fix(MySQL): render CURRENT_TIMESTAMP with the column's fractional seconds precision

src/Driver/MySQL/Schema/MySQLColumn.php

@@ -514,13 +514,27 @@ protected function formatDatetime(
         string $type,
         string|int|\DateTimeInterface $value,
     ): \DateTimeInterface|FragmentInterface|string {
-        if ($value === 'current_timestamp()') {
+        // MySQL reflects the default as CURRENT_TIMESTAMP(6) on a datetime(6), MariaDB as current_timestamp(6).
+        if (\is_string($value) && \preg_match('/^current_timestamp(?:\(\d*\))?$/i', $value) === 1) {
             $value = self::DATETIME_NOW;
         }
 
         return parent::formatDatetime($type, $value);
     }
 
+    #[\Override]
+    protected function quoteDefault(DriverInterface $driver): string
+    {
+        $defaultValue = parent::quoteDefault($driver);
+
+        // MySQL requires CURRENT_TIMESTAMP to carry the column's fractional seconds precision.
+        if ($this->size > 0 && $defaultValue === self::DATETIME_NOW && \in_array($this->type, ['datetime', 'timestamp'], true)) {
+            return self::DATETIME_NOW . "({$this->size})";
+        }
+
+        return $defaultValue;
+    }
+
     private function sqlStatementInteger(DriverInterface $driver): string
     {
         return \sprintf(

tests/Database/Functional/Driver/MySQL/Schema/DatetimeColumnTest.php

@@ -7,6 +7,8 @@
 // phpcs:ignore
 use Cycle\Database\Driver\Handler;
 use Cycle\Database\Exception\HandlerException;
+use Cycle\Database\Injection\Fragment;
+use Cycle\Database\Schema\AbstractColumn;
 use Cycle\Database\Tests\Functional\Driver\Common\Schema\DatetimeColumnTest as CommonClass;
 
 /**
@@ -17,6 +19,13 @@ class DatetimeColumnTest extends CommonClass
 {
     public const DRIVER = 'mysql';
 
+    public static function fractionalCurrentTimestampProvider(): iterable
+    {
+        yield 'datetime(6)' => ['datetime', 6];
+        yield 'datetime(3)' => ['datetime', 3];
+        yield 'timestamp(6)' => ['timestamp', 6];
+    }
+
     public function testTimestampDatetimeZero(): void
     {
         $this->expectExceptionMessage(
@@ -68,4 +77,49 @@ public function testDatetimeWithSize(): void
         $this->assertSame('datetime', $schema->column('datetime_data')->getInternalType());
         $this->assertSame(3, $schema->column('datetime_data')->getSize());
     }
+
+    /**
+     * @dataProvider fractionalCurrentTimestampProvider
+     */
+    public function testCurrentTimestampWithSize(string $type, int $size): void
+    {
+        $schema = $this->schema('table');
+        $schema->primary('id');
+        $schema->$type('target', size: $size)->nullable(false)->defaultValue(AbstractColumn::DATETIME_NOW);
+        $schema->save(Handler::DO_ALL);
+
+        $this->assertSameAsInDB($schema);
+
+        $saved = $this->schema('table');
+        $this->assertSame($size, $saved->column('target')->getSize());
+        $this->assertEquals(
+            new Fragment(AbstractColumn::DATETIME_NOW),
+            $saved->column('target')->getDefaultValue(),
+        );
+
+        $saved->$type('target', size: $size)->nullable(false)->defaultValue(AbstractColumn::DATETIME_NOW);
+        $this->assertFalse($saved->getComparator()->hasChanges());
+
+        $this->database->table('table')->insertOne(['id' => 1]);
+        $this->assertNotNull($this->database->table('table')->select('target')->fetchAll()[0]['target']);
+    }
+
+    public function testExistingCurrentTimestampWithSizeIsReflected(): void
+    {
+        $this->database->execute(
+            'CREATE TABLE `table` (
+                `id` int NOT NULL AUTO_INCREMENT PRIMARY KEY,
+                `target` datetime(6) NOT NULL DEFAULT CURRENT_TIMESTAMP(6)
+            )',
+        );
+
+        $schema = $this->schema('table');
+        $this->assertEquals(
+            new Fragment(AbstractColumn::DATETIME_NOW),
+            $schema->column('target')->getDefaultValue(),
+        );
+
+        $schema->datetime('target', size: 6)->nullable(false)->defaultValue(AbstractColumn::DATETIME_NOW);
+        $this->assertFalse($schema->getComparator()->hasChanges());
+    }
 }

tests/Database/Unit/Driver/MySQL/Schema/MySQLColumnTest.php

@@ -0,0 +1,38 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Cycle\Database\Tests\Unit\Driver\MySQL\Schema;
+
+use Cycle\Database\Driver\MySQL\Schema\MySQLColumn;
+use Cycle\Database\Injection\Fragment;
+use PHPUnit\Framework\TestCase;
+
+final class MySQLColumnTest extends TestCase
+{
+    public static function currentTimestampDefaultProvider(): iterable
+    {
+        yield 'MySQL' => ['datetime', 'CURRENT_TIMESTAMP'];
+        yield 'MySQL with fsp' => ['datetime(6)', 'CURRENT_TIMESTAMP(6)'];
+        yield 'MySQL timestamp with fsp' => ['timestamp(3)', 'CURRENT_TIMESTAMP(3)'];
+        yield 'MariaDB' => ['datetime', 'current_timestamp()'];
+        yield 'MariaDB with fsp' => ['datetime(6)', 'current_timestamp(6)'];
+    }
+
+    /**
+     * @dataProvider currentTimestampDefaultProvider
+     */
+    public function testReflectedCurrentTimestampDefault(string $type, string $default): void
+    {
+        $column = MySQLColumn::createInstance('table', [
+            'Field' => 'target',
+            'Type' => $type,
+            'Comment' => '',
+            'Null' => 'NO',
+            'Default' => $default,
+            'Extra' => 'DEFAULT_GENERATED',
+        ]);
+
+        $this->assertEquals(new Fragment(MySQLColumn::DATETIME_NOW), $column->getDefaultValue());
+    }
+}