markup: Handle attribute lists in code fences

Fixes #8278

1 files changed, 36 insertions, 5 deletions

diff --git a/markup/goldmark/render_hooks.go b/markup/goldmark/render_hooks.go
index 6bedc897e..41db4011b 100644
--- a/markup/goldmark/render_hooks.go
+++ b/markup/goldmark/render_hooks.go
@@ -14,8 +14,11 @@
 package goldmark
 
 import (
+	"bytes"
 	"sync"
 
+	"github.com/spf13/cast"
+
 	"github.com/gohugoio/hugo/markup/converter/hooks"
 
 	"github.com/yuin/goldmark"
@@ -135,13 +138,41 @@ func (r *hookedRenderer) RegisterFuncs(reg renderer.NodeRendererFuncRegisterer)
 	reg.Register(ast.KindHeading, r.renderHeading)
 }
 
-// https://github.com/yuin/goldmark/blob/b611cd333a492416b56aa8d94b04a67bf0096ab2/renderer/html/html.go#L404
-func (r *hookedRenderer) RenderAttributes(w util.BufWriter, node ast.Node) {
-	for _, attr := range node.Attributes() {
+func (r *hookedRenderer) renderAttributesForNode(w util.BufWriter, node ast.Node) {
+	renderAttributes(w, false, node.Attributes()...)
+}
+
+var (
+
+	// Attributes with special meaning that does not make sense to render in HTML.
+	attributeExcludes = map[string]bool{
+		"linenos":     true,
+		"hl_lines":    true,
+		"linenostart": true,
+	}
+)
+
+func renderAttributes(w util.BufWriter, skipClass bool, attributes ...ast.Attribute) {
+	for _, attr := range attributes {
+		if skipClass && bytes.Equal(attr.Name, []byte("class")) {
+			continue
+		}
+
+		if attributeExcludes[string(attr.Name)] {
+			continue
+		}
+
 		_, _ = w.WriteString(" ")
 		_, _ = w.Write(attr.Name)
 		_, _ = w.WriteString(`="`)
-		_, _ = w.Write(util.EscapeHTML(attr.Value.([]byte)))
+
+		switch v := attr.Value.(type) {
+		case []byte:
+			_, _ = w.Write(util.EscapeHTML(v))
+		default:
+			w.WriteString(cast.ToString(v))
+		}
+
 		_ = w.WriteByte('"')
 	}
 }
@@ -282,7 +313,7 @@ func (r *hookedRenderer) renderDefaultHeading(w util.BufWriter, source []byte, n
 		_, _ = w.WriteString("<h")
 		_ = w.WriteByte("0123456"[n.Level])
 		if n.Attributes() != nil {
-			r.RenderAttributes(w, node)
+			r.renderAttributesForNode(w, node)
 		}
 		_ = w.WriteByte('>')
 	} else {