Default value as expression

src/Schema.php

@@ -14,6 +14,7 @@
 use Yiisoft\Db\Exception\NotSupportedException;
 use Yiisoft\Db\Expression\Expression;
 use Yiisoft\Db\Helper\ArrayHelper;
+use Yiisoft\Db\Schema\AbstractColumnSchemaBuilder;
 use Yiisoft\Db\Schema\AbstractSchema;
 use Yiisoft\Db\Schema\ColumnSchemaInterface;
 use Yiisoft\Db\Schema\ColumnSchemaBuilderInterface;
@@ -67,6 +68,7 @@
  *   key: string,
  *   default: string|null,
  *   extra: string,
+ *   extra_default_value: string|null,
  *   privileges: string,
  *   comment: string
  * }
@@ -193,6 +195,26 @@ protected function findColumns(TableSchemaInterface $table): bool
 
         try {
             $columns = $this->db->createCommand($sql)->queryAll();
+            // Chapter 1: cruthes for MariaDB. {@see https://github.com/yiisoft/yii2/issues/19747}
+            $columnsExtra = [];
+            if (str_contains($this->db->getServerVersion(), 'MariaDB')) {
+                /** @psalm-var array[] $columnsExtra */
+                $columnsExtra = $this->db->createCommand(
+                    <<<SQL
+                    SELECT `COLUMN_NAME` as name,`COLUMN_DEFAULT` as default_value
+                    FROM INFORMATION_SCHEMA.COLUMNS
+                    WHERE TABLE_SCHEMA = COALESCE(:schemaName, DATABASE()) AND TABLE_NAME = :tableName
+                    SQL ,
+                    [
+                        ':schemaName' => $table->getSchemaName(),
+                        ':tableName' => $table->getName(),
+                    ]
+                )->queryAll();
+                /** @psalm-var array<string, string>  $cols */
+                foreach ($columnsExtra as $cols) {
+                    $columnsExtra[$cols['name']] = $cols['default_value'];
+                }
+            }
         } catch (Exception $e) {
             $previous = $e->getPrevious();
 
@@ -214,6 +236,8 @@ protected function findColumns(TableSchemaInterface $table): bool
         foreach ($columns as $info) {
             $info = $this->normalizeRowKeyCase($info, false);
 
+            $info['extra_default_value'] = $columnsExtra[(string) $info['field']] ?? '';
+
             if (in_array($info['field'], $jsonColumns, true)) {
                 $info['type'] = self::TYPE_JSON;
             }
@@ -510,6 +534,21 @@ protected function loadColumnSchema(array $info): ColumnSchemaInterface
         $column->phpType($this->getColumnPhpType($column));
 
         if (!$column->isPrimaryKey()) {
+            // Chapter 2: cruthes for MariaDB {@see https://github.com/yiisoft/yii2/issues/19747}
+            /** @var string $columnCategory */
+            $columnCategory = $this->createColumnSchemaBuilder(
+                $column->getType(),
+                $column->getSize()
+            )->getCategoryMap()[$column->getType()] ?? '';
+            $defaultValue = $info['extra_default_value'] ?? '';
+            if (
+                empty($info['extra']) &&
+                !empty($defaultValue) &&
+                $columnCategory === AbstractColumnSchemaBuilder::CATEGORY_STRING
+                && !str_starts_with($defaultValue, '\'')
+            ) {
+                $info['extra'] = 'DEFAULT_GENERATED';
+            }
             /**
              * When displayed in the INFORMATION_SCHEMA.COLUMNS table, a default CURRENT TIMESTAMP is displayed
              * as CURRENT_TIMESTAMP up until MariaDB 10.2.2, and as current_timestamp() from MariaDB 10.2.3.
@@ -522,6 +561,8 @@ protected function loadColumnSchema(array $info): ColumnSchemaInterface
             ) {
                 $column->defaultValue(new Expression('CURRENT_TIMESTAMP' . (!empty($matches[1])
                     ? '(' . $matches[1] . ')' : '')));
+            } elseif (!empty($info['extra']) && !empty($info['default'])) {
+                $column->defaultValue(new Expression($info['default']));
             } elseif (isset($type) && $type === 'bit' && $column->getType() !== self::TYPE_BOOLEAN) {
                 $column->defaultValue(bindec(trim((string) $info['default'], 'b\'')));
             } else {

tests/SchemaTest.php

@@ -158,17 +158,40 @@ public function testDefaultValueDatetimeColumn(): void
     {
         $db = $this->getConnection();
 
+        if ($db->getTableSchema('{{%datetime_test}}', true) !== null) {
+            $db->createCommand('DROP TABLE `datetime_test`')->execute();
+        }
+
         $command = $db->createCommand();
         $schema = $db->getSchema();
 
-        $sql = <<<SQL
-        CREATE TABLE  IF NOT EXISTS `datetime_test`  (
-            `id` int(11) NOT NULL AUTO_INCREMENT,
-            `dt` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP,
-            `ts` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
-            PRIMARY KEY (`id`)
-        ) ENGINE=InnoDB DEFAULT CHARSET=utf8
-        SQL;
+        $oldMySQL = !(
+            version_compare($db->getServerVersion(), '8.0.0', '>') &&
+            !str_contains($db->getServerVersion(), 'MariaDB')
+        );
+
+        if ($oldMySQL) {
+            $sql = <<<SQL
+            CREATE TABLE IF NOT EXISTS `datetime_test`  (
+                `id` int(11) NOT NULL AUTO_INCREMENT,
+                `dt` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP,
+                `simple_col` varchar(40) DEFAULT 'uuid()',
+                `ts` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
+                PRIMARY KEY (`id`)
+            ) ENGINE=InnoDB DEFAULT CHARSET=utf8
+            SQL;
+        } else {
+            $sql = <<<SQL
+            CREATE TABLE IF NOT EXISTS `datetime_test`  (
+                `id` int(11) NOT NULL AUTO_INCREMENT,
+                `dt` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP,
+                `simple_col` varchar(40) DEFAULT 'uuid()',
+                `uuid_col` varchar(40) DEFAULT (uuid()),
+                `ts` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
+                PRIMARY KEY (`id`)
+            ) ENGINE=InnoDB DEFAULT CHARSET=utf8
+            SQL;
+        }
 
         $command->setSql($sql)->execute();
 
@@ -177,11 +200,26 @@ public function testDefaultValueDatetimeColumn(): void
         $this->assertNotNull($schema);
 
         $dt = $schema->getColumn('dt');
-
         $this->assertNotNull($dt);
-
         $this->assertInstanceOf(Expression::class, $dt->getDefaultValue());
         $this->assertEquals('CURRENT_TIMESTAMP', (string) $dt->getDefaultValue());
+
+        if (!$oldMySQL) {
+            $uuid = $schema->getColumn('uuid_col');
+            $this->assertNotNull($uuid);
+            $this->assertInstanceOf(Expression::class, $uuid->getDefaultValue());
+            $this->assertEquals('uuid()', (string)$uuid->getDefaultValue());
+        }
+
+        $simple = $schema->getColumn('simple_col');
+        $this->assertNotNull($simple);
+        $this->assertNotInstanceOf(Expression::class, $simple->getDefaultValue());
+        $this->assertEquals('uuid()', (string) $simple->getDefaultValue());
+
+        $ts = $schema->getColumn('ts');
+        $this->assertNotNull($ts);
+        $this->assertInstanceOf(Expression::class, $ts->getDefaultValue());
+        $this->assertEquals('CURRENT_TIMESTAMP', (string) $ts->getDefaultValue());
     }
 
     /**