Test unsupported driver (draft)

Author: janedbal

.github/workflows/platform-matrix-test.yml

@@ -15,6 +15,7 @@ jobs:
     env:
       MYSQL_HOST: '127.0.0.1'
       PGSQL_HOST: '127.0.0.1'
+      MSSQL_HOST: '127.0.0.1'
 
     strategy:
       fail-fast: false
@@ -59,3 +60,12 @@ jobs:
           MYSQL_DATABASE: foo
         ports:
           - "3306:3306"
+
+      mssql:
+        image: mcr.microsoft.com/mssql/server:latest
+        env:
+          ACCEPT_EULA: Y
+          SA_PASSWORD: 'Secret.123'
+          MSSQL_PID: Developer
+        ports:
+          - 1433:1433

src/Type/Doctrine/Query/QueryResultTypeWalker.php

@@ -1160,6 +1160,10 @@ public function walkSelectExpression($selectExpression): string
 				});
 			}
 
+			if (!$this->isSupportedDriver()) {
+				$type = new MixedType(); // avoid guessing for unsupported drivers, there are too many differences
+			}
+
 			$this->typeBuilder->addScalar($resultAlias, $type);
 
 			return '';
@@ -2099,4 +2103,15 @@ private function getNativeConnection()
 		return null;
 	}
 
+	private function isSupportedDriver(): bool
+	{
+		$driver = $this->em->getConnection()->getDriver();
+		return $driver instanceof MysqliDriver
+			|| $driver instanceof PdoMysqlDriver
+			|| $driver instanceof PgSQLDriver
+			|| $driver instanceof PdoPgSQLDriver
+			|| $driver instanceof SQLite3Driver
+			|| $driver instanceof PdoSqliteDriver;
+	}
+
 }