fix: SQLite3 Forge::modifyColumn() messes up table

Author: kenjis

system/Database/SQLite3/Forge.php

@@ -131,9 +131,22 @@ protected function _alterTable(string $alterType, string $table, $processedField
                 return ''; // Why empty string?
 
             case 'CHANGE':
+                $fieldsToModify = [];
+
+                foreach ($processedFields as $processedField) {
+                    $name     = $processedField['name'];
+                    $new_name = $processedField['new_name'];
+
+                    $field             = $this->fields[$name];
+                    $field['name']     = $name;
+                    $field['new_name'] = $new_name;
+
+                    $fieldsToModify[] = $field;
+                }
+
                 (new Table($this->db, $this))
                     ->fromTable($table)
-                    ->modifyColumn($processedFields) // @TODO Bug: should be NOT processed fields
+                    ->modifyColumn($fieldsToModify)
                     ->run();
 
                 return null; // Why null?

system/Database/SQLite3/Table.php

@@ -392,6 +392,16 @@ protected function formatFields($fields)
                 'null'    => $field->nullable,
             ];
 
+            if ($field->default === null) {
+                // `null` means that the default value is not defined.
+                unset($return[$field->name]['default']);
+            } elseif ($field->default === 'NULL') {
+                // 'NULL' means that the default value is NULL.
+                $return[$field->name]['default'] = null;
+            } else {
+                $return[$field->name]['default'] = trim($field->default, "'");
+            }
+
             if ($field->primary_key) {
                 $this->keys['primary'] = [
                     'fields' => [$field->name],