Error Identifier: empty.property

← Back to empty.*

Every error reported by PHPStan has an error identifier. Here’s a list of all error identifiers. In PHPStan Pro you can see the error identifier next to each error and filter errors by their identifiers.

Code example #

<?php declare(strict_types = 1);

class Bar {}

class Foo
{
	public Bar $bar;

	public function __construct()
	{
		$this->bar = new Bar();
	}
}

function test(): void
{
	$foo = new Foo();
	$foo->bar = new Bar();
	if (empty($foo->bar)) {
		echo 'empty';
	}
}

Why is it reported? #

The property used inside empty() has a type that PHPStan can fully evaluate for emptiness. When the property type is always falsy or never falsy, the empty() check is either always true or always false, indicating a logic error or a check that should be written more explicitly.

In the example above, $foo->bar is typed as Bar, which is an object and can never be falsy. The empty() call on it always returns false.

How to fix it #

Remove the redundant empty() check since an object value is never falsy:

 function test(): void
 {
 	$foo = new Foo();
 	$foo->bar = new Bar();
-	if (empty($foo->bar)) {
-		echo 'empty';
-	}
+	echo $foo->bar::class;
 }

If the property can legitimately be nullable, adjust the type to reflect that:

 class Foo
 {
-	public Bar $bar;
+	public ?Bar $bar;

 	public function __construct()
 	{
-		$this->bar = new Bar();
+		$this->bar = null;
 	}
 }

How to ignore this error #

You can use the identifier empty.property to ignore this error using a comment:

// @phpstan-ignore empty.property
codeThatProducesTheError();

You can also use only the identifier key to ignore all errors of the same type in your configuration file in the ignoreErrors parameter:

parameters:
	ignoreErrors:
		-
			identifier: empty.property

Rules that report this error #

• PHPStan\Rules\Variables\EmptyRule [1]
• PHPStan\Rules\Variables\IssetRule [1]
• PHPStan\Rules\Variables\NullCoalesceRule [1]