How can I force kramdown (or Nanoc) to generate <br> instead of <br /> for line breaks?

Question

I’m using kramdown with static site generator Nanoc to generate HTML from Markdown.

By default, kramdown is generating Markdown double-spaces as XHTML-friendly <br /> instead of HTML5's <br>, so the HTML5 validator is “informing” about this:

Info: Trailing slash on void elements has no effect and interacts badly with unquoted attribute values.
From line … (etc)
text_here.<br />

Is there a kramdown or Nanoc option/command to force <br> instead of <br /> for line breaks indicated by double-spaces at a line end?

Answer 1

Edit the html.rb file in (…)/gems/kramdown/

I found the location of the relevant code on line 267 of the HTML converter in:

"/usr/local/lib/ruby/gems/3.2.0/gems/kramdown-2.4.0/lib/kramdown/converter/html.rb" (my Ruby is Homebrew-installed)

and (sudo) edited <br /> to <br> with Micro (command-line editor: brew install micro) to preserve the file’s permissions and ownership.

Then recompiled a Markdown file with double-space line breaks and am now seeing <br> instead of <br />. Also did the same for other self-closing HTML5 tags (img and hr) as well as the places where kramdown parses self-closing tags in raw HTML inside Markdown files - just replaced /> with >, carefully, and manually. Now getting nice HTML5 output that the validator likes.

You can see the HTML converter on the kramdown GitHub repo.

However, I presume any update to the kramdown gem will overwrite it - so if anyone knows how to make this change permanent for a local kramdown gem, advice is welcome. See this post on the kramdown Google group