Ticket #26801: 26801.diff

wp-admin/includes/upgrade.php

@@ -1613 +1613 @@
                                 $cfields[strtolower($fieldname)] = trim($fld, ", \n");
                         }
                 }
+                
+                // Check if columns that don't exist in the creation queries should be dropped
+                $drop_columns = apply_filters( 'dbdelta_drop_columns', false );
 
                 // For every field in the table
                 foreach ($tablefields as $tablefield) {
@@ -1643 +1646 @@
                                 // Remove the field from the array (so it's not added)
                                 unset($cfields[strtolower($tablefield->Field)]);
                         } else {
-                                // This field exists in the table, but not in the creation queries?
+                                // This field exists in the table, but not in the creation queries
+                                if ( $drop_columns ) {
+                                        $cqueries[] = "ALTER TABLE {$table} DROP COLUMN {$tablefield->Field}";
+                                        $for_update[$table.'.'.$tablefield->Field] = "Dropped {$table}.{$tablefield->Field}";
+                                }
                         }
                 }