[RFC] Throw Exception on Attempt of Constant Redefinition

In general, you are right, but this is possible only if application ignores Error exceptions... ________________________________ From: morrison.levi@gmail.com <morrison.levi@gmail.com> on behalf of Levi Morrison <levim@php.net> Sent: Friday, June 10, 2016 11:50:26 PM To: Dmitry Stogov Cc: PHP internals Subject: Re: [PHP-DEV] [RFC] Throw Exception on Attempt of Constant Redefinition On Fri, Jun 10, 2016 at 2:06 PM, Dmitry Stogov <dmitry@zend.com> wrote:

Dmitry, I am not sure this change will actually allow constant propagation either. Consider this code: <?php const Foo = 1; class FooFactory { static function make() { return Foo; } } ?> In this series of events: - Foo is declared to be 0 - This above file is now included inside a try-catch block that catches the error - FooFactory::make() is now called If Foo = 1 was propagated then FooFactory::make() will return 1 instead of 0. Am I missing something?

On 11.06.2016 at 17:01, Fleshgrinder wrote:

I'm also somewhat concerned with regard to turning a notice into an exception in a minor version. I would prefer to have an alternative voting option to deprecate constant redefinition in 7.1 and to finally disallow it in 8.0. It might be helpful to make a rough plan when PHP 8.0 will be released. If that will be far in the future (say 5 years or even more), such a change might be okay for a minor version (presumably nobody wants to wait such a long time for this and similar improvements), but if PHP 8.0 will be released much earlier, it might be tolerable to wait and to not break semantic versioning.

On 16/06/16 07:44, Dmitry Stogov wrote:

Doesn't anybody remember the problems which STILL have to be resolved with changes in PHP5.2/3/4 which require the assistance of programmers to fix naive users problems. Now many of the new features being added will not be currently used in legacy code, but can anybody ensure that all of the BC changes being currently pushed for will not cause a more general PHP5.4 style block to upgrading? HAVING to add changes to code to retain a legacy style of operation is something that should only happen in a major version. Isn't this why most big projects no longer bother with many small version changes? What is Firefox up to now ... However going down that root does require LTS builds which is something else which is maintaining PHP5.3 in the field. I am now getting used to the changes in PHP7, but the current roadmap for PHP7.1 is just another PHP5.4 in my book and it does create a case for my simply rolling back to PHP5 since none of my production systems have been fully updated so they can use PHP7 yet ...

Got it :( Then this may be a serious BC break, and it's better to depricate it in 7.1 and throw exception only in 8. Thanks. Dmitry. On Thu, Jun 16, 2016 at 8:14 PM +0300, "Stanislav Malyshev" <smalyshev@gmail.com<mailto:smalyshev@gmail.com>> wrote: Hi!

I would propose to not throw an error if constant is redefined to exactly the same value. Some of the code might be doing this unknowingly, e.g. by writing include instead of include_once, and there's no real reason to break it.