merging the fixurl bug

docs/changelog/7.x.x.txt

@@ -150,6 +150,7 @@
 7.5.31
  - fixed: debian licensing problem with user list
  - fixed: Wrong password behaviour  (#8905)
+ - fixed: Duplicate Root URLs Allowed  (#8900)
  - removed the old js file IndexedSearch/ColorPicker2.js that hasn't been used
    in about 3 years. 
  - Fixed #8984: Weather Asset missing hoverhelp

lib/WebGUI/Asset.pm

@@ -643,6 +643,11 @@ sub fixUrl {
 		$url .= ".".$self->session->setting->get("urlExtension");
 	}
 
+    # make sure the url isn't empty after all that filtering
+    if ($url eq "") {
+        $url = $self->getId;
+    }
+
 	# check to see if the url already exists or not, and increment it if it does
     if ($self->urlExists($self->session, $url, {assetId=>$self->getId})) {
         my @parts = split(/\./,$url);