PHP Never Return Type: Use Cases

never is a return type for code paths that always throw or terminate the process.

What It Does

never is a return type for code paths that always throw or terminate the process. The following examples distinguish a normal use case, a boundary case and a practical application.

Requirements and Compatibility

PHP 8.x and a local test environment. Apply input validation, correct error handling and the requirements of any optional libraries.

The code focuses on the core concept. Production implementation may also need routes, validation, persistence, authorization or deployment tooling.

Example 1: Basic Behavior

Start with the smallest meaningful working case.

<?php
function stopProcessing(string $reason): never { throw new RuntimeException($reason); }
try { stopProcessing('Invalid workflow'); } catch (RuntimeException $e) { echo $e->getMessage(); }

Example 2: Another Case

Examine the edge case and the observable result.

<?php
function rejectRequest(int $status): never { http_response_code($status); exit; }
if (false) rejectRequest(403);
echo 'Execution continues only when allowed';

Practical Example: Putting It to Use

A never helper expresses a branch that terminates through an exception.

<?php
function abortWhenInvalid(bool $valid): void { if (!$valid) { failRequest('invalid'); } }
function failRequest(string $reason): never { throw new DomainException($reason); }
try { abortWhenInvalid(false); } catch (DomainException $e) { echo 'Rejected'; }

Important Behavior and Edge Cases

It is incompatible with returning normally, even without a value.

Comparison with Related Functions or Approaches

Common Beginner Mistakes

Key Takeaways

• never is a return type for code paths that always throw or terminate the process.
• It is incompatible with returning normally, even without a value.
• Use a nullable return type when a lookup may return without a result.

Before adapting these examples, verify the return values, test the failure paths and confirm that your application meets its security and environment requirements.