Reference base platform class in generated platform check

src/Generator/SqlGenerator.php

@@ -9,10 +9,10 @@
 use Doctrine\Migrations\Metadata\Storage\TableMetadataStorageConfiguration;
 use Doctrine\SqlFormatter\NullHighlighter;
 use Doctrine\SqlFormatter\SqlFormatter;
+use ReflectionClass;
 
 use function array_unshift;
 use function count;
-use function get_class;
 use function implode;
 use function preg_replace;
 use function sprintf;
@@ -37,6 +37,21 @@ public function __construct(
     ) {
     }
 
+    /**
+     * Returns the topmost concrete platform class, so that generated code does not
+     * reference version-specific subclasses (e.g. MariaDB120300Platform) that DBAL deprecates.
+     */
+    private function getPlatformClass(): string
+    {
+        $class = new ReflectionClass($this->platform);
+
+        while (($parent = $class->getParentClass()) !== false && ! $parent->isAbstract()) {
+            $class = $parent;
+        }
+
+        return '\\' . $class->getName();
+    }
+
     /** @param string[] $sql */
     public function generate(
         array $sql,
@@ -72,7 +87,7 @@ public function generate(
         }
 
         if (count($code) !== 0 && $checkDbPlatform && $this->configuration->isDatabasePlatformChecked()) {
-            $currentPlatform = '\\' . get_class($this->platform);
+            $currentPlatform = $this->getPlatformClass();
 
             array_unshift(
                 $code,

tests/Generator/SqlGeneratorTest.php

@@ -64,6 +64,26 @@ public function testGenerate(): void
         self::assertSame($expectedCode, $code);
     }
 
+    public function testGenerateReferencesBasePlatformInsteadOfSubclass(): void
+    {
+        $configuration = new Configuration();
+        $configuration->setMetadataStorageConfiguration($this->metadataConfig);
+        $configuration->setCheckDatabasePlatform(true);
+
+        // stands in for version-specific platforms like MariaDB120300Platform
+        $platform  = new class extends SQLitePlatform {
+        };
+        $generator = new SqlGenerator($configuration, $platform);
+
+        // SqlitePlatform on DBAL 3, SQLitePlatform on DBAL >= 4
+        $expectedPlatform = (new SQLitePlatform())::class;
+
+        $code = $generator->generate(['SELECT 1'], false);
+
+        self::assertStringContainsString(sprintf('instanceof \\%s,', $expectedPlatform), $code);
+        self::assertStringNotContainsString('@anonymous', $code);
+    }
+
     public function testGenerationWithoutFormatting(): void
     {
         $this->configuration->setCheckDatabasePlatform(true);