PHP RFC: Counting of non-countable objects

• Version: 0.4
• Date: 2016-10-04
• Author: Craig Duncan php@duncanc.co.uk
• Proposed version: PHP 7.2
• Status: Implemented (in PHP 7.2)
• ML thread: http://externals.io/thread/350

Calling count() on a scalar or object that doesn't implement the Countable interface (http://php.net/manual/en/class.countable.php) returns 1. There are no known use cases for this, and it can easily hide bugs, take the following example:

function handle_records(iterable $iterable)
{
    if (count($iterable) === 0) {
        return handle_empty();
    }
 
    foreach ($iterable as $value) {
        handle_value($value);
    }
}

Passing a Generator that yields nothing would not call handle_empty(), or handle_value(), or alert the developer to the issue.

This RFC proposes adding a warning when calling count() with a parameter that is a scalar, null, or an object that doesn't implement Countable.

Note that the sizeof alias is also affected. http://php.net/manual/en/function.sizeof.php

The call to count() will still return 1 (or 0 for null) so backwards compatibility is maintained.

Environments that display warnings or convert them to more severe errors/exceptions would be affected, but this should just bring attention to a bug in the code.

PHP 7.2

Simple Yes/No vote that doesn't change the language itself so requires 50% + 1 votes to get 'accepted'.

Pull request to handle the change: https://github.com/php/php-src/pull/2185

Initial discussion that led to this RFC's creation: https://github.com/php/php-src/pull/1672

Discussion thread: http://externals.io/thread/350

Voting thread: http://externals.io/thread/409