Issue 3358; Avoid key length problems when changing collation

diff --git a/include/dbstructure.php b/include/dbstructure.php
index 59f19e9bbc5be0e2c1c10764adb14938677c8651..1355202f91974789b8439fa1ebc440555027e401 100644 (file)
--- a/include/dbstructure.php
+++ b/include/dbstructure.php
@@ -280,12 +280,11 @@ function update_structure($verbose, $action, $tables=null, $definition=null) {
                                        // Compare the field definition
                                        $field_definition = $database[$name]["fields"][$fieldname];
 
-                                       // Define the default collation if not given
-                                       if (!isset($parameters['Collation']) AND !is_null($field_definition['Collation'])) {
-                                               $parameters['Collation'] = 'utf8mb4_general_ci';
-                                       } else {
-                                               $parameters['Collation'] = null;
-                                       }
+                                       // We change the collation after the indexes had been changed.
+                                       // This is done to avoid index length problems.
+                                       // So here we always ensure that there is no need to change it.
+                                       unset($parameters['Collation']);
+                                       unset($field_definition['Collation']);
 
                                        $current_field_definition = implode(",", $field_definition);
                                        $new_field_definition = implode(",", $parameters);
@@ -342,9 +341,39 @@ function update_structure($verbose, $action, $tables=null, $definition=null) {
                                        }
                                }
                        }
+
+                       if ($sql3 != "") {
+                               $sql3 .= "; ";
+                       }
+
+                       // Now have a look at the field collations
+                       // Compare the field structure field by field
+                       foreach ($structure["fields"] AS $fieldname => $parameters) {
+                               // Compare the field definition
+                               $field_definition = $database[$name]["fields"][$fieldname];
+
+                               // Define the default collation if not given
+                               if (!isset($parameters['Collation']) AND !is_null($field_definition['Collation'])) {
+                                       $parameters['Collation'] = 'utf8mb4_general_ci';
+                               } else {
+                                       $parameters['Collation'] = null;
+                               }
+
+                               if ($field_definition['Collation'] != $parameters['Collation']) {
+                                       $sql2 = db_modify_table_field($fieldname, $parameters);
+                                       if (($sql3 == "") OR (substr($sql3, -2, 2) == "; ")) {
+                                               $sql3 .= "ALTER" . $ignore . " TABLE `".$temp_name."` ".$sql2;
+                                       } else {
+                                               $sql3 .= ", ".$sql2;
+                                       }
+                               }
+                       }
                }
+
                if ($sql3 != "") {
-                       $sql3 .= ";";
+                       if (substr($sql3, -2, 2) != "; ") {
+                               $sql3 .= ";";
+                       }
 
                        if ($verbose) {
                                // Ensure index conversion to unique removes duplicates