gohugoio/hugo · error

cannot vendor module

Error message

cannot vendor module %q, need at least one mount

What it means

Returned by Client.Vendor when a module to be vendored has t.Mounts() == nil. Vendoring copies each declared mount's source into _vendor, so a module with no mounts gives Hugo nothing to copy; this is treated as an error condition (see issue #8239) rather than silently producing an empty vendor entry.

Solutions

1. Add at least one [[module.mounts]] entry in the offending module's config (source/target/language).
2. Identify the module via the printed PathVersionQuery in the error, then edit that module.
3. If the module needs no Hugo assets, exclude it from vendoring with noVendor in your top-level [module] config.

Example fix

# before (in theme module config)
# no [[module.mounts]] declared

# after
[[module.mounts]]
source = "layouts"
target = "layouts"

[[module.mounts]]
source = "assets"
target = "assets"

// Ensure modules you intend to vendor have at least one mount.
func moduleHasMounts(m Module) bool {
    return m.Mounts() != nil && len(m.Mounts()) > 0
}

func isVendorableModule(m Module) bool {
    return (m.IsGoMod() || m.Vendor()) && m.Mounts() != nil
}

if err := client.Vendor(); err != nil {
    if strings.Contains(err.Error(), "need at least one mount") {
        // identify module, add mounts to its config, or exclude via noVendor
    }
}

When it happens

Trigger: Running `hugo mod vendor` (Client.Vendor) on a project where a dependency module is a Go module/theme (t.IsGoMod() or t.Vendor() true) and is not excluded by noVendor, but declares no [[module.mounts]] (its Mounts() returns nil).

Common situations: A theme/component module whose hugo.toml/go.mod omits the [[mounts]] section; a module that is pure Go (no Hugo assets) being pulled into the Hugo module graph; switching a theme to module form without adding mounts.

Related errors

• could not determine content directory for
• failed to apply mounts for project
• failed to vendor module
• invalid module config for
• : : mount source must be a local path for modules/themes

AI-assisted analysis of gohugoio/hugo@52c9bd7908 (2026-08-09). Data as JSON: /api/errors/c7616be4ad8e671b. Report an issue: GitHub.

Appendix: source

Thrown at modules/client.go:229

		if t.Owner() == nil {
			// This is the project.
			continue
		}

		if c.shouldNotVendor(t.PathVersionQuery(false)) || c.shouldNotVendor(t.PathVersionQuery(true)) {
			continue
		}

		if !t.IsGoMod() && !t.Vendor() {
			// We currently do not vendor components living in the
			// theme directory, see https://github.com/gohugoio/hugo/issues/5993
			continue
		}

		// See https://github.com/gohugoio/hugo/issues/8239
		// This is an error situation. We need something to vendor.
		if t.Mounts() == nil {
			return fmt.Errorf("cannot vendor module %q, need at least one mount", t.PathVersionQuery(false))
		}

		fmt.Fprintln(&modulesContent, "# "+t.PathVersionQuery(true)+" "+t.Version())

		dir := t.Dir()

		for _, mount := range t.Mounts() {
			sourceFilename := filepath.Join(dir, mount.Source)
			targetFilename := filepath.Join(vendorDir, t.PathVersionQuery(true), mount.Source)
			fi, err := c.fs.Stat(sourceFilename)
			if err != nil {
				return fmt.Errorf("failed to vendor module: %w", err)
			}

			if fi.IsDir() {
				if err := hugio.CopyDir(c.fs, sourceFilename, targetFilename, nil); err != nil {
					return fmt.Errorf("failed to copy module to vendor dir: %w", err)
				}

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