx, 1
 \subitem (item\_01) yyy, 1

\end{theindex}

if you run

upmendex -s simple test.idx

you get

\begin{theindex}

  \item aaa, 1, 2
 \subitem (item\_01) bbb, 1, 2

  \indexspace

  \item xxx, 1
 \subitem (item\_01) yyy, 1

\end{theindex}

Remark the difference between \subitem (item\_1) and \subitem
(item\_01) in the aaa entry, while the xxx entry is the same for
both.


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