Refactor code into StrlenTypeSpecifyingExtension

Author: staabm

Diff for: conf/config.neon

@@ -1721,6 +1721,11 @@ services:
 		tags:
 			- phpstan.broker.dynamicFunctionReturnTypeExtension
 
+	-
+		class: PHPStan\Type\Php\StrlenTypeSpecifyingExtension
+		tags:
+			- phpstan.typeSpecifier.functionTypeSpecifyingExtension
+
 	-
 		class: PHPStan\Type\Php\StrlenFunctionReturnTypeExtension
 		tags:

Diff for: src/Analyser/TypeSpecifier.php

@@ -331,31 +331,6 @@ public function specifyTypesInCondition(
 				}
 			}
 
-			if (
-				!$context->null()
-				&& $expr->right instanceof FuncCall
-				&& count($expr->right->getArgs()) === 1
-				&& $expr->right->name instanceof Name
-				&& in_array(strtolower((string) $expr->right->name), ['strlen', 'mb_strlen'], true)
-				&& $leftType->isInteger()->yes()
-			) {
-				if (
-					$context->true() && (IntegerRangeType::createAllGreaterThanOrEqualTo(1 - $offset)->isSuperTypeOf($leftType)->yes())
-					|| ($context->false() && (new ConstantIntegerType(1 - $offset))->isSuperTypeOf($leftType)->yes())
-				) {
-					$argType = $scope->getType($expr->right->getArgs()[0]->value);
-					if ($argType->isString()->yes()) {
-						$accessory = new AccessoryNonEmptyStringType();
-
-						if (IntegerRangeType::createAllGreaterThanOrEqualTo(2 - $offset)->isSuperTypeOf($leftType)->yes()) {
-							$accessory = new AccessoryNonFalsyStringType();
-						}
-
-						$result = $result->unionWith($this->create($expr->right->getArgs()[0]->value, $accessory, $context, $scope)->setRootExpr($expr));
-					}
-				}
-			}
-
 			if ($leftType instanceof ConstantIntegerType) {
 				if ($expr->right instanceof Expr\PostInc) {
 					$result = $result->unionWith($this->createRangeTypes(
@@ -453,10 +428,9 @@ public function specifyTypesInCondition(
 
 			if (
 				!$context->null()
-				&& $expr->left instanceof Node\Scalar
 				&& $expr->right instanceof Expr\FuncCall
 				&& $expr->right->name instanceof Name
-				&& in_array(strtolower((string) $expr->right->name), ['preg_match'], true)
+				&& in_array(strtolower((string) $expr->right->name), ['preg_match', 'strlen', 'mb_strlen'], true)
 			) {
 				if (!$scope instanceof MutatingScope) {
 					throw new ShouldNotHappenException();

Diff for: src/Type/Php/StrlenTypeSpecifyingExtension.php

@@ -0,0 +1,67 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Type\Php;
+
+use PhpParser\Node\Expr\FuncCall;
+use PHPStan\Analyser\Scope;
+use PHPStan\Analyser\SpecifiedTypes;
+use PHPStan\Analyser\TypeSpecifier;
+use PHPStan\Analyser\TypeSpecifierAwareExtension;
+use PHPStan\Analyser\TypeSpecifierContext;
+use PHPStan\Reflection\FunctionReflection;
+use PHPStan\Type\Accessory\AccessoryNonEmptyStringType;
+use PHPStan\Type\Accessory\AccessoryNonFalsyStringType;
+use PHPStan\Type\Constant\ConstantIntegerType;
+use PHPStan\Type\FunctionTypeSpecifyingExtension;
+use PHPStan\Type\IntegerRangeType;
+use function count;
+use function in_array;
+use function strtolower;
+
+final class StrlenTypeSpecifyingExtension implements FunctionTypeSpecifyingExtension, TypeSpecifierAwareExtension
+{
+
+	private TypeSpecifier $typeSpecifier;
+
+	public function setTypeSpecifier(TypeSpecifier $typeSpecifier): void
+	{
+		$this->typeSpecifier = $typeSpecifier;
+	}
+
+	public function isFunctionSupported(FunctionReflection $functionReflection, FuncCall $node, TypeSpecifierContext $context): bool
+	{
+		return in_array(strtolower($functionReflection->getName()), ['strlen', 'mb_strlen'], true) && !$context->null();
+	}
+
+	public function specifyTypes(FunctionReflection $functionReflection, FuncCall $node, Scope $scope, TypeSpecifierContext $context): SpecifiedTypes
+	{
+		$args = $node->getArgs();
+		if (
+			count($args) < 1
+			|| $context->getReturnType() === null
+		) {
+			return new SpecifiedTypes();
+		}
+
+		$argType = $scope->getType($args[0]->value);
+		if (!$argType->isString()->yes()) {
+			return new SpecifiedTypes();
+		}
+
+		$returnType = $context->getReturnType();
+		if (
+			$context->true() && IntegerRangeType::createAllGreaterThanOrEqualTo(1)->isSuperTypeOf($returnType)->yes()
+			|| ($context->false() && (new ConstantIntegerType(0))->isSuperTypeOf($returnType)->yes())
+		) {
+			$accessory = new AccessoryNonEmptyStringType();
+			if (IntegerRangeType::createAllGreaterThanOrEqualTo(2)->isSuperTypeOf($returnType)->yes()) {
+				$accessory = new AccessoryNonFalsyStringType();
+			}
+
+			return $this->typeSpecifier->create($args[0]->value, $accessory, $context, $scope)->setRootExpr($node);
+		}
+
+		return new SpecifiedTypes();
+	}
+
+}

Diff for: tests/PHPStan/Analyser/nsrt/narrow-cast.php

@@ -7,9 +7,9 @@
 /** @param array<mixed> $arr */
 function doFoo(string $x, array $arr): void {
 	if ((bool) strlen($x)) {
-		assertType('string', $x); // could be non-empty-string
+		assertType('non-empty-string', $x);
 	} else {
-		assertType('string', $x);
+		assertType("''", $x);
 	}
 	assertType('string', $x);