On Wed, Jan 29, 2025 at 4:12 PM Tim Düsterhus <t...@bastelstu.be> wrote:
> 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 > - Implementation: https://github.com/php/php-src/pull/17599 Hello everyone, it's been two weeks, but given the feedback we received, we don't feel the discussion didn't reach a conclusive resolution yet. So we wanted to solicit additional opinions. In an attempt to summarize the discussion, how we see it, there are two main points of contention we'd like to discuss further. a) Intentionally discarding the return value The `(void)flock($fp);` syntax was the main thing discussed on the list. With `$_ = flock($fp);` as the most suggested alternative. The issue with using `$_` as it currently stands, is that the unused variable would be cleaned up by OPcache. Should we instead have a special case in OPcache ensuring it does not apply its optimization to a variable if it's named `$_` instead? The semantic difference would be that $_ would keep returned values (and objects) alive and in memory, whereas (void) would discard them immediately. Leading to different times when, for example, destructors would be called. The consequence of this would be that 3rd party tools like IDEs and Static and Dynamic Code Analyzers would also have to build that special case in to not produce "unused variable" warnings. We're also happy to change the secondary vote to "(void) vs $_" as we feel there needs to be a way to discard the return value consistently for this to be a complete and usable feature. b) Naming of the attribute Nobody mentioned this on the list, but before opening a vote we'd like to heard if the attribute name makes sense to you. We've chosen #[NoDiscard] as it's also used in C and C++. See [1] for the full list of references. If you feel this doesn't fit with PHP, we welcome other suggestions. [1] https://wiki.php.net/rfc/marking_return_value_as_important#precedent Kind Regards, Volker -- Volker Dusch Head of Engineering Tideways GmbH Königswinterer Str. 116 53227 Bonn https://tideways.io/imprint Sitz der Gesellschaft: Bonn Geschäftsführer: Benjamin Außenhofer (geb. Eberlei) Registergericht: Amtsgericht Bonn, HRB 22127
