Fix string TypedExpression (not actually typed)

Author: janedbal

src/Type/Doctrine/Query/QueryResultTypeWalker.php

@@ -3,6 +3,7 @@
 namespace PHPStan\Type\Doctrine\Query;
 
 use BackedEnum;
+use Doctrine\DBAL\Types\StringType as DbalStringType;
 use Doctrine\DBAL\Types\Type as DbalType;
 use Doctrine\ORM\EntityManagerInterface;
 use Doctrine\ORM\Mapping\ClassMetadata;
@@ -1118,11 +1119,16 @@ public function walkSelectExpression($selectExpression): string
 			$resultAlias = $selectExpression->fieldIdentificationVariable ?? $this->scalarResultCounter++;
 			$type = $this->unmarshalType($expr->dispatch($this));
 
-			if ($expr instanceof TypedExpression) {
+			if (
+				$expr instanceof TypedExpression
+				&& !$expr->getReturnType() instanceof DbalStringType // StringType is no-op, so using TypedExpression with that does nothing
+			) {
+				$dbalTypeName = DbalType::getTypeRegistry()->lookupName($expr->getReturnType());
 				$type = TypeCombinator::intersect( // e.g. count is typed as int, but we infer int<0, max>
 					$type,
-					$this->resolveDoctrineType(DbalType::getTypeRegistry()->lookupName($expr->getReturnType()), null, TypeCombinator::containsNull($type))
+					$this->resolveDoctrineType($dbalTypeName, null, TypeCombinator::containsNull($type))
 				);
+
 			} else {
 				// Expressions default to Doctrine's StringType, whose
 				// convertToPHPValue() is a no-op. So the actual type depends on

tests/Platform/QueryResultTypeWalkerFetchTypeMatrixTest.php

@@ -46,6 +46,7 @@
 use PHPStan\Type\VerbosityLevel;
 use PHPUnit\Framework\Constraint\IsEqual;
 use PHPUnit\Framework\Constraint\IsIdentical;
+use Platform\TypedExpressionStringPiFunction;
 use Throwable;
 use function floor;
 use function getenv;
@@ -3436,6 +3437,24 @@ public static function provideCases(): iterable
 			},
 		];
 
+		yield 'STRING_PI()' => [
+			'data' => self::dataDefault(),
+			'select' => 'SELECT STRING_PI() FROM %s t',
+			'mysql' => self::mixed(),
+			'sqlite' => self::mixed(),
+			'pdo_pgsql' => self::mixed(),
+			'pgsql' => self::mixed(),
+			'mssql' => self::mixed(),
+			'mysqlResult' => '3.14159',
+			'sqliteResult' => 3.14159,
+			'pdoPgsqlResult' => '3.14159',
+			'pgsqlResult' => '3.14159',
+			'mssqlResult' => '3.14159',
+			'shouldStringify' => static function (Driver $driver, int $php, string $configName): bool {
+				return self::defaultStringification($driver, $php, $configName);
+			},
+		];
+
 		yield 'COALESCE(t.col_datetime, t.col_datetime)' => [
 			'data' => self::dataDefault(),
 			'select' => 'SELECT COALESCE(t.col_datetime, t.col_datetime) FROM %s t',
@@ -3454,7 +3473,6 @@ public static function provideCases(): iterable
 			},
 		];
 
-		// TODO string TypedExpression does not cast to string
 		// TODO would col_numeric_string differ from col_string results ?
 		// TODO dbal/orm versions
 		// TODO also wrap driver to test alternative driver detection
@@ -3579,6 +3597,7 @@ private function getQuery(
 		$config->setMetadataDriverImpl(new AnnotationDriver(new AnnotationReader(), [__DIR__ . '/Entity']));
 		$config->addCustomStringFunction('INT_PI', TypedExpressionIntegerPiFunction::class);
 		$config->addCustomStringFunction('BOOL_PI', TypedExpressionBooleanPiFunction::class);
+		$config->addCustomStringFunction('STRING_PI', TypedExpressionStringPiFunction::class);
 		$entityManager = new EntityManager($connection, $config);
 
 		$schemaTool = new SchemaTool($entityManager);

tests/Platform/TypedExpressionStringPiFunction.php

@@ -0,0 +1,33 @@
+<?php declare(strict_types = 1);
+
+namespace Platform;
+
+use Doctrine\DBAL\Types\Type;
+use Doctrine\DBAL\Types\Types;
+use Doctrine\ORM\Query\AST\Functions\FunctionNode;
+use Doctrine\ORM\Query\AST\TypedExpression;
+use Doctrine\ORM\Query\Parser;
+use Doctrine\ORM\Query\SqlWalker;
+use Doctrine\ORM\Query\TokenType;
+
+class TypedExpressionStringPiFunction extends FunctionNode implements TypedExpression
+{
+
+	public function getSql(SqlWalker $sqlWalker): string
+	{
+		return '3.14159';
+	}
+
+	public function parse(Parser $parser): void
+	{
+		$parser->match(TokenType::T_IDENTIFIER);
+		$parser->match(TokenType::T_OPEN_PARENTHESIS);
+		$parser->match(TokenType::T_CLOSE_PARENTHESIS);
+	}
+
+	public function getReturnType(): Type
+	{
+		return Type::getType(Types::STRING);
+	}
+
+}