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Error Identifier: ternary.alwaysFalse

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);

function doFoo(): void
{
    $zero = 0;
    $result = $zero ? 'yes' : 'no';
}

Why is it reported? #

The condition of the ternary operator always evaluates to false, which means the “true” branch can never be reached. This typically indicates a logic error, dead code, or a condition that does not express the intended check.

In the example above, $zero is assigned 0, which is always falsy in PHP, so the ternary will always evaluate to 'no'.

How to fix it #

Fix the condition so it can actually evaluate to both true and false:

 <?php declare(strict_types = 1);
 
-function doFoo(): void
+function doFoo(int $value): void
 {
-    $zero = 0;
-    $result = $zero ? 'yes' : 'no';
+    $result = $value > 0 ? 'yes' : 'no';
 }

Or if the condition is intentionally always false, simplify the code by using the false-branch value directly:

 <?php declare(strict_types = 1);
 
 function doFoo(): void
 {
-    $zero = 0;
-    $result = $zero ? 'yes' : 'no';
+    $result = 'no';
 }

How to ignore this error #

You can use the identifier ternary.alwaysFalse to ignore this error using a comment:

// @phpstan-ignore ternary.alwaysFalse
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: ternary.alwaysFalse

Rules that report this error #

• PHPStan\Rules\Comparison\TernaryOperatorConstantConditionRule [1]

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