Re: RE: [PHP-DEV] Re: [PHP-QA] $obj = new foo() patch

Hi Mike & others! Mike Heath wrote: > > A simple fix would be: > <?php > class B { > function bb() { > global $a; > echo "b"; > $a->aa(); > } > } > class A { > function aa() { > echo "A"; > } > } > > function t() { > > global $a; > $GLOBALS['a'] = new A; > $a->aa(); > > global $b; > $GLOBALS['b'] = new B; > $b->bb(); > } > > t(); > ?> > > If new is returning a reference of course this example doesn't work. The > problem lies in the fact the global $a references the same data the real $a > uses. The previously posted example tells the local instance of $a and $b > to point to some other data and does not affect the real $a or $b. Hmm. I thought that $GLOBALS['a'] = new A; is absolute equivalent to global $a; $a = new A; I don't care in this example what is returned by operator 'new'. I suppose, that $a in second case should be absolutely equivalent to GLOBALS['a'] regardsless right part of '=' sign. > > There appears to be a trade-off here. Either allow people to use global as > in the example posted by Maximov or apply the patch as is. Allowing new to > return a reference is definitely needed. It is a bug that comprimises > enterprise level OO design and forces sloppy OO code in PHP. Don't forget about thousands lines of code which use old behaveour. Anyway, I don't understand why Andi's patch can work in both cases. OK, 'new' returns reference. But $a should be === $GLOBALS['a'], IMO. Or I've missed something? > > One option might also be to use $obj = &new foo() Zeev pointed out that > this wouldn't work for passing doing something like bar(&new foo()) which is > a limitation I think we can live with. Dan Rodriguez <danjrod@terra.es> > also has created a patch to do that. > > If the above option won't work than it appears we have to choose between > forcing poor OO design and modifying coding practices. In my opinion, good > design is far more important than changing coding practices. If we want to force 'rich' OO design, let's wait until PHP 5.0. IMO, a few peoply will upgrade to 4.0.4 if they'll have to rewrite their code (possibly, a LOT of code). But, I think, core team understands importance of compatibility issue. That's why Andi reversed the patch for now, isn't it? ;-) Best regards, KIR P.S. BTW, my example is from PHPLIB library. > > Don't worry Andi. This bug hasn't started to annoy me... it's been annoying > me for 2 months and I'm hoping this can be rectified in 4.0.4. :) > > Thanks, > > Mike > > -----Original Message----- > From: Kirill Maximov [mailto:kir@actimind.com] > Sent: Friday, November 10, 2000 3:44 AM > To: Andi Gutmans > Cc: PHP Development; php-qa@lists.php.net > Subject: [PHP-DEV] Re: [PHP-QA] $obj = new foo() patch > > Andi Gutmans wrote: > > > > Guys, > > > > I have submitted a patch to the Zend Engine which is considered > > experimental. It is supposed to fix the problem with the $obj = new foo() > > statement when the constructor of foo() assigns $this by reference to > other > > symbol table entries. Basically, the Zend Engine will explicitly assign > new > > foo() by reference to $obj because this is pretty much the only thing > which > > makes sense in this case. > > NOTE: If you do $obj2 = $obj1 = new foo(), "$obj2 = $obj1" will still > > assign by value and not by reference. > > This patch is only meant to fix this problematic bug which has about 5 > > entries in the bugs database. > > Please check it out. If there are any problems/concerns with this bug it > is > > best to leave it out for 4.0.4 but it should not harm anyone's scripts. > > The following bugs are probably solved now: 6529, 6896, 7454, 7455, 7482 > > Anyway, please grab a fresh CVS tree and check that your OOP code still > > works :) > > Thanks! > > Andi > > This code doesn't work no more as it did before: > > <?php > class B { > function bb() { > global $a; > echo "b"; > $a->aa(); > } > } > class A { > function aa() { > echo "A"; > } > } > > function t() { > > global $a; > $a = new A; > $a->aa(); > > global $b; > $b = new B; > $b->bb(); > } > > t(); > ?> > > Output should be AbA. > I get: > > Ab > Fatal error: Call to a member function on a non-object in > /h/home/kir/public_html/a.php on line 18 > > -- > > With best regards, > Kirill Maximov > QA team. > > -- > PHP Quality Assurance Mailing List <http://www.php.net/> > To unsubscribe, e-mail: php-qa-unsubscribe@lists.php.net > For additional commands, e-mail: php-qa-help@lists.php.net > To contact the list administrators, e-mail: php-list-admin@lists.php.net -- With best regards, Kirill Maximov

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