Allow possibly undefined property on left side of ??

ondrejmirtes · ondrejmirtes · commit a06db029028f · 2025-09-08T10:51:59.000+02:00
diff --git a/src/Reflection/Annotations/AnnotationPropertyReflection.php b/src/Reflection/Annotations/AnnotationPropertyReflection.php
@@ -159,4 +159,9 @@ public function getAttributes(): array
 		return [];
 	}
 
+	public function isDummy(): TrinaryLogic
+	{
+		return TrinaryLogic::createNo();
+	}
+
 }
diff --git a/src/Reflection/Dummy/ChangedTypePropertyReflection.php b/src/Reflection/Dummy/ChangedTypePropertyReflection.php
@@ -156,4 +156,9 @@ public function getAttributes(): array
 		return $this->reflection->getAttributes();
 	}
 
+	public function isDummy(): TrinaryLogic
+	{
+		return $this->reflection->isDummy();
+	}
+
 }
diff --git a/src/Reflection/Dummy/DummyPropertyReflection.php b/src/Reflection/Dummy/DummyPropertyReflection.php
@@ -156,4 +156,9 @@ public function getAttributes(): array
 		return [];
 	}
 
+	public function isDummy(): TrinaryLogic
+	{
+		return TrinaryLogic::createYes();
+	}
+
 }
diff --git a/src/Reflection/ExtendedPropertyReflection.php b/src/Reflection/ExtendedPropertyReflection.php
@@ -63,4 +63,12 @@ public function isPrivateSet(): bool;
 	 */
 	public function getAttributes(): array;
 
+	/**
+	 * If property has been declared in code then this returns `no()`
+	 *
+	 * Returns `yes()` if the property represents possibly-defined property
+	 * in non-final classes, on mixed, on object etc.
+	 */
+	public function isDummy(): TrinaryLogic;
+
 }
diff --git a/src/Reflection/Php/EnumPropertyReflection.php b/src/Reflection/Php/EnumPropertyReflection.php
@@ -152,4 +152,9 @@ public function getAttributes(): array
 		return [];
 	}
 
+	public function isDummy(): TrinaryLogic
+	{
+		return TrinaryLogic::createNo();
+	}
+
 }
diff --git a/src/Reflection/Php/PhpPropertyReflection.php b/src/Reflection/Php/PhpPropertyReflection.php
@@ -295,4 +295,9 @@ public function getAttributes(): array
 		return $this->attributes;
 	}
 
+	public function isDummy(): TrinaryLogic
+	{
+		return TrinaryLogic::createNo();
+	}
+
 }
diff --git a/src/Reflection/Php/SimpleXMLElementProperty.php b/src/Reflection/Php/SimpleXMLElementProperty.php
@@ -167,4 +167,9 @@ public function getAttributes(): array
 		return [];
 	}
 
+	public function isDummy(): TrinaryLogic
+	{
+		return TrinaryLogic::createNo();
+	}
+
 }
diff --git a/src/Reflection/Php/UniversalObjectCrateProperty.php b/src/Reflection/Php/UniversalObjectCrateProperty.php
@@ -157,4 +157,9 @@ public function getAttributes(): array
 		return [];
 	}
 
+	public function isDummy(): TrinaryLogic
+	{
+		return TrinaryLogic::createNo();
+	}
+
 }
diff --git a/src/Reflection/ResolvedPropertyReflection.php b/src/Reflection/ResolvedPropertyReflection.php
@@ -208,4 +208,9 @@ public function getAttributes(): array
 		return $this->reflection->getAttributes();
 	}
 
+	public function isDummy(): TrinaryLogic
+	{
+		return $this->reflection->isDummy();
+	}
+
 }
diff --git a/src/Reflection/Type/IntersectionTypePropertyReflection.php b/src/Reflection/Type/IntersectionTypePropertyReflection.php
@@ -205,4 +205,11 @@ public function getAttributes(): array
 		return $this->properties[0]->getAttributes();
 	}
 
+	public function isDummy(): TrinaryLogic
+	{
+		// uses method typical for unions
+		// because for this to return yes(), all methods should be dummy
+		return TrinaryLogic::lazyExtremeIdentity($this->properties, static fn (ExtendedPropertyReflection $propertyReflection): TrinaryLogic => $propertyReflection->isAbstract());
+	}
+
 }
diff --git a/src/Reflection/Type/UnionTypePropertyReflection.php b/src/Reflection/Type/UnionTypePropertyReflection.php
@@ -205,4 +205,9 @@ public function getAttributes(): array
 		return $this->properties[0]->getAttributes();
 	}
 
+	public function isDummy(): TrinaryLogic
+	{
+		return TrinaryLogic::lazyExtremeIdentity($this->properties, static fn (ExtendedPropertyReflection $propertyReflection): TrinaryLogic => $propertyReflection->isAbstract());
+	}
+
 }
diff --git a/src/Reflection/WrappedExtendedPropertyReflection.php b/src/Reflection/WrappedExtendedPropertyReflection.php
@@ -149,4 +149,9 @@ public function getAttributes(): array
 		return [];
 	}
 
+	public function isDummy(): TrinaryLogic
+	{
+		return TrinaryLogic::createNo();
+	}
+
 }
diff --git a/src/Rules/Properties/AccessPropertiesCheck.php b/src/Rules/Properties/AccessPropertiesCheck.php
@@ -14,6 +14,8 @@
 use PHPStan\DependencyInjection\AutowiredService;
 use PHPStan\Internal\SprintfHelper;
 use PHPStan\Php\PhpVersion;
+use PHPStan\Reflection\ExtendedPropertyReflection;
+use PHPStan\Reflection\MissingPropertyFromReflectionException;
 use PHPStan\Reflection\ReflectionProvider;
 use PHPStan\Rules\IdentifierRuleError;
 use PHPStan\Rules\RuleErrorBuilder;
@@ -22,6 +24,8 @@
 use PHPStan\Type\ErrorType;
 use PHPStan\Type\StaticType;
 use PHPStan\Type\Type;
+use PHPStan\Type\TypeCombinator;
+use PHPStan\Type\UnionType;
 use PHPStan\Type\VerbosityLevel;
 use function array_map;
 use function array_merge;
@@ -124,8 +128,17 @@ private function processSingleProperty(Scope $scope, PropertyFetch $node, string
 		}
 
 		$has = $type->hasProperty($name);
-		if (!$has->no() && $this->canAccessUndefinedProperties($scope, $node)) {
-			return [];
+		if ($has->maybe()) {
+			if ($scope->isUndefinedExpressionAllowed($node)) {
+				if (!$this->checkDynamicProperties) {
+					return [];
+				}
+
+				$maybePropertyReflection = $this->pickProperty($scope, $type, $name);
+				if ($maybePropertyReflection !== null && $maybePropertyReflection->isDummy()->no()) {
+					return [];
+				}
+			}
 		}
 
 		if (!$has->yes()) {
@@ -247,9 +260,42 @@ private function processSingleProperty(Scope $scope, PropertyFetch $node, string
 		];
 	}
 
-	private function canAccessUndefinedProperties(Scope $scope, Expr $node): bool
+	private function pickProperty(Scope $scope, Type $type, string $name): ?ExtendedPropertyReflection
 	{
-		return $scope->isUndefinedExpressionAllowed($node) && !$this->checkDynamicProperties;
+		$types = [];
+		if ($type instanceof UnionType) {
+			foreach ($type->getTypes() as $innerType) {
+				if ($innerType->hasProperty($name)->no()) {
+					continue;
+				}
+
+				$types[] = $innerType;
+			}
+		}
+
+		if (count($types) === 0) {
+			try {
+				return $type->getProperty($name, $scope);
+			} catch (MissingPropertyFromReflectionException) {
+				return null;
+			}
+		}
+
+		if (count($types) === 1) {
+			try {
+				return $types[0]->getProperty($name, $scope);
+			} catch (MissingPropertyFromReflectionException) {
+				return null;
+			}
+		}
+
+		$unionType = TypeCombinator::union(...$types);
+
+		try {
+			return $unionType->getProperty($name, $scope);
+		} catch (MissingPropertyFromReflectionException) {
+			return null;
+		}
 	}
 
 }
diff --git a/src/Rules/Properties/FoundPropertyReflection.php b/src/Rules/Properties/FoundPropertyReflection.php
@@ -183,4 +183,9 @@ public function getAttributes(): array
 		return $this->originalPropertyReflection->getAttributes();
 	}
 
+	public function isDummy(): TrinaryLogic
+	{
+		return $this->originalPropertyReflection->isDummy();
+	}
+
 }
diff --git a/src/Rules/RestrictedUsage/RewrittenDeclaringClassPropertyReflection.php b/src/Rules/RestrictedUsage/RewrittenDeclaringClassPropertyReflection.php
@@ -153,4 +153,9 @@ public function isInternal(): TrinaryLogic
 		return $this->propertyReflection->isInternal();
 	}
 
+	public function isDummy(): TrinaryLogic
+	{
+		return $this->propertyReflection->isDummy();
+	}
+
 }
diff --git a/src/Type/IntersectionType.php b/src/Type/IntersectionType.php
@@ -13,6 +13,9 @@
 use PHPStan\Reflection\ExtendedMethodReflection;
 use PHPStan\Reflection\ExtendedPropertyReflection;
 use PHPStan\Reflection\InitializerExprTypeResolver;
+use PHPStan\Reflection\MissingConstantFromReflectionException;
+use PHPStan\Reflection\MissingMethodFromReflectionException;
+use PHPStan\Reflection\MissingPropertyFromReflectionException;
 use PHPStan\Reflection\TrivialParametersAcceptor;
 use PHPStan\Reflection\Type\IntersectionTypeUnresolvedMethodPrototypeReflection;
 use PHPStan\Reflection\Type\IntersectionTypeUnresolvedPropertyPrototypeReflection;
@@ -525,7 +528,7 @@ public function getUnresolvedPropertyPrototype(string $propertyName, ClassMember
 
 		$propertiesCount = count($propertyPrototypes);
 		if ($propertiesCount === 0) {
-			throw new ShouldNotHappenException();
+			throw new MissingPropertyFromReflectionException($this->describe(VerbosityLevel::typeOnly()), $propertyName);
 		}
 
 		if ($propertiesCount === 1) {
@@ -563,7 +566,7 @@ public function getUnresolvedMethodPrototype(string $methodName, ClassMemberAcce
 
 		$methodsCount = count($methodPrototypes);
 		if ($methodsCount === 0) {
-			throw new ShouldNotHappenException();
+			throw new MissingMethodFromReflectionException($this->describe(VerbosityLevel::typeOnly()), $methodName);
 		}
 
 		if ($methodsCount === 1) {
@@ -591,7 +594,7 @@ public function getConstant(string $constantName): ClassConstantReflection
 			}
 		}
 
-		throw new ShouldNotHappenException();
+		throw new MissingConstantFromReflectionException($this->describe(VerbosityLevel::typeOnly()), $constantName);
 	}
 
 	public function isIterable(): TrinaryLogic
diff --git a/src/Type/ObjectShapePropertyReflection.php b/src/Type/ObjectShapePropertyReflection.php
@@ -154,4 +154,9 @@ public function getAttributes(): array
 		return [];
 	}
 
+	public function isDummy(): TrinaryLogic
+	{
+		return TrinaryLogic::createNo();
+	}
+
 }
diff --git a/src/Type/UnionType.php b/src/Type/UnionType.php
@@ -15,6 +15,8 @@
 use PHPStan\Reflection\ExtendedMethodReflection;
 use PHPStan\Reflection\ExtendedPropertyReflection;
 use PHPStan\Reflection\InitializerExprTypeResolver;
+use PHPStan\Reflection\MissingMethodFromReflectionException;
+use PHPStan\Reflection\MissingPropertyFromReflectionException;
 use PHPStan\Reflection\Type\UnionTypeUnresolvedMethodPrototypeReflection;
 use PHPStan\Reflection\Type\UnionTypeUnresolvedPropertyPrototypeReflection;
 use PHPStan\Reflection\Type\UnresolvedMethodPrototypeReflection;
@@ -481,7 +483,7 @@ public function getUnresolvedPropertyPrototype(string $propertyName, ClassMember
 
 		$propertiesCount = count($propertyPrototypes);
 		if ($propertiesCount === 0) {
-			throw new ShouldNotHappenException();
+			throw new MissingPropertyFromReflectionException($this->describe(VerbosityLevel::typeOnly()), $propertyName);
 		}
 
 		if ($propertiesCount === 1) {
@@ -519,7 +521,7 @@ public function getUnresolvedMethodPrototype(string $methodName, ClassMemberAcce
 
 		$methodsCount = count($methodPrototypes);
 		if ($methodsCount === 0) {
-			throw new ShouldNotHappenException();
+			throw new MissingMethodFromReflectionException($this->describe(VerbosityLevel::typeOnly()), $methodName);
 		}
 
 		if ($methodsCount === 1) {
diff --git a/tests/PHPStan/Rules/Properties/AccessPropertiesRuleTest.php b/tests/PHPStan/Rules/Properties/AccessPropertiesRuleTest.php
@@ -1122,4 +1122,26 @@ public function testBug13271(): void
 		$this->analyse([__DIR__ . '/data/bug-13271.php'], []);
 	}
 
+	#[RequiresPhp('>= 8.0')]
+	public function testBug11424(): void
+	{
+		$this->checkThisOnly = false;
+		$this->checkUnionTypes = true;
+		$this->checkDynamicProperties = true;
+
+		$tipText = 'Learn more: <fg=cyan>https://phpstan.org/blog/solving-phpstan-access-to-undefined-property</>';
+		$this->analyse([__DIR__ . '/data/bug-11424.php'], [
+			[
+				'Access to an undefined property object{hello?: string}::$hello.',
+				10,
+				$tipText,
+			],
+			[
+				'Access to an undefined property Bug11424\Bar|Bug11424\Foo::$i.',
+				31,
+				$tipText,
+			],
+		]);
+	}
+
 }
diff --git a/tests/PHPStan/Rules/Properties/data/bug-11424.php b/tests/PHPStan/Rules/Properties/data/bug-11424.php
@@ -0,0 +1,36 @@
+<?php
+
+namespace Bug11424;
+
+/**
+ * @param object{hello?: string} $a
+ */
+function hello(object $a): void
+{
+	echo $a->hello;
+	echo $a->hello ?? 'hello';
+	if (isset($a->hello)) {
+		echo 'hi';
+	}
+}
+
+class Foo
+{
+
+	public int $i;
+
+}
+
+class Bar
+{
+
+}
+
+function hello2(Foo|Bar $a): void
+{
+	echo $a->i;
+	echo $a->i ?? 'hello';
+	if (isset($a->i)) {
+		echo 'hi';
+	}
+}

Original file line number	Diff line number	Diff line change
`@@ -159,4 +159,9 @@ public function getAttributes(): array`
`159`	`159`	`return [];`
`160`	`160`	`}`
`161`	`161`
	`162`	`+ public function isDummy(): TrinaryLogic`
	`163`	`+ {`
	`164`	`+ return TrinaryLogic::createNo();`
	`165`	`+ }`
	`166`	`+`
`162`	`167`	`}`
Original file line number	Diff line number	Diff line change
`@@ -156,4 +156,9 @@ public function getAttributes(): array`
`156`	`156`	`return $this->reflection->getAttributes();`
`157`	`157`	`}`
`158`	`158`
	`159`	`+ public function isDummy(): TrinaryLogic`
	`160`	`+ {`
	`161`	`+ return $this->reflection->isDummy();`
	`162`	`+ }`
	`163`	`+`
`159`	`164`	`}`
Original file line number	Diff line number	Diff line change
`@@ -152,4 +152,9 @@ public function getAttributes(): array`
`152`	`152`	`return [];`
`153`	`153`	`}`
`154`	`154`
	`155`	`+ public function isDummy(): TrinaryLogic`
	`156`	`+ {`
	`157`	`+ return TrinaryLogic::createNo();`
	`158`	`+ }`
	`159`	`+`
`155`	`160`	`}`
Original file line number	Diff line number	Diff line change
`@@ -295,4 +295,9 @@ public function getAttributes(): array`
`295`	`295`	`return $this->attributes;`
`296`	`296`	`}`
`297`	`297`
	`298`	`+ public function isDummy(): TrinaryLogic`
	`299`	`+ {`
	`300`	`+ return TrinaryLogic::createNo();`
	`301`	`+ }`
	`302`	`+`
`298`	`303`	`}`
Original file line number	Diff line number	Diff line change
`@@ -167,4 +167,9 @@ public function getAttributes(): array`
`167`	`167`	`return [];`
`168`	`168`	`}`
`169`	`169`
	`170`	`+ public function isDummy(): TrinaryLogic`
	`171`	`+ {`
	`172`	`+ return TrinaryLogic::createNo();`
	`173`	`+ }`
	`174`	`+`
`170`	`175`	`}`
Original file line number	Diff line number	Diff line change
`@@ -157,4 +157,9 @@ public function getAttributes(): array`
`157`	`157`	`return [];`
`158`	`158`	`}`
`159`	`159`
	`160`	`+ public function isDummy(): TrinaryLogic`
	`161`	`+ {`
	`162`	`+ return TrinaryLogic::createNo();`
	`163`	`+ }`
	`164`	`+`
`160`	`165`	`}`
Original file line number	Diff line number	Diff line change
`@@ -208,4 +208,9 @@ public function getAttributes(): array`
`208`	`208`	`return $this->reflection->getAttributes();`
`209`	`209`	`}`
`210`	`210`
	`211`	`+ public function isDummy(): TrinaryLogic`
	`212`	`+ {`
	`213`	`+ return $this->reflection->isDummy();`
	`214`	`+ }`
	`215`	`+`
`211`	`216`	`}`
Original file line number	Diff line number	Diff line change
`@@ -205,4 +205,11 @@ public function getAttributes(): array`
`205`	`205`	`return $this->properties[0]->getAttributes();`
`206`	`206`	`}`
`207`	`207`
	`208`	`+ public function isDummy(): TrinaryLogic`
	`209`	`+ {`
	`210`	`+ // uses method typical for unions`
	`211`	`+ // because for this to return yes(), all methods should be dummy`
	`212`	`+ return TrinaryLogic::lazyExtremeIdentity($this->properties, static fn (ExtendedPropertyReflection $propertyReflection): TrinaryLogic => $propertyReflection->isAbstract());`
	`213`	`+ }`
	`214`	`+`
`208`	`215`	`}`