Re: RFC: Marking return values as important (#[\NoDiscard])

On Wed, Jan 29, 2025 at 4:14 PM Tim Düsterhus <tim@bastelstu.be> wrote: > Hi > > Volker and I would like to start discussion on our RFC to allow "Marking > return values as important (#[\NoDiscard])". > > Please find the following resources for your reference: > > - RFC: https://wiki.php.net/rfc/marking_return_value_as_important�E��� > Ї<́�HK� > - Implementation: https://github.com/php/php-src/pull/17599 > > Best regards > Tim Düsterhus > I don't see this as something useful when you want to force interactions with variables. I do see value in using this for the keeping and closing of resources, but the only error you should ever get is when you use #[NoDiscard] without a return value. https://3v4l.org/L4bOc <?php #[NoDiscard] function lockFile(string $path) { $handle = fopen($path, 'r+'); if (! $handle || ! flock($handle, LOCK_EX)) { throw new RuntimeException('Failed locking ' . $path); } return $handle; } // what we write function main() { lockFile($path); doSomething(); echo 'hi'; } // gets rewritten internally to something like function main() { $hidden = lockFile($path); doSomething(); echo 'hi'; unset($hidden); } // if we do assign it, we omit it all // what we write here would not get rewritten function main() { $handle = lockFile($path); doSomething(); echo 'hi'; } // if we were to ever get a "using"-like // what we write function main() { using { lockFile($path); doSomething(); } echo 'hi'; } // gets rewritten internally to something like function main() { $hidden = lockFile($path); doSomething(); unset($hidden); echo 'hi'; }