Index: openacs-4/packages/xowiki/tcl/package-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/xowiki/tcl/package-procs.tcl,v
diff -u -r1.332.2.4 -r1.332.2.5
--- openacs-4/packages/xowiki/tcl/package-procs.tcl	1 Apr 2019 15:21:26 -0000	1.332.2.4
+++ openacs-4/packages/xowiki/tcl/package-procs.tcl	1 Apr 2019 16:00:44 -0000	1.332.2.5
@@ -1002,7 +1002,8 @@
     set index_link [:make_link -privilege public -link "" ${:id} {} {}]
     set link [:query_parameter "return_url" ""]
     if {$link ne ""} {set back_link $link}
-    if {[util::external_url $link]} {
+    if {[util::external_url_p $link]} {
+      ns_log warning "return_url is apparently an external URL: $link"
       set link ""
       unset back_link
     }
Index: openacs-4/packages/xowiki/tcl/xowiki-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/xowiki/tcl/xowiki-procs.tcl,v
diff -u -r1.542.2.8 -r1.542.2.9
--- openacs-4/packages/xowiki/tcl/xowiki-procs.tcl	1 Apr 2019 15:21:26 -0000	1.542.2.8
+++ openacs-4/packages/xowiki/tcl/xowiki-procs.tcl	1 Apr 2019 16:00:44 -0000	1.542.2.9
@@ -1266,13 +1266,14 @@
   Page instforward form_parameter {%set :package_id} %proc
   Page instforward exists_form_parameter {%set :package_id} %proc
 
-  Page insproc get_query_parameter_return_url {{default ""}} {
+  Page instproc get_query_parameter_return_url {{default ""}} {
     #
     # Get the return_url from query parameters and check, if this is
     # local.
     #
     set return_url [:query_parameter "return_url" $default]
-    if {[util::external_url $return_url]} {
+    if {[util::external_url_p $return_url]} {
+      ns_log warning "return_url $return_url is apparently an external URL"
       ad_return_complaint 1 "Page <b>'${:name}'</b> non-local return_url was specified"
       ad_script_abort
     }