gohugoio/hugo · error

no code renderer found for %q

Error message

no code renderer found for %q

What it means

Hugo's Goldmark code-block renderer resolves a render hook for every fenced code block via `GetRenderer(hooks.CodeBlockRendererType, lang)`. If no renderer is registered for the block's language — neither a user `render-codeblock` layout hook nor Hugo's built-in Chroma highlighter fallback — the AST walk stops and the page build fails naming the language string.

Source

Thrown at markup/goldmark/codeblocks/render.go:71

}

func (r *htmlRenderer) RegisterFuncs(reg renderer.NodeRendererFuncRegisterer) {
	reg.Register(ast.KindFencedCodeBlock, r.renderCodeBlock)
}

func (r *htmlRenderer) renderCodeBlock(w util.BufWriter, src []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
	ctx := w.(*render.Context)

	if entering {
		return ast.WalkContinue, nil
	}

	n := node.(*ast.FencedCodeBlock)

	lang := getLang(n, src)
	renderer := ctx.RenderContext().GetRenderer(hooks.CodeBlockRendererType, lang)
	if renderer == nil {
		return ast.WalkStop, fmt.Errorf("no code renderer found for %q", lang)
	}

	ordinal := ctx.GetAndIncrementOrdinal(ast.KindFencedCodeBlock)

	var buff bytes.Buffer

	l := n.Lines().Len()
	for i := range l {
		line := n.Lines().At(i)
		buff.Write(line.Value(src))
	}

	s := htext.Chomp(buff.String())

	var info []byte
	if n.Info != nil {
		info = n.Info.Segment.Value(src)
	}

View on GitHub ↗ (pinned to 8a468df065)

Solutions

1. Ensure the built-in fallback is available: leave markup.highlight.codeFences enabled (default true) so unhandled languages fall back to the Chroma renderer.
2. Add or restore a codeblock render hook for the language: layouts/_markup/render-codeblock-<lang>.html or a generic render-codeblock.html.
3. Fix the fence's info string if it contains a garbled/unintended language token.
4. If a theme provided the hook, confirm the theme module/version still ships it after upgrades.

Example fix

<!-- before: layouts has no hook and highlighting disabled -->
```mermaid
graph TD; A-->B;
```
<!-- after: add layouts/_markup/render-codeblock-mermaid.html -->
<pre class="mermaid">{{ .Inner | htmlEscape | safeHTML }}</pre>

// ensure a matching render hook exists for each fenced language you use, e.g.
// layouts/_markup/render-codeblock-mermaid.html for ```mermaid blocks

When it happens

Trigger: Rendering a markdown fenced code block whose info string maps to a language for which no code-block renderer resolves. In practice this surfaces when the built-in highlighter path is unavailable (e.g. `markup.highlight.codeFences=false` combined with hook lookup changes) or a custom `layouts/_markup/render-codeblock-<lang>.html` setup leaves a language unhandled in an edge configuration.

Common situations: Themes providing per-language codeblock render hooks (e.g. render-codeblock-mermaid.html) removed or renamed during a theme upgrade; disabling code fences / highlighting in config while content still relies on codeblock rendering; Hugo version changes in render-hook resolution order exposing unusual info strings (odd characters in the fence language).

Related errors

• project config markup.goldmark.renderHooks.image.useEmbedded
• project config markup.goldmark.renderHooks.link.useEmbedded
• unrecognized render hook template
• goldmark: %s
• failed to parse Markdown attributes; you may need to quote t

AI-assisted analysis of gohugoio/hugo@8a468df065 (2026-07-31). Data as JSON: /data/errors/b00e52a05d5fe084.json. Report an issue: GitHub ↗.