charmbracelet/glow · error · errMsg

error rendering markdown: %w

Error message

error rendering markdown: %w

What it means

Thrown after the renderer exists, when r.Render(markdown) fails (ui/pager.go:384-387). This is the full markdown-to-ANSI pipeline: goldmark parsing, glamour's term rewriting and word wrapping, plus utils.WrapCodeBlock for non-markdown (code) files using the note's file extension. Failures bubble up from the goldmark parser or glamour's internal rendering, and are rare — when they fire, the input document or the active style is the culprit.

Source

Thrown at ui/pager.go:386

		utils.GlamourStyle(m.common.cfg.GlamourStyle, isCode),
		glamour.WithWordWrap(width),
	}

	if m.common.cfg.PreserveNewLines {
		options = append(options, glamour.WithPreservedNewLines())
	}
	r, err := glamour.NewTermRenderer(options...)
	if err != nil {
		return "", fmt.Errorf("error creating glamour renderer: %w", err)
	}

	if isCode {
		markdown = utils.WrapCodeBlock(markdown, filepath.Ext(m.currentDocument.Note))
	}

	out, err := r.Render(markdown)
	if err != nil {
		return "", fmt.Errorf("error rendering markdown: %w", err)
	}

	if isCode {
		out = strings.TrimSpace(out)
	}

	// trim lines
	lines := strings.Split(out, "\n")

	var content strings.Builder
	for i, s := range lines {
		if isCode || m.common.cfg.ShowLineNumbers {
			content.WriteString(m.common.styles.lineNumberStyle(fmt.Sprintf("%"+fmt.Sprint(lineNumberWidth)+"d", i+1)))
			content.WriteString(trunc(s))
		} else {
			content.WriteString(s)
		}

View on GitHub (pinned to e3970c813d)

Solutions

1. Reproduce outside the pager: `glow <file>` one-shot with the same style to isolate TUI vs render.
2. Rule out the style: retry with `--style=auto` (or light/dark).
3. Sanitize input: check `file <note>` and strip invalid UTF-8 (`iconv -f UTF-8 -t UTF-8//IGNORE`).
4. Bisect the document to find the offending construct and report a minimal repro to charmbracelet/glamour.
5. As a code-level guard, degrade to raw markdown instead of failing the pager (see exampleFix).

Example fix

// before
out, err := r.Render(markdown)
if err != nil {
	return "", fmt.Errorf("error rendering markdown: %w", err)
}

// after: keep the pager usable when glamour chokes on one document
out, err := r.Render(markdown)
if err != nil {
	log.Warn("glamour render failed, showing raw markdown", "error", err)
	out = markdown
}

if !utf8.ValidString(markdown) {
	markdown = strings.ToValidUTF8(markdown, "")
}

out, err := r.Render(markdown)
if err != nil {
	log.Warn("glamour render failed; falling back to raw markdown", "error", err)
	out = markdown
}

When it happens

Trigger: Paging a document with invalid UTF-8 bytes (e.g. fetched from a URL or a binary file misdetected as text); a custom style JSON that loads but breaks during rendering on specific constructs; pathological markdown (extreme nesting) choking the parser or reflow step; rendering a code file whose extension produces a WrapCodeBlock fence that trips goldmark.

Common situations: Browsing fetched READMEs or local code files in the glow TUI; files copied between systems with encoding damage; custom styles that pass loading but not rendering; glamour version changes altering render behavior.

Related errors

• unable to render markdown: %w
• unable to create renderer: %w
• error creating glamour renderer: %w
• could not load file: missing path
• error parsing config: %v

AI-assisted analysis of charmbracelet/glow@e3970c813d (2026-08-15). Data as JSON: /api/errors/e34c7f6edb472a52. Report an issue: GitHub.