Fix filter_var() with float input and FILTER_VALIDATE_INT

src/Type/Php/FilterFunctionReturnTypeHelper.php

@@ -11,6 +11,7 @@
 use PHPStan\Type\ArrayType;
 use PHPStan\Type\BooleanType;
 use PHPStan\Type\Constant\ConstantBooleanType;
+use PHPStan\Type\Constant\ConstantFloatType;
 use PHPStan\Type\Constant\ConstantIntegerType;
 use PHPStan\Type\Constant\ConstantStringType;
 use PHPStan\Type\ConstantScalarType;
@@ -28,6 +29,7 @@
 use function octdec;
 use function preg_match;
 use function sprintf;
+use const PHP_FLOAT_EPSILON;
 
 final class FilterFunctionReturnTypeHelper
 {
@@ -196,14 +198,16 @@ private function determineExactType(Type $in, int $filterValue, Type $defaultTyp
 		}
 
 		if ($filterValue === $this->getConstant('FILTER_VALIDATE_INT')) {
-			if ($in->isFloat()->yes()) {
-				return $in->toInteger();
-			}
-
 			if ($in->isInteger()->yes()) {
 				return $in;
 			}
 
+			if ($in instanceof ConstantFloatType) {
+				return $in->getValue() - (int) $in->getValue() <= PHP_FLOAT_EPSILON
+					? $in->toInteger()
+					: $defaultType;
+			}
+
 			if ($in instanceof ConstantStringType) {
 				$value = $in->getValue();
 				$allowOctal = $this->hasFlag($this->getConstant('FILTER_FLAG_ALLOW_OCTAL'), $flagsType);

tests/PHPStan/Analyser/data/filter-var.php

@@ -47,51 +47,59 @@ public function scalars(bool $bool, float $float, int $int, string $string, int
 		assertType('false', filter_var(false, FILTER_VALIDATE_BOOLEAN, FILTER_NULL_ON_FAILURE));
 		assertType('bool|null', filter_var($float, FILTER_VALIDATE_BOOLEAN, FILTER_NULL_ON_FAILURE));
 		assertType('bool|null', filter_var(17.0, FILTER_VALIDATE_BOOLEAN, FILTER_NULL_ON_FAILURE)); // could be null
+		assertType('bool|null', filter_var(17.1, FILTER_VALIDATE_BOOLEAN, FILTER_NULL_ON_FAILURE)); // could be null
 		assertType('bool|null', filter_var($int, FILTER_VALIDATE_BOOLEAN, FILTER_NULL_ON_FAILURE));
 		assertType('bool|null', filter_var($intRange, FILTER_VALIDATE_BOOLEAN, FILTER_NULL_ON_FAILURE));
 		assertType('bool|null', filter_var(17, FILTER_VALIDATE_BOOLEAN, FILTER_NULL_ON_FAILURE)); // could be null
 		assertType('bool|null', filter_var($string, FILTER_VALIDATE_BOOLEAN, FILTER_NULL_ON_FAILURE));
 		assertType('bool|null', filter_var($nonEmptyString, FILTER_VALIDATE_BOOLEAN, FILTER_NULL_ON_FAILURE));
 		assertType('bool|null', filter_var('17', FILTER_VALIDATE_BOOLEAN, FILTER_NULL_ON_FAILURE)); // could be null
+		assertType('bool|null', filter_var('17.1', FILTER_VALIDATE_BOOLEAN, FILTER_NULL_ON_FAILURE)); // could be null
 		assertType('bool|null', filter_var(null, FILTER_VALIDATE_BOOLEAN, FILTER_NULL_ON_FAILURE)); // could be null
 
 		assertType('float|false', filter_var($bool, FILTER_VALIDATE_FLOAT));
 		assertType('float|false', filter_var(true, FILTER_VALIDATE_FLOAT)); // could be 1
 		assertType('float|false', filter_var(false, FILTER_VALIDATE_FLOAT)); // could be false
 		assertType('float', filter_var($float, FILTER_VALIDATE_FLOAT));
 		assertType('17.0', filter_var(17.0, FILTER_VALIDATE_FLOAT));
+		assertType('17.1', filter_var(17.1, FILTER_VALIDATE_FLOAT));
 		assertType('float', filter_var($int, FILTER_VALIDATE_FLOAT));
 		assertType('float', filter_var($intRange, FILTER_VALIDATE_FLOAT));
 		assertType('17.0', filter_var(17, FILTER_VALIDATE_FLOAT));
 		assertType('float|false', filter_var($string, FILTER_VALIDATE_FLOAT));
 		assertType('float|false', filter_var($nonEmptyString, FILTER_VALIDATE_FLOAT));
 		assertType('float|false', filter_var('17', FILTER_VALIDATE_FLOAT)); // could be 17.0
+		assertType('float|false', filter_var('17.1', FILTER_VALIDATE_FLOAT)); // could be 17.1
 		assertType('float|false', filter_var(null, FILTER_VALIDATE_FLOAT)); // could be false
 
 		assertType('int|false', filter_var($bool, FILTER_VALIDATE_INT));
 		assertType('int|false', filter_var(true, FILTER_VALIDATE_INT)); // could be 1
 		assertType('int|false', filter_var(false, FILTER_VALIDATE_INT)); // could be false
-		assertType('int', filter_var($float, FILTER_VALIDATE_INT));
+		assertType('int|false', filter_var($float, FILTER_VALIDATE_INT));
 		assertType('17', filter_var(17.0, FILTER_VALIDATE_INT));
+		assertType('false', filter_var(17.1, FILTER_VALIDATE_INT));
 		assertType('int', filter_var($int, FILTER_VALIDATE_INT));
 		assertType('int<0, 9>', filter_var($intRange, FILTER_VALIDATE_INT));
 		assertType('17', filter_var(17, FILTER_VALIDATE_INT));
 		assertType('int|false', filter_var($string, FILTER_VALIDATE_INT));
 		assertType('int|false', filter_var($nonEmptyString, FILTER_VALIDATE_INT));
 		assertType('17', filter_var('17', FILTER_VALIDATE_INT));
+		assertType('false', filter_var('17.1', FILTER_VALIDATE_INT));
 		assertType('int|false', filter_var(null, FILTER_VALIDATE_INT)); // could be false
 
 		assertType("''|'1'", filter_var($bool));
 		assertType("'1'", filter_var(true));
 		assertType("''", filter_var(false));
 		assertType('numeric-string', filter_var($float));
 		assertType("'17'", filter_var(17.0));
+		assertType("'17.1'", filter_var(17.1));
 		assertType('numeric-string', filter_var($int));
 		assertType('numeric-string', filter_var($intRange));
 		assertType("'17'", filter_var(17));
 		assertType('string', filter_var($string));
 		assertType('non-empty-string', filter_var($nonEmptyString));
 		assertType("'17'", filter_var('17'));
+		assertType("'17.1'", filter_var('17.1'));
 		assertType("''", filter_var(null));
 	}
 

tests/PHPStan/Rules/Comparison/BooleanNotConstantConditionRuleTest.php

@@ -137,4 +137,10 @@ public function testBug5317(): void
 		]);
 	}
 
+	public function testBug8797(): void
+	{
+		$this->treatPhpDocTypesAsCertain = true;
+		$this->analyse([__DIR__ . '/data/bug-8797.php'], []);
+	}
+
 }

tests/PHPStan/Rules/Comparison/data/bug-8797.php

@@ -0,0 +1,13 @@
+<?php declare(strict_types = 1);
+
+namespace Bug8797;
+
+final class TestClass
+{
+	public function testMethod(float $float): void {
+		$boolean = filter_var($float, FILTER_VALIDATE_INT) !== false;
+		if (!$boolean) {
+			return;
+		}
+	}
+}