On Fri, July 11, 2025 at 05:00 G. P. Banyard wrote:
>> On Monday, 30 June 2025 at 10:26, Nicolas Grekas wrote:
>> ...
>> The latter, cast-from-bool, I think they're all useful improvements. While
>> most likely harmless in all the specific
>> cases of the PR, doing e.g. an strpos() on false feels hardly legit. I'm
>> therefore sympathetic to making these changes.
>>
>> For cast-to-bool, I'm WAY less convinced. From the PR above, explicit casts
>> like "return (bool) preg_match(...)"
>> on a method that returns a "bool" or "(bool) ($this->loggedErrors & $type)"
>> are a clear downgrade: it makes the
>> typing PHP just more verbose without any real benefit. That doesn't look
>> worth asking the whole ecosystem to fix
>> those deprecations. It is especially hard to see this as an improvement when
>> comparing to using the same
>> expressions with e.g. the "if ()" operator, which doesn't need the explicit
>> cast (and shouldn't of course).
>From my experience there is a very real benefit to deprecating both
>cast-from-bool and cast-to-bool.
Let me give an example of both.
Recently had to fix some legacy code where the result of `filemtime` was being
passed to `gmdate` to format
the modification timestamp. `filemtime` returns false on failure, but this is
silently coerced to zero
(a valid timestamp) when passed to the int parameter, which would result in the
script continuing with bad
data instead of halting with a type error.
Cast-to-bool can cause the same kinds of issues, which are sometimes even
harder to notice. Consider the following:
function processArray(array $items, bool $hasCertainKey) { ... }
$keyOrFalse = array_search('my value', $items);
processArray($items, $keyOrFalse);
It's very easy to miss the bug in this code, especially since it seems to
function correctly as long as 'my value'
is not in the array, or is not the first item in the array. However, when it's
at index 0 the key will be silently
coerced to false and the array will be incorrectly processed as though the
value is not in the array.
I believe deprecating type juggling to/from bool will help avoid creating bugs
like this (and likely
surface existing ones that should be fixed).
Kind regards,
Theodore
