Re: [RFC] [DISCUSSION] Make constructors and destructors return void

Hey Bob, Your examples (regarding constructors/destructors) do make sense since you are using these methods for what they should be used: initialization and freeing resources. But, this is off-topic to the RFC. This RFC only proposes to enforce no-return rule on constructors/destructors. And based on my previous reply, top 2,000 Composer packages that have a BC break don't actually return anything (early returns and returns that don't change code behavior don't count). Your examples regarding __toString, __invoke and __serialize are also not relevant to this RFC. Although, I do understand that you were responding to email and I'm thankful for that :) Best regards, Benas On Thu, Jun 18, 2020, 7:43 PM Bob Weinand <bobwei9@hotmail.com> wrote: > Hey, > > Am 18.06.2020 um 17:18 schrieb Benas IML <benas.molis.iml@gmail.com>: > > Hey Bob, > > Magic methods are **never** supposed to be called directly (even more if > that method is a constructor or a destructor). If that's not the case, it's > just plain bad code. But by enforcing these rules, we make sure that less > of that (bad code) is written and as a result, we make PHP code less > bug-prone and easier to debug. That's also most likely the reason why > > > __construct() is invoked directly on parent calls, sometimes to > reinitialize an object or > after ReflectionClass::newInstanceWithoutConstructor. > > I invoke __destruct() directly when needing an early freeing of existing > resources. > > "ensure magic methods' signature" RFC opted in to validate > __clone > method's signature and ensure that it has void return > type. > > Just for the sake of making sure that you understand what I mean, here are > a couple of examples that show that no magic method is ever supposed to be > called directly: > ```php > // __toString > (string) $object; > > > I like using ->__toString() in favor of (string) casts when the variable > is guaranteed to be an object to highlight that and avoid magic-ness. > > // __invoke > $object(); > > > Same here, unless the object is a closure. > > // __serialize > serialize($object); > ``` > > > Can't argue much about that one, I never use serialize(). > > Moreover, by validating constructors/destructors and allowing an explicit > void return type declaration, we are becoming much more > consistent > (something that PHP is striving for) with other magic methods (e. g. > __clone). > > > Yeah, __clone() is odd. No idea why. > > Also, saying that "sometimes you have valid information to pass from the > parent class" is quite an overstatement. After analyzing most of the 95 > Composer packages that had a potential BC break, I found out that either > they wanted to return early (that is still possible to do using qɆ§-= > ¡°&°—i „ return;) > or they added a return something; for no reason. Thus, no > libraries > actually returned something useful and valid from a constructor (as they > shouldn't). > > Last but certainly not least, constructors have one and only one > responsibility - to initialize an object. Whether you read Wikipedia's or > PHP manual's definition, a constructor does just that. It initializes. So, > the PHP manual is perfectly correct and documents the correct return type > that a constructor should have. > > > It also is generally a bad idea to have side effects in constructors, but > _sometimes_ it is justified. Only because something mostly is a bad idea, > it is not always. > Also note that other languages completely forbid manual ctor calls. But > PHP doesn't (and for good reason, like after > using ReflectionClass::newInstanceWithoutConstructor). > > Bob > > Best regards, > Benas > > On Thu, Jun 18, 2020, 4:06 PM Bob Weinand <bobwei9@hotmail.com> wrote: > >> > Am 17.06.2020 um 01:10 schrieb Benas IML <benas.molis.iml@gmail.com>: >> > >> > Hey internals, >> > >> > This is a completely refined, follow-up RFC to my original RFC. Based >> on the >> > feedback I have received, this PR implements full validation and >> implicitly >> > enforces void rules on constructors/destructors while >> > also allowing to >> > declare an **optional** explicit void return type. >> > Note, that there >> is a >> > small but justifiable BC break (as stated by the RFC). >> > >> > RFC: https://wiki.php.net/rfc/make_ctor_ret_void >> > >> > Best regards, >> > Benas Seliuginas >> >> Hey Benas, >> >> I do not see any particular benefit from that RFC. >> >> Regarding what the manual states - the manual is wrong there and thus >> should be fixed in the manual. This is not an argument for changing engine >> behaviour. >> >> Sometimes a constructor (esp. of a parent class) or destructor may be >> called manually. Sometimes you have valid information to pass from the >> parent class. >> With your RFC an arbitrary restriction is introduced necessitating an >> extra method instead. >> >> In general that RFC feels like "uh, __construct and __destruct are mostly >> void, so let's enforce it … because we can"? >> >> On these grounds and it being an additional (albeit mostly small) >> unnecessary BC break, I'm not in favor of that RFC. >> >> Bob > > >