Exclude Children of Draft Parents in Hugo Sitemap

sitemap.xml

{{/* gotmplfmt-ignore-all */ -}}
{{ printf "<?xml version=\"1.0\" encoding=\"utf-8\" standalone=\"yes\"?>" | safeHTML }}
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9" xmlns:xhtml="http://www.w3.org/1999/xhtml">
  {{ range where .Pages "Sitemap.Disable" "ne" true }}
    {{- $hasAncestorDraft := false -}}
    {{- range .Ancestors -}}
      {{- if .Draft -}}
        {{- $hasAncestorDraft = true -}}
      {{- end -}}
    {{- end -}}
    {{- if and .Permalink (not $hasAncestorDraft) -}}
  <url>
    <loc>{{ .Permalink }}</loc>{{ if not .Lastmod.IsZero }}
    <lastmod>{{ safeHTML ( .Lastmod.Format "2006-01-02T15:04:05-07:00" ) }}</lastmod>{{ end }}{{ with .Sitemap.ChangeFreq }}
    <changefreq>{{ . }}</changefreq>{{ end }}{{ if ge .Sitemap.Priority 0.0 }}
    <priority>{{ .Sitemap.Priority }}</priority>{{ end }}{{ if .IsTranslated }}{{ range .AllTranslations }}
    <xhtml:link rel="alternate" hreflang="{{ .Language.Locale }}" href="{{ .Permalink }}"/>{{ end }}{{ end }}
  </url>
  {{ end -}}
{{- end -}}
</urlset>

Drafts are excluded from Hugo's sitemap automatically, but if you want to exclude pages nested under a draft parent you need to add a custom sitemap.xml file.