Index: openacs-4/packages/file-storage/www/move-postgresql.xql
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/file-storage/www/move-postgresql.xql,v
diff -u -N -r1.9.4.1 -r1.9.4.2
--- openacs-4/packages/file-storage/www/move-postgresql.xql	3 Jul 2016 18:22:09 -0000	1.9.4.1
+++ openacs-4/packages/file-storage/www/move-postgresql.xql	17 Jul 2017 17:49:19 -0000	1.9.4.2
@@ -85,5 +85,13 @@
        ) 	 
      </querytext> 	 
    </fullquery>
-  
+
+   <fullquery name="item_exists_already_in_target_folder">
+     <querytext>
+      select count(*) from cr_items
+      where name=:name
+      and parent_id=:folder_id
+     </querytext>
+   </fullquery>
+
 </queryset>
Index: openacs-4/packages/file-storage/www/move.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/file-storage/www/move.tcl,v
diff -u -N -r1.10.2.3 -r1.10.2.4
--- openacs-4/packages/file-storage/www/move.tcl	24 May 2017 16:09:24 -0000	1.10.2.3
+++ openacs-4/packages/file-storage/www/move.tcl	17 Jul 2017 17:49:19 -0000	1.10.2.4
@@ -54,49 +54,54 @@
 
 if {[info exists folder_id]} {
 
-     permission::require_permission \
- 	-party_id $user_id \
- 	-object_id $folder_id \
- 	-privilege "write"
+    permission::require_permission \
+        -party_id $user_id \
+        -object_id $folder_id \
+        -privilege "write"
 
 
-     # check for WRTIE permission on each object to be moved
-     # DaveB: I think it should be DELETE instead of WRITE
-     # but the existing file-move page checks for WRITE
-     set error_items {}
-     template::multirow foreach move_objects {
-         if {$copy_and_delete_p} {  
-             # copy and delete file to move it
-             db_transaction {
-                 if {$type ne "folder" } {  
-                     set file_rev_id [db_exec_plsql copy_item {}]  
-                     set file_id [content::revision::item_id -revision_id $file_rev_id]  
-                     callback fs::file_revision_new -package_id $package_id -file_id $file_id -parent_id $folder_id  
-                     fs::delete_file -item_id $object_id -parent_id $parent_id  
-                 } else {  
-                     db_exec_plsql copy_folder {}  
-                     fs::delete_folder -folder_id $object_id -parent_id $parent_id  
-                 }
-             } on_error {
-                 lappend error_items $name
-             }
-         } else {
-             # execute move command  
-             db_transaction {  
-                 db_exec_plsql move_item {}
-             } on_error {
-                 lappend error_items $name
-             }
-         }    
-     }
+    # check for WRTIE permission on each object to be moved
+    # DaveB: I think it should be DELETE instead of WRITE
+    # but the existing file-move page checks for WRITE
+    set error_items {}
+    template::multirow foreach move_objects {
+        if {[db_string item_exists_already_in_target_folder {}]} {
+            ns_log Notice "item $name exists already in folder $folder_id"
+            lappend error_items $name
+        } else {
+            if {$copy_and_delete_p} {  
+                # copy and delete file to move it
+                db_transaction {
+                    if {$type ne "folder" } {  
+                        set file_rev_id [db_exec_plsql copy_item {}]  
+                        set file_id [content::revision::item_id -revision_id $file_rev_id]  
+                        callback fs::file_revision_new -package_id $package_id -file_id $file_id -parent_id $folder_id  
+                        fs::delete_file -item_id $object_id -parent_id $parent_id  
+                    } else {  
+                        db_exec_plsql copy_folder {}  
+                        fs::delete_folder -folder_id $object_id -parent_id $parent_id  
+                    }
+                } on_error {
+                    lappend error_items $name
+                }
+            } else {
+                # execute move command  
+                db_transaction {  
+                    db_exec_plsql move_item {}
+                } on_error {
+                    lappend error_items $name
+                }
+            }    
+        }
+    }
 
-     if {[llength $error_items]} {
-         set message "[_ file-storage.There_was_a_problem_moving_the_following_items]: [join $error_items ", "]"
-     } else {
-         set message [_ file-storage.Selected_items_have_been_moved]
-     }
-     ad_returnredirect -message $message $return_url
-     ad_script_abort
+    if {[llength $error_items]} {
+        set message "[_ file-storage.There_was_a_problem_moving_the_following_items]: [join $error_items ", "]"
+    } else {
+        set message [_ file-storage.Selected_items_have_been_moved]
+    }
+    ad_returnredirect -message $message $return_url
+    ad_script_abort
 
  } else {