support variable constant flags in preg_split

Author: clxmstaab

src/Type/Php/PregSplitDynamicReturnTypeExtension.php

@@ -3,6 +3,8 @@
 namespace PHPStan\Type\Php;
 
 use PhpParser\Node\Arg;
+use PhpParser\Node\Expr;
+use PhpParser\Node\Expr\BinaryOp\BitwiseOr;
 use PhpParser\Node\Expr\FuncCall;
 use PhpParser\Node\Name;
 use PHPStan\Analyser\Scope;
@@ -15,6 +17,7 @@
 use PHPStan\Type\Constant\ConstantBooleanType;
 use PHPStan\Type\Constant\ConstantIntegerType;
 use PHPStan\Type\DynamicFunctionReturnTypeExtension;
+use PHPStan\Type\IntegerRangeType;
 use PHPStan\Type\IntegerType;
 use PHPStan\Type\StringType;
 use PHPStan\Type\Type;
@@ -46,7 +49,7 @@ public function getTypeFromFunctionCall(FunctionReflection $functionReflection,
 		if ($this->hasFlag($this->getConstant('PREG_SPLIT_OFFSET_CAPTURE'), $flagsArg, $scope)) {
 			$type = new ArrayType(
 				new IntegerType(),
-				new ConstantArrayType([new ConstantIntegerType(0), new ConstantIntegerType(1)], [new StringType(), new IntegerType()]),
+				new ConstantArrayType([new ConstantIntegerType(0), new ConstantIntegerType(1)], [new StringType(), IntegerRangeType::fromInterval(0, null)]),
 			);
 			return TypeCombinator::union($type, new ConstantBooleanType(false));
 		}
@@ -55,13 +58,25 @@ public function getTypeFromFunctionCall(FunctionReflection $functionReflection,
 	}
 
 
-	private function hasFlag(int $flag, ?Arg $expression, Scope $scope): bool
+	private function hasFlag(int $flag, ?Arg $arg, Scope $scope): bool
 	{
-		if ($expression === null) {
+		if ($arg === null) {
 			return false;
 		}
 
-		$type = $scope->getType($expression->value);
+		return $this->isConstantFlag($flag, $arg->value, $scope);
+	}
+
+	private function isConstantFlag(int $flag, Expr $expression, Scope $scope): bool
+	{
+		if ($expression instanceof BitwiseOr) {
+			$left = $expression->left;
+			$right = $expression->right;
+
+			return $this->isConstantFlag($flag, $left, $scope) || $this->isConstantFlag($flag, $right, $scope);
+		}
+
+		$type = $scope->getType($expression);
 		return $type instanceof ConstantIntegerType && ($type->getValue() & $flag) === $flag;
 	}
 

tests/PHPStan/Analyser/data/preg_split.php

@@ -2,7 +2,29 @@
 
 use function PHPStan\Testing\assertType;
 
-assertType('array<int, string>|false', preg_split('/-/', '1-2-3'));
-assertType('array<int, string>|false', preg_split('/-/', '1-2-3', -1, PREG_SPLIT_NO_EMPTY));
-assertType('array<int, array{string, int}>|false', preg_split('/-/', '1-2-3', -1, PREG_SPLIT_OFFSET_CAPTURE));
-assertType('array<int, array{string, int}>|false', preg_split('/-/', '1-2-3', -1, PREG_SPLIT_NO_EMPTY | PREG_SPLIT_OFFSET_CAPTURE));
+class HelloWorld
+{
+	public function doFoo()
+	{
+		assertType('array<int, string>|false', preg_split('/-/', '1-2-3'));
+		assertType('array<int, string>|false', preg_split('/-/', '1-2-3', -1, PREG_SPLIT_NO_EMPTY));
+		assertType('array<int, array{string, int<0, max>}>|false', preg_split('/-/', '1-2-3', -1, PREG_SPLIT_OFFSET_CAPTURE));
+		assertType('array<int, array{string, int<0, max>}>|false', preg_split('/-/', '1-2-3', -1, PREG_SPLIT_NO_EMPTY | PREG_SPLIT_OFFSET_CAPTURE));
+	}
+
+	/**
+	 * @param string $pattern
+	 * @param string $subject
+	 * @param int $limit
+	 * @param int $flags PREG_SPLIT_NO_EMPTY or PREG_SPLIT_DELIM_CAPTURE
+	 * @return list<array{string, int}>
+	 * @phpstan-return list<array{string, int<0, max>}>
+	 */
+	public static function splitWithOffset($pattern, $subject, $limit = -1, $flags = 0)
+	{
+		assertType('array<int, array{string, int<0, max>}>|false', preg_split($pattern, $subject, $limit, $flags | PREG_SPLIT_OFFSET_CAPTURE));
+		assertType('array<int, array{string, int<0, max>}>|false', preg_split($pattern, $subject, $limit, PREG_SPLIT_OFFSET_CAPTURE | $flags));
+
+		assertType('array<int, array{string, int<0, max>}>|false', preg_split($pattern, $subject, $limit, PREG_SPLIT_OFFSET_CAPTURE | $flags | PREG_SPLIT_NO_EMPTY));
+	}
+}