[asciidoctor] Missing code highlighter stylesheet

[anlar]

What version of Hugo are you using (hugo version)?

$ hugo version
hugo v0.107.0-2221b5b30a285d01220a26a82305906ad3291880+extended linux/amd64 BuildDate=2022-11-24T13:59:45Z VendorInfo=gohugoio

Does this issue reproduce with the latest release?

Yes.

Details

I'm using Hugo to process Asciidoc articles with Coderay highlighter, with the following config.toml:

# MAIN

baseURL = '/'
languageCode = 'en'
title = 'Blog title'
theme = 'mainroad'

# SECURITY

# required to access asciidoctor
[security.exec]
allow = ["^dart-sass-embedded$", "^go$", "^npx$", "^postcss$", "^asciidoctor$"]

# ASCIIDOCTOR

[markup.asciidocExt]
  extensions = ["asciidoctor-diagram"]
  workingFolderCurrent = true
  [markup.asciidocExt.attributes]
    source-highlighter = "coderay"

With this config Hugo correctly renders code blocks (so they are wrapped in <pre class="CodeRay highlight">). Problem is that CSS for CodeRay is not included in result pages automatically.

As a workaround I could either:

• Add coderay.css directly to my theme;
• Add coderay.css to static directory of my site and link to it in my theme.

Not sure if it is expected behavior or bug. But if it is expected there should be a note in External Helper Asciidoctor documentation.

[foo-dogsquared]

I've also done similar workarounds to make Asciidoctor work with rouge highlighter. The stylesheet are linked in the header which Hugo removes by adding --no-header-or-footer in the resulting conversion command. Though this could be configured to behave differently, it is closer to an expected behavior rather than a bug. I agree that this should be documented somehwere.

[hybras]

This is indeed expected behavior. Your workarounds are correct.