> On 16 Sep 2017, at 01:27, Arvids Godjuks <arvids.godj...@gmail.com> wrote: > > 2017-09-15 20:52 GMT+03:00 Ryan Pallas <derokor...@gmail.com>: > >>> On Fri, Sep 15, 2017 at 11:38 AM, <ilija.tov...@me.com> wrote: >>> >>> Hi Ryan >>> >>> I can see your argument. The reasoning behind it is that a function in >> the >>> standard library should not encourage unsafe code. Admittedly, since this >>> function is rarely used except for templating systems one could call >> this a >>> non-issue. I just wanted to bring it up. >>> >> >> That makes sense. What about performance difference? On a reasonable sized >> array (not 10k items and not 2) which is faster? >> >> extract($array); >> >> - or - >> >> foreach ($array as $key => $value) >> $$key = $value; >> >> Honestly, I don't know (ps 2 lines without braces instead of 3!) >> >> >>> >>> Regards >>> >>> >>> On 15 Sep 2017, 19:30 +0200, Ryan Pallas <derokor...@gmail.com>, wrote: >>> >>> >>> >>> On Sep 15, 2017 11:22 AM, <ilija.tov...@me.com> wrote: >>> >>> Hi! >>> >>> The `extract` function takes an associative array and puts it into the >>> local symbol table. >>> http://php.net/manual/en/function.extract.php >>> >>> ``` >>> $array = [ >>> ‘foo’ => ‘foo’, >>> ‘bar’ => ‘bar’, >>> ]; >>> >>> extract($array); >>> >>> print $foo; // "foo" >>> ``` >>> >>> As a second parameter the `extract` function takes some options to make >>> this function less dangerous, like `EXTR_SKIP` that prevents an existing >>> local variable of being overwritten. There’s a few more options, go ahead >>> and take a look at the documentation. `EXTR_OVERWRITE` is the default one >>> though. You can also pass a prefix for the variable names as a third >>> argument. >>> >>> I seriously doubt the usefulness of this function, especially looking at >>> the potential risks. The fact that overwriting the local variables is the >>> default behaviour doesn’t make it any better. I suggest deprecating it in >>> PHP 7.3 and removing it in 8. >>> >>> In a whole Symfony-Stack (3.4) with all of it’s dependencies I could only >>> find two usages of this function, both of which could be easily rewritten >>> in vanilla PHP: >>> https://github.com/symfony/symfony/blob/master/src/Symfony/ >>> Component/Templating/PhpEngine.php#L148 >>> https://github.com/symfony/symfony/blob/master/src/Symfony/ >>> Component/Templating/PhpEngine.php#L158 >>> >>> Only downside: A polyfill is probably impossible since you cannot mutate >>> the local symbol table of the callee (as far as I’m aware). >>> >>> Any thoughts? >>> >>> >>> I see no gain by removing this function. I've also seen it used for >>> templating quite often. Yes the functionality could be changed not to use >>> extract and end up working the same to the consumer but why make people >>> rewrite these things for no apparent gain (and likely a small performance >>> hit)? >>> >>> >>> Regards >>> >>> >>> >>> >> > > Hi Ryan, > well, basically, none. Results are from a Q6600 machine and under windows, > so your mileage probably gonna be quite better :) > > C:\Users\psihius\Documents\web>php -v > PHP 7.1.5 (cli) (built: May 9 2017 19:48:36) ( NTS MSVC14 (Visual C++ > 2015) x64 ) > Copyright (c) 1997-2017 The PHP Group > Zend Engine v3.1.0, Copyright (c) 1998-2017 Zend Technologies > C:\Users\psihius\Documents\web>php -d memory_limit=-1 test.php > 6.884626150131226 - Creating arrays > 2.035606861114502 - foreach > 2.128609180450439 - extract > > The code: > > define('ITERATIONS', 10000000); > > $__time = microtime(true); > > $__array = $__array2 = []; > for ($__i = 0; $__i < ITERATIONS; ++$__i) { > $__array['a'.$__i] = $__i; > $__array2['b'.$__i] = $__i; > } > echo number_format(microtime(true) - $__time, 15, '.', ''), PHP_EOL; > > $__time = microtime(true); > foreach ($__array as $__key => $__variable) { > $$__key = $__variable; > } > echo number_format(microtime(true) - $__time, 15, '.', ''), PHP_EOL; > > $__time = microtime(true); > foreach ($__array2 as $__key => $__variable) { > $$__key = $__variable; > } > echo number_format(microtime(true) - $__time, 15, '.', ''), PHP_EOL; > > -- > Arvīds Godjuks > > +371 26 851 664 > arvids.godj...@gmail.com > Skype: psihius > Telegram: @psihius https://t.me/psihius
Hi all, If you want to reduce unintended consequences while retaining functionality, the default flag could be changed to EXTR_SKIP. Yes it affects BC but it's also much simpler to fix than if the functionality is gone completely, and in the case of templating it's probably already used that way in most cases anyway. Cheers Stephen -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: http://www.php.net/unsub.php
