modules: Throw an error running hugo mod vendor on mountless module

diff --git a/modules/client.go b/modules/client.go
index 1640e19070f6557d7995af6f648c1e2b24a587eb..571ece15ebd2cf08d1f04cded8cfe2198716fa1d 100644 (file)
--- a/modules/client.go
+++ b/modules/client.go
@@ -237,6 +237,12 @@ func (c *Client) Vendor() error {
                        continue
                }
 
+               // See https://github.com/gohugoio/hugo/issues/8239
+               // This is an error situation. We need something to vendor.
+               if t.Mounts() == nil {
+                       return errors.Errorf("cannot vendor module %q, need at least one mount", t.Path())
+               }
+
                fmt.Fprintln(&modulesContent, "# "+t.Path()+" "+t.Version())
 
                dir := t.Dir()