anchorlinenos and lineanchors attributes do not work when using with code fences

[kaushalmodi]

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

$ hugo version
hugo v0.92.0-B3549403 linux/amd64 BuildDate=2022-01-12T08:23:18Z VendorInfo=gohugoio

Does this issue reproduce with the latest release?

Yes

Hugo Discourse discussion

https://discourse.gohugo.io/t/bug-anchorlinenos-true-attribute-doesnt-work-when-using-code-fences/36564

Reproducible example

• source repo
• Rendered HTML showing the issue
• Markdown content file

Steps to reproduce the problem

git clone https://gitlab.com/hugo-mwe/hugo-mwe
cd hugo-mwe
git checkout anchorlinenos
./srv.sh

Analysis

It looks like the anchorlinenos and lineanchors attributes get passed on as-is to the rendered HTML without being treated as special attributes for creating line number hyperlinks.

I see this when I look at the source of the above test HTML page:

Possibly related code:

hugo/markup/goldmark/render_hooks.go

Lines 149 to 154 in fcbbbef

	// Attributes with special meaning that does not make sense to render in HTML.
	attributeExcludes = map[string]bool{
	"linenos": true,
	"hl_lines": true,
	"linenostart": true,
	}

The link anchoring feature was added in fb0f2cc but the new attributes probably still need to be added in render_hooks.go. /cc @fjorgemota

[jmooring]

When using code fences, the available options are limited by the yuin/goldmark-highlighting module (upstream).

The hl_style option should be added to the attributeExcludes map (separate issue #9390).

More info:
https://discourse.gohugo.io/t/36564/3

[kaushalmodi]

I really wanted to move away from using the highlight shortcode completely because of #4717. But now I will use it only when I need to use anchorlinenos.

I'll close this issue given that this is recognized as an expected behavior.

[jmooring]

But now I will use it only when I need to use anchorlinenos

Or set the default in site configuration:

[markup.highlight]
anchorLineNos = true

[kaushalmodi]

@jmooring

Or set the default in site configuration

Yeah, I realized that that worked. But my sites have hundreds of code blocks and I don't want to enable the anchors for every line.

That makes me think.. why does enabling that variable in site config work even for code fences?

[kaushalmodi]

I think that if Hugo makes the anchorLineNos=true value propagate from the code fence attribute to wherever it needs to set, then this issue will be resolved. Because setting that var in the global site config definitely works.

[kaushalmodi]

@bep Can you please take a look at this?

Is it possible to make this work by any change from the Hugo side?

```emacs-lisp { linenos=table, anchorlinenos=true, lineanchors=org-coderef--xyz }
(save-excursion
   (goto-char (point-min))
```

Right now, the line anchors don't get enabled if we use code fences; they work only with the highlight shortcode.

1. I am seeing that you are refactoring a lot of code around goldmark code block rendering and I am hoping that this is a good time to fix this while you are working on that code base.
2. I haven't seen any response on [feature request] Support for linkable line numbers as supported by Chroma yuin/goldmark-highlighting#25.

[bep]

There are now 1 handling of this config so I assume that your case will now just work, but I would soonish merge my work into master branch, and would appreciate if "someone else" could verify this then.

[kaushalmodi]

@bep Thanks! Yes, the latest master has fixed this bug. To avoid regression, I added a small test in #9562. The test passed locally, but is failing in the CI for a reason I don't understand.

[github-actions]

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