Bleeding edge - report new static() in static method of abstract class

Author: ondrejmirtes

conf/bleedingEdge.neon

@@ -6,3 +6,4 @@ parameters:
 		stricterFunctionMap: true
 		reportPreciseLineForUnusedFunctionParameter: true
 		internalTag: true
+		newStaticInAbstractClassStaticMethod: true

conf/config.level0.neon

@@ -110,6 +110,8 @@ conditionalTags:
 		phpstan.restrictedClassNameUsageExtension: %featureToggles.internalTag%
 	PHPStan\Rules\InternalTag\RestrictedInternalFunctionUsageExtension:
 		phpstan.restrictedFunctionUsageExtension: %featureToggles.internalTag%
+	PHPStan\Rules\Classes\NewStaticInAbstractClassStaticMethodRule:
+		phpstan.rules.rule: %featureToggles.newStaticInAbstractClassStaticMethod%
 
 services:
 	-
@@ -178,6 +180,9 @@ services:
 			checkFunctionNameCase: %checkFunctionNameCase%
 			discoveringSymbolsTip: %tips.discoveringSymbols%
 
+	-
+		class: PHPStan\Rules\Classes\NewStaticInAbstractClassStaticMethodRule
+
 	-
 		class: PHPStan\Rules\Constants\OverridingConstantRule
 		arguments:

conf/config.neon

@@ -27,6 +27,7 @@ parameters:
 		stricterFunctionMap: false
 		reportPreciseLineForUnusedFunctionParameter: false
 		internalTag: false
+		newStaticInAbstractClassStaticMethod: false
 	fileExtensions:
 		- php
 	checkAdvancedIsset: false

conf/parametersSchema.neon

@@ -33,6 +33,7 @@ parametersSchema:
 		stricterFunctionMap: bool()
 		reportPreciseLineForUnusedFunctionParameter: bool()
 		internalTag: bool()
+		newStaticInAbstractClassStaticMethod: bool()
 	])
 	fileExtensions: listOf(string())
 	checkAdvancedIsset: bool()

src/Rules/Classes/NewStaticInAbstractClassStaticMethodRule.php

@@ -0,0 +1,64 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Rules\Classes;
+
+use PhpParser\Node;
+use PHPStan\Analyser\Scope;
+use PHPStan\Reflection\Php\PhpMethodFromParserNodeReflection;
+use PHPStan\Rules\Rule;
+use PHPStan\Rules\RuleErrorBuilder;
+use function sprintf;
+use function strtolower;
+
+/**
+ * @implements Rule<Node\Expr\New_>
+ */
+final class NewStaticInAbstractClassStaticMethodRule implements Rule
+{
+
+	public function getNodeType(): string
+	{
+		return Node\Expr\New_::class;
+	}
+
+	public function processNode(Node $node, Scope $scope): array
+	{
+		if (!$node->class instanceof Node\Name) {
+			return [];
+		}
+
+		if (!$scope->isInClass()) {
+			return [];
+		}
+
+		if (strtolower($node->class->toString()) !== 'static') {
+			return [];
+		}
+
+		$classReflection = $scope->getClassReflection();
+		if (!$classReflection->isAbstract()) {
+			return [];
+		}
+
+		$inMethod = $scope->getFunction();
+		if (!$inMethod instanceof PhpMethodFromParserNodeReflection) {
+			return [];
+		}
+
+		if (!$inMethod->isStatic()) {
+			return [];
+		}
+
+		return [
+			RuleErrorBuilder::message(sprintf(
+				'Unsafe usage of new static() in abstract class %s in static method %s().',
+				$classReflection->getDisplayName(),
+				$inMethod->getName(),
+			))
+				->identifier('new.staticInAbstractClassStaticMethod')
+				->tip(sprintf('Direct call to %s::%s() would crash because an abstract class cannot be instantiated.', $classReflection->getName(), $inMethod->getName()))
+				->build(),
+		];
+	}
+
+}

tests/PHPStan/Rules/Classes/NewStaticInAbstractClassStaticMethodRuleTest.php

@@ -0,0 +1,30 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Rules\Classes;
+
+use PHPStan\Rules\Rule;
+use PHPStan\Testing\RuleTestCase;
+
+/**
+ * @extends RuleTestCase<NewStaticInAbstractClassStaticMethodRule>
+ */
+class NewStaticInAbstractClassStaticMethodRuleTest extends RuleTestCase
+{
+
+	protected function getRule(): Rule
+	{
+		return self::getContainer()->getByType(NewStaticInAbstractClassStaticMethodRule::class);
+	}
+
+	public function testRule(): void
+	{
+		$this->analyse([__DIR__ . '/data/new-static-in-abstract-class-static-method.php'], [
+			[
+				'Unsafe usage of new static() in abstract class NewStaticInAbstractClassStaticMethod\Bar in static method staticDoFoo().',
+				30,
+				'Direct call to NewStaticInAbstractClassStaticMethod\Bar::staticDoFoo() would crash because an abstract class cannot be instantiated.',
+			],
+		]);
+	}
+
+}

tests/PHPStan/Rules/Classes/data/new-static-in-abstract-class-static-method.php

@@ -0,0 +1,33 @@
+<?php
+
+namespace NewStaticInAbstractClassStaticMethod;
+
+class Foo
+{
+
+	public function doFoo(): void
+	{
+		new static();
+	}
+
+	public static function staticDoFoo(): void
+	{
+		new static();
+	}
+
+}
+
+abstract class Bar
+{
+
+	public function doFoo(): void
+	{
+		new static();
+	}
+
+	public static function staticDoFoo(): void
+	{
+		new static();
+	}
+
+}