On Fri, Apr 29, 2016 at 9:10 PM, Stanislav Malyshev <smalys...@gmail.com> wrote:
> Hi! > > > I'd like to submit a small RFC for your consideration, which ensures > > something that really ought to be a given already: If you use $this in an > > instance method, you should actually get a $this (and not NULL). > > > > https://wiki.php.net/rfc/forbid_null_this_in_methods > > > > As this is targeting PHP 7.1, the RFC is careful to retain compatibility > > with certain legacy PHP 4 code patterns. > > Unfortunately, this does not exactly preserve compatibility. Consider: > > public function legacyMethod() { > if(is_null($this)) { > trigger_error(E_DEPRECATED, "legacyMethod() should be called with an > object now!"); > return self::getDefaultInstance()->legacyMethod(); > } > print "I am an ugly legacy method!"; > $this->doSomeStuff(); > return true; > } > > Unfortunately, I've seen this pattern not once when dealing with APIs > which were grown from PHP 4 code and must maintain BC - e.g. have code > relying on legacyMethod() both being called statically and called on an > object and legacyMethod() being overridden by extending classes. It is > an ugly code and an ugly situation to be in, but it is a real pattern > that happens. > > Despite the RFC claiming HHVM does not support this pattern, it does: > https://3v4l.org/1QrY7 > Unlike PHP, it doesn't even throw deprecated error in that case. > Wow, thanks for pointing this out! I'm really stumped as to why I thought HHVM doesn't support it. I've dropped the remark now. > Given that this RFC does not seem to enable anyone to do anything > additional that couldn't be done before, just removes the features from > language, I see any advantage in doing it so far. > > I also do not think enabling using $this as a regular variable is a > particularly good idea. It does not add anything - there's no real need > to name your variables specifically "$this", you can choose any other > name - but it creates potential both for confusion and for weird errors > when you refactor stuff. Again, don't see any real advantage in this. > The thing is that currently we allow using $this as a normal variable in some ways (accepted as a function argument for example), but then don't allow it in others (accessing properties on it). However, I agree that this is probably the wrong direction to go here, instead we should make sure that $this cannot be used at all. I will consider this. Thanks, Nikita
