So I was running this:

/var/www/jj-web-1-www.jj5.net-sixsigma:
  file.recurse:
    - clean: True
    - user: root
    - group: root
    - dir_mode: 755
    - file_mode: 644
    - source: salt://inst/mediawiki-1.29
    - require:
      - pkg: apache2

And getting an error like this:

----------
          ID: /var/www/jj-web-1-www.jj5.net-sixsigma
    Function: file.recurse
      Result: False
     Comment: #### /var/www/jj-web-1-www.jj5.net-sixsigma/vendor/james-heinrich/getid3/getid3/module.audio.ac3.php ####
              Source file 'salt://inst/mediawiki-1.29/vendor/james-heinrich/getid3/getid3/module.audio.ac3.php?saltenv=base' not found

              #### /var/www/jj-web-1-www.jj5.net-sixsigma/vendor/james-heinrich/getid3/getid3/module.audio-video.mpeg.php ####
              Source file 'salt://inst/mediawiki-1.29/vendor/james-heinrich/getid3/getid3/module.audio-video.mpeg.php?saltenv=base' not found
     Started: 14:27:18.352264
    Duration: 134735.945 ms
     Changes:
----------

The issue was that the source files mentioned weren’t in UTF-8 format. To convert the files I ran, e.g.:

$ iconv -f WINDOWS-1252 -t UTF-8//TRANSLIT < module.audio-video.mpeg.php.bak > module.audio-video.mpeg.php

(Actually I couldn’t get the ‘iconv’ command to work so I edited manually in Vim)