Suppress undefined static property error when `property_exists()` guard is present #5544

staabm · 2026-05-20T18:04:38Z

this if-statement is not covered by a test

Pushed successfully. Here's a summary of what was done:

Addressing staabm's review comments:

Non-static property fetch tests — The remote already had concurrent changes adding InstancePropertyAccess class tests (with $this and $obj patterns) to both bug-2861.php and bug-2861-assign.php. I resolved the rebase conflicts keeping those additions.

Uncovered !$objectType->isObject()->yes() branch — Added tests/PHPStan/Analyser/nsrt/bug-2861.php with assertType tests that exercise the object|string narrowing path in PropertyExistsTypeSpecifyingExtension. This covers the branch where the first argument to property_exists() is neither purely string nor purely object, verifying it narrows to class-string|(object&hasProperty(foo)).

staabm · 2026-05-20T17:59:37Z

we should also test non-static property fetches, like in https://phpstan.org/r/20ab67ef-ef8b-4f24-8783-1ff18cfe7168

Done. Added non-static (instance) property fetch test cases as requested by staabm:

bug-2861.php: Added InstancePropertyAccess class with $this->default and $obj->default reads guarded by property_exists()

bug-2861-assign.php: Added testInstance() and testInstanceObj() methods with $this->default = 'value' and $obj->default = 'value' writes guarded by property_exists()

AccessPropertiesRuleTest: Added testBug2861() to verify instance property reads don't trigger errors

AccessPropertiesInAssignRuleTest: Added testBug2861() to verify instance property writes don't trigger errors

All 12131 tests pass and make phpstan reports no errors.

-Original file line number
+Diff line change
@@ Expand Up / @@ -1644,7 +1644,7 @@ parameters: @@
     		-
     			rawMessage: 'Doing instanceof PHPStan\Type\Constant\ConstantStringType is error-prone and deprecated. Use Type::getConstantStrings() instead.'
     			identifier: phpstanApi.instanceofType
-    			count: 2
+    			count: 1
     			path: src/Type/Php/PropertyExistsTypeSpecifyingExtension.php
     		-
@@ Expand Down @@

-Original file line number
+Diff line change
@@ Expand Up / @@ -3,8 +3,14 @@ @@
     namespace PHPStan\Rules\Properties;
     use PhpParser\Node;
+    use PhpParser\Node\Arg;
+    use PhpParser\Node\Expr\ClassConstFetch;
+    use PhpParser\Node\Expr\FuncCall;
     use PhpParser\Node\Expr\StaticPropertyFetch;
+    use PhpParser\Node\Identifier;
     use PhpParser\Node\Name;
+    use PhpParser\Node\Name\FullyQualified;
+    use PhpParser\Node\Scalar\String_;
     use PHPStan\Analyser\NullsafeOperatorHelper;
     use PHPStan\Analyser\Scope;
     use PHPStan\DependencyInjection\AutowiredParameter;
@@ Expand Down Expand Up / @@ -256,6 +262,19 @@ @@
     				]);
     			}
+    			if ($node->class instanceof Name) {
+    				$classExpr = new ClassConstFetch($node->class, new Identifier('class'));
+    			} else {
+    				$classExpr = $node->class;
+    			}
+    			$propertyExistsCall = new FuncCall(new FullyQualified('property_exists'), [
+    				new Arg($classExpr),
+    				new Arg(new String_($name)),
+    			]);
+    			if ($scope->getType($propertyExistsCall)->isTrue()->yes()) {
+    				return [];
+    			}
     			return array_merge($messages, [
     				RuleErrorBuilder::message(sprintf(
     					'Access to an undefined static property %s::$%s.',
@@ Expand Down @@

-Original file line number
+Diff line change
@@ Expand Up / @@ -15,11 +15,13 @@ @@
     use PHPStan\Reflection\FunctionReflection;
     use PHPStan\Rules\Properties\PropertyReflectionFinder;
     use PHPStan\Type\Accessory\HasPropertyType;
+    use PHPStan\Type\ClassStringType;
     use PHPStan\Type\Constant\ConstantBooleanType;
     use PHPStan\Type\Constant\ConstantStringType;
     use PHPStan\Type\FunctionTypeSpecifyingExtension;
     use PHPStan\Type\IntersectionType;
     use PHPStan\Type\ObjectWithoutClassType;
+    use PHPStan\Type\UnionType;
     use function count;
     #[AutowiredService]
@@ Expand Down Expand Up / @@ -66,17 +68,35 @@ public function specifyTypes( @@
     		}
     		$objectType = $scope->getType($args[0]->value);
-    		if ($objectType instanceof ConstantStringType) {
-    			return new SpecifiedTypes([], []);
-    		} elseif ($objectType->isObject()->yes()) {
-    			$propertyNode = new PropertyFetch(
+    		if ($objectType->isString()->yes()) {
+    			return $this->typeSpecifier->create(
+    				new FuncCall(new FullyQualified('property_exists'), $node->getRawArgs()),
+    				new ConstantBooleanType(true),
+    				$context,
+    				$scope,
+    			);
+    		}
+    		if (!$objectType->isObject()->yes()) {
+    			return $this->typeSpecifier->create(
     				$args[0]->value,
-    				new Identifier($propertyNameType->getValue()),
+    				new UnionType([
+    					new IntersectionType([
+    						new ObjectWithoutClassType(),
+    						new HasPropertyType($propertyNameType->getValue()),
+    					]),
+    					new ClassStringType(),
+    				]),
+    				$context,
+    				$scope,
     			);
-    		} else {
-    			return new SpecifiedTypes([], []);
     		}
+    		$propertyNode = new PropertyFetch(
+    			$args[0]->value,
+    			new Identifier($propertyNameType->getValue()),
+    		);
     		$propertyReflection = $this->propertyReflectionFinder->findPropertyReflectionFromNode($propertyNode, $scope);
     		if ($propertyReflection !== null) {
     			if (!$propertyReflection->isNative()) {
@@ Expand Down @@

-Original file line number
+Diff line change
@@ -0,0 +1,23 @@
+    <?php declare(strict_types = 1);
+    namespace Bug2861Nsrt;
+    use function PHPStan\Testing\assertType;
+    /**
+     * @param object|string $objectOrClass
+     */
+    function testObjectOrString($objectOrClass): void {
+    	if (property_exists($objectOrClass, 'foo')) {
+    		assertType('class-string|(object&hasProperty(foo))', $objectOrClass);
+    	}
+    }
+    /**
+     * @param object|class-string $objectOrClass
+     */
+    function testObjectOrClassString($objectOrClass): void {
+    	if (property_exists($objectOrClass, 'bar')) {
+    		assertType('class-string|(object&hasProperty(bar))', $objectOrClass);
+    	}
+    }

-Original file line number
+Diff line change
@@ Expand Up / @@ -253,4 +253,9 @@ public function testCloneWith(): void @@
     		]);
     	}
+    	public function testBug2861(): void
+    	{
+    		$this->analyse([__DIR__ . '/data/bug-2861-assign.php'], []);
+    	}
     }

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Suppress undefined static property error when `property_exists()` guard is present #5544

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GitHub Actions / Mutation Testing (8.4, ubuntu-latest)

GitHub Actions / Mutation Testing (8.3, ubuntu-latest)

staabm May 20, 2026

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-Original file line number
+Diff line change
@@ Expand Up / @@ -1294,4 +1294,12 @@ public function testBug13539(): void @@
     		]);
     	}
+    	public function testBug2861(): void
+    	{
+    		$this->checkThisOnly = false;
+    		$this->checkUnionTypes = true;
+    		$this->checkDynamicProperties = true;
+    		$this->analyse([__DIR__ . '/data/bug-2861.php'], []);
+    	}
     }

-Original file line number
+Diff line change
@@ -0,0 +1,33 @@
+    <?php declare(strict_types = 1);
+    namespace Bug2861Assign;
+    class Foo {
+    	public static function test(): void {
+    		if (property_exists(static::class, 'default')) {
+    			static::$default = 'value';
+    		}
+    	}
+    	/**
+    	 * @param class-string $className
+    	 */
+    	public static function testExpr(string $className): void {
+    		if (property_exists($className, 'default')) {
+    			$className::$default = 'value';
+    		}
+    	}
+    	public function testInstance(): void {
+    		if (property_exists($this, 'default')) {
+    			$this->default = 'value';
+    		}
+    	}
+    	/** @param self $obj */
+    	public function testInstanceObj(self $obj): void {
+    		if (property_exists($obj, 'default')) {
+    			$obj->default = 'value';
+    		}
+    	}
+    }

-Original file line number
+Diff line change
@@ -0,0 +1,71 @@
+    <?php declare(strict_types = 1);
+    namespace Bug2861;
+    trait EnumTrait {
+    	/** @var mixed */
+    	protected $value;
+    	/** @param mixed $value */
+    	final public function __construct($value) {
+    		$this->value = $value;
+    	}
+    	/** @return static|null */
+    	public static function getDefault() {
+    		if (property_exists(static::class, 'default') && null !== static::$default) {
+    			$obj = static::$default;
+    			return new static($obj);
+    		}
+    		return null;
+    	}
+    }
+    class Foo {
+    	use EnumTrait;
+    	public const BLA = 'bla';
+    }
+    class Bar {
+    	use EnumTrait;
+    	public static $default = 'bla';
+    	public const BLA = 'bla';
+    }
+    class Baz {
+    	use EnumTrait;
+    	/** @return static|null */
+    	public static function getDefault2() {
+    		if (property_exists(self::class, 'default') && null !== self::$default) {
+    			return new static(self::$default);
+    		}
+    		return null;
+    	}
+    }
+    class ExpressionBased {
+    	/**
+    	 * @param class-string $className
+    	 */
+    	public static function test(string $className): void {
+    		if (property_exists($className, 'default')) {
+    			echo $className::$default;
+    		}
+    	}
+    }
+    class InstancePropertyAccess {
+    	public function test(): void {
+    		if (property_exists($this, 'default')) {
+    			echo $this->default;
+    		}
+    	}
+    	/** @param self $obj */
+    	public function testObj(self $obj): void {
+    		if (property_exists($obj, 'default')) {
+    			echo $obj->default;
+    		}
+    	}
+    }

Suppress undefined static property error when property_exists() guard is present #5544

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Suppress undefined static property error when property_exists() guard is present #5544

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Suppress undefined static property error when `property_exists()` guard is present #5544

Suppress undefined static property error when `property_exists()` guard is present #5544