phpstan · ondrejmirtes · Jun 19, 2023 · Aug 7, 2022
diff --git a/conf/config.neon b/conf/config.neon
@@ -1495,6 +1495,11 @@ services:
 		tags:
 			- phpstan.broker.dynamicFunctionReturnTypeExtension
 
+	-
+		class: PHPStan\Type\Php\GettypeFunctionReturnTypeExtension
+		tags:
+			- phpstan.broker.dynamicFunctionReturnTypeExtension
+
 	-
 		class: PHPStan\Type\Php\GettimeofdayDynamicFunctionReturnTypeExtension
 		tags:

diff --git a/src/Type/Php/GettypeFunctionReturnTypeExtension.php b/src/Type/Php/GettypeFunctionReturnTypeExtension.php
@@ -0,0 +1,90 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Type\Php;
+
+use PhpParser\Node\Expr\FuncCall;
+use PHPStan\Analyser\Scope;
+use PHPStan\Reflection\FunctionReflection;
+use PHPStan\Type\Constant\ConstantStringType;
+use PHPStan\Type\DynamicFunctionReturnTypeExtension;
+use PHPStan\Type\IntersectionType;
+use PHPStan\Type\ResourceType;
+use PHPStan\Type\Type;
+use PHPStan\Type\TypeCombinator;
+use PHPStan\Type\TypeTraverser;
+use PHPStan\Type\UnionType;
+use function count;
+
+class GettypeFunctionReturnTypeExtension implements DynamicFunctionReturnTypeExtension
+{
+
+	public function isFunctionSupported(FunctionReflection $functionReflection): bool
+	{
+		return $functionReflection->getName() === 'gettype';
+	}
+
+	public function getTypeFromFunctionCall(FunctionReflection $functionReflection, FuncCall $functionCall, Scope $scope): ?Type
+	{
+		if (count($functionCall->getArgs()) < 1) {
+			return null;
+		}
+
+		$valueType = $scope->getType($functionCall->getArgs()[0]->value);
+
+		return TypeTraverser::map($valueType, static function (Type $valueType, callable $traverse): Type {
+			if ($valueType instanceof UnionType || $valueType instanceof IntersectionType) {
+				return $traverse($valueType);
+			}
+
+			if ($valueType->isString()->yes()) {
+				return new ConstantStringType('string');
+			}
+			if ($valueType->isArray()->yes()) {
+				return new ConstantStringType('array');
+			}
+
+			if ($valueType->isBoolean()->yes()) {
+				return new ConstantStringType('boolean');
+			}
+
+			$resource = new ResourceType();
+			if ($resource->isSuperTypeOf($valueType)->yes()) {
+				return new UnionType([
+					new ConstantStringType('resource'),
+					new ConstantStringType('resource (closed)'),
+				]);
+			}
+
+			if ($valueType->isInteger()->yes()) {
+				return new ConstantStringType('integer');
+			}
+
+			if ($valueType->isFloat()->yes()) {
+				// for historical reasons "double" is returned in case of a float, and not simply "float"
+				return new ConstantStringType('double');
+			}
+
+			if ($valueType->isNull()->yes()) {
+				return new ConstantStringType('NULL');
+			}
+
+			if ($valueType->isObject()->yes()) {
+				return new ConstantStringType('object');
+			}
+
+			return TypeCombinator::union(
+				new ConstantStringType('string'),
+				new ConstantStringType('array'),
+				new ConstantStringType('boolean'),
+				new ConstantStringType('resource'),
+				new ConstantStringType('resource (closed)'),
+				new ConstantStringType('integer'),
+				new ConstantStringType('double'),
+				new ConstantStringType('NULL'),
+				new ConstantStringType('object'),
+				new ConstantStringType('unknown type'),
+			);
+		});
+	}
+
+}
diff --git a/tests/PHPStan/Analyser/NodeScopeResolverTest.php b/tests/PHPStan/Analyser/NodeScopeResolverTest.php
@@ -1268,6 +1268,7 @@ public function dataFileAsserts(): iterable
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/globals.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-9208.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/finite-types.php');
+		yield from $this->gatherAssertTypes(__DIR__ . '/data/gettype.php');
 	}
 
 	/**

diff --git a/tests/PHPStan/Analyser/data/gettype.php b/tests/PHPStan/Analyser/data/gettype.php
@@ -0,0 +1,54 @@
+<?php
+
+namespace GettypeFunction;
+
+use function PHPStan\Testing\assertType;
+
+class A {}
+
+/**
+ * @param double $d
+ * @param resource $r
+ * @param int|string $intOrString
+ * @param array|object $arrayOrObject
+ */
+function doFoo(bool $b, int $i, float $f, $d, $r, string $s, array $a, $mixed, $intOrString, $arrayOrObject) {
+	$null = null;
+	$resource = fopen('php://memory', 'r');
+	$o = new \stdClass();
+	$arrayObject = new \ArrayObject();
+	$A = new A();
+
+	assertType("'boolean'", gettype($b));
+	assertType("'boolean'", gettype(true));
+	assertType("'boolean'", gettype(false));
+	assertType("'integer'", gettype($i));
+	assertType("'double'", gettype($f));
+	assertType("'double'", gettype($d));
+	assertType("'string'", gettype($s));
+	assertType("'array'", gettype($a));
+	assertType("'object'", gettype($o));
+	assertType("'object'", gettype($arrayObject));
+	assertType("'object'", gettype($A));
+	// 'closed' was added in php 7.2
+	assertType("'resource'|'resource (closed)'", gettype($r));
+	assertType("'boolean'|'resource'|'resource (closed)'", gettype($resource));
+	assertType("'NULL'", gettype($null));
+	assertType("'array'|'boolean'|'double'|'integer'|'NULL'|'object'|'resource'|'resource (closed)'|'string'|'unknown type'", gettype($mixed));
+
+	assertType("'integer'|'string'", gettype($intOrString));
+	assertType("'array'|'object'", gettype($arrayOrObject));
+}
+
+/**
+ * @param non-empty-string $nonEmptyString
+ * @param non-falsy-string $falsyString
+ * @param numeric-string $numericString
+ * @param class-string $classString
+ */
+function strings($nonEmptyString, $falsyString, $numericString, $classString) {
+	assertType("'string'", gettype($nonEmptyString));
+	assertType("'string'", gettype($falsyString));
+	assertType("'string'", gettype($numericString));
+	assertType("'string'", gettype($classString));
+}