missing dependencies on ruby-sinatra, ruby-rack for -S

[Mark Eichin]

To reproduce: grab a beta-1 ubuntu bionic iso, select "minimal install", apt install ruby-ronn, run "ruby-ronn -S ." and get:

eichin@vm-bionic-1:~$ ronn -S .
Traceback (most recent call last):
        5: from /usr/bin/ronn:140:in `<main>'
        4: from /usr/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in `require'
        3: from /usr/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in `require'
        2: from /usr/lib/ruby/vendor_ruby/ronn/server.rb:2:in `<top (required)>'
        1: from /usr/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in `require'
/usr/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in `require': cannot load such file -- rack (LoadError)

apt install ruby-rack gives:

/usr/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in `require': cannot load such file -- sinatra/base (LoadError)

Finally, apt install ruby-sinatra yields a working server. (I suspect they were previously satisfied indirectly by something else; I don't know when the problem appeared beyond "it was fine in 16.04 and it's not fine in 18.04.")

[Hans Joachim Desserud (hjd)]

Thanks for taking your time to report this issue and help making Ubuntu better.

I can confirm this issue with ruby-ronn 0.7.3-5 on Ubuntu bionic. However, I'm not familiar with this package, so I took a look at the manpage to see what the -S option was doing:

       -S, --server
              Don´t generate files, start an HTTP server at http://localhost:1207/ and serve dynamically generated HTML for the set of input files. A file named example.2.ronn is served as /example.2.html. There´s also an
              index page at the root with links to each file.

              The server respects the --style and document attribute options (--manual, --date, etc.). These same options can be varied at request time by giving them as query parameters: ?manual=FOO&style=dark,toc

              NOTE: The builtin server is designed to assist in the process of writing and styling manuals. It is in no way recommended as a general purpose web server.

(http://manpages.ubuntu.com/manpages/bionic/en/man1/ronn.1.html)

The obvious fix seems to be to alway include rack and sinatra as dependencies, but especially based on the last sentence I don't know how common this use case is. Maybe they should be suggested dependencies?