latexmk doesn't seem to act on my custom dependency for makeindex

Question

I am trying to get a document to print a list of urls, and I have the sample here that needs me to run makeindex in between the invocations of pdflatex. latexmk -pdf doesn't seem to do it automatically, although I thought it would convert .idx files to .ind files and re-run pdflatex automatically.

Manually, this is how it works: I have a main.tex file.

$ pdflatex main      # produces main-url.idx and main-url.mst
$ makeindex main-url # produces main-url.ind
$ pdflatex main      # produces a pdf with the index .ind file just created

As I understand it, latexmk takes care of running makeindex automatically, but when I run it on a clean directory (with only main.tex), the .ind file is never created, and the index doesn't end up in the pdf.

What I have tried: First, I tried adding the following dependency to a local latexmkrc file, but that didn't work (I think because there is already a rule to turn .idx files into .ind files:

# support for the printing urls:
add_cus_dep('idx', 'ind', 0, 'makeurlindex');
sub makeurlindex {
  return system("makeindex \"$_[0].idx\"");
}

Then I tried changing the output extension to .ndx and having the custom dependency as follows, but again, no dice:

# support for the printing urls:
add_cus_dep('ndx', 'ind', 0, 'makeurlindex');
sub makeurlindex {
  return system("makeindex \"$_[0].ndx\"");
}

Additionally, I tried changing the output file to main.idx and updated the custom dependency accordingly, but it didn't work, either.

Finally, I tried making the dependency go from .mst to .ind, but that didn't work.

How can I make latexmk act on this dependency?

Answer 1

I determined a way to use the regular idx->ind dependency handling, which was to provide a log message in the latex file:

\wlog{}
\wlog{Writing index file \jobname-url.idx}

The extra log message is to force a newline before the actual message.

This enabled the latexmk script to find the index message and handle it.