Re: [PHP-DEV] Access property of object stored in a constant
On Sat, Aug 19, 2023, at 4:21 AM, Claude Pache wrote: > At the time I filed https://github.com/php/php-src/issues/10497, I was > merely exploring the potential of the new ability to have an object in > a constant. The potential use I had back in my head was the following. > Currently, I store some settings in global constants. I was > contemplating replacing those by properties of a readonly object stored > in a global constant. (A fatal issue I discovered later in my journey > is that readonly properties can only be initialised by code inside the > class itself.) As a tangent here, that has a workaround: https://peakd.com/hive-168588/@crell/php-tricks-access-control-bypass Which I make use of in Crell/Serde, which is then used by my own config library to produce exactly what you describe: https://github.com/Crell/Config --Larry Garfield -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: https://www.php.net/unsub.php
Re: [PHP-DEV] Access property of object stored in a constant
Hi Juliette > > Since https://wiki.php.net/rfc/new_in_initializers we can store > > objects in global constants. However, we may not actually read or > > write to the properties of those objects without first fetching the > > constant into a local variable. > > > > const a = new stdClass; > > a->b = 42; // Fatal error: Cannot use temporary expression in write context > > $a = a; > > $a->b = 42; // Works fine > > > > This issue was reported twice, so it seems like this code is generally > > expected to work. > > https://github.com/php/php-src/issues/10497 > > https://github.com/php/php-src/issues/11781 > > > > I have created a patch here to add support for this syntax: > > https://github.com/php/php-src/pull/11788 > > I totally understand that people are trying to do this, but this still > very much feels like scope creep. > > IIRC the new in initializers feature was _intended_ only for enums > (which can't take properties). Now suddenly a "constant" would no longer > be constant... In which case, what's the point of declaring it as a > constant ? This patch doesn't change the mutability of objects in constants, as they already don't offer interior immutability. https://3v4l.org/s7rHE This is analogous to `const` in JavaScript or `readonly` properties in PHP, where we can't change the value of the variable (or const in this case), but we can modify the properties of the object it's pointing to. I believe the main motivation for `new` in constant expressions was to support nested attributes. Enums have their own mechanism for instantiating cases. Since it was decided to expand the support for `new` to global constants, I would expect it to work with other language constructs, unless there's a good reason for it not to. Ilija -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: https://www.php.net/unsub.php
Re: [PHP-DEV] Access property of object stored in a constant
On 18-8-2023 17:27, Ilija Tovilo wrote: Hi everyone Since https://wiki.php.net/rfc/new_in_initializers we can store objects in global constants. However, we may not actually read or write to the properties of those objects without first fetching the constant into a local variable. const a = new stdClass; a->b = 42; // Fatal error: Cannot use temporary expression in write context $a = a; $a->b = 42; // Works fine This issue was reported twice, so it seems like this code is generally expected to work. https://github.com/php/php-src/issues/10497 https://github.com/php/php-src/issues/11781 I have created a patch here to add support for this syntax: https://github.com/php/php-src/pull/11788 Since this is a language change I would like to ask for feedback before merging. As always, if there are concerns I will create a small RFC instead. I will also only merge this for 8.4, as feature freeze for 8.3 has long passed. Ilija I totally understand that people are trying to do this, but this still very much feels like scope creep. IIRC the new in initializers feature was _intended_ only for enums (which can't take properties). Now suddenly a "constant" would no longer be constant... In which case, what's the point of declaring it as a constant ? Smile, Juliette
