count() emitting an E_WARNING

Question

Prior to PHP 7.2 using count() on a scalar value or non-countable object would return 1 or 0.

For example: https://3v4l.org/tGRDE

Answer 1

The problem is that calling count() on a scalar or object that doesn't implement the Countable interface returns 1, which can easily hide bugs.

Given the following:

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() nor handle_value().
Also, no indication would be given that neither were called.

By default, this will still return 1, though will additionally log a warning. If anything, this warning will bring attention to potential bugs in the code.

See Counting Non-Countables for further information.