# Old style constructors in PHP-8

- Thread: https://externals.io/message/103888
- Original archive: https://news-web.php.net/php.internals/103888
- Started by Dmitry Stogov on 2019-01-30T11:11:16+00:00
- Messages: 8
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## #103888 — Dmitry Stogov — 2019-01-30T11:11:16+00:00

URL: https://externals.io/message/103888#103888

Hi,


I've just noticed that Wordpress-4.1 on PHP master started silently produce different output.

The problem that PHP master started to ignore old-style constructors.

They were deprecated in PHP-7 and PHP produced the following warning


Deprecated: Methods with the same name as their class will not be constructors in a future version of PHP; ... has a deprecated constructor


PHP master doesn't produce any warnings and just constructs a class without constructor.

This silent behavior change may become a problem for porting legacy code to PHP-8,

May be, it makes sense to emit fatal error in case of old-style constructor.


Thanks. Dmitry.

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## #103889 — Pierre Joye — 2019-01-30T11:15:33+00:00

URL: https://externals.io/message/103888#103889 · In reply to: #103888

>  to PHP-8,
>
> May be, it makes sense to emit fatal error in case of old-style
> constructor.
>

Absolutely yes. It will be painless then to find them and fix accordingly.
Once officially done, I am sure someone will write code converters as well.


>
> Thanks. Dmitry.

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## #103892 — Sebastian Bergmann — 2019-01-30T11:39:40+00:00

URL: https://externals.io/message/103888#103892 · In reply to: #103889

Am 30.01.2019 um 12:15 schrieb Pierre Joye:
> Once officially done, I am sure someone will write code converters as well.

The no_php4_constructor fixer of php-cs-fixer has been able to 
automatically migrate old-style constructors for years.

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## #103893 — Nikita Popov — 2019-01-30T11:41:45+00:00

URL: https://externals.io/message/103888#103893 · In reply to: #103888

> Hi,
>
>
> I've just noticed that Wordpress-4.1 on PHP master started silently
> produce different output.
>
> The problem that PHP master started to ignore old-style constructors.
>
> They were deprecated in PHP-7 and PHP produced the following warning
>
>
> Deprecated: Methods with the same name as their class will not be
> constructors in a future version of PHP; ... has a deprecated constructor
>
>
> PHP master doesn't produce any warnings and just constructs a class
> without constructor.
>
> This silent behavior change may become a problem for porting legacy code
> to PHP-8,
>
> May be, it makes sense to emit fatal error in case of old-style
> constructor.
>
>
> Thanks. Dmitry.
>

First of all, it is probably important to note that the RFC for this (
https://wiki.php.net/rfc/remove_php4_constructors) explicitly specifies
that in PHP 8 methods with the same name as the class are interpreted as
ordinary methods and no warning or error is thrown. I've CC'd Levi and
Andrea, who authored this RFC.

I think as an end goal, what the RFC specifies is preferable for a number
of reasons:

 * You should be able to call your methods whatever you like. PHP only
reserves the __ prefix for itself.
 * The behavior is consistent with classes inside namespaces, where methods
with the same name as the class are treated as normal methods for a long
time already.
 * The fact that a method has the same name as the class may be completely
incidental if it comes from a trait (see
https://bugs.php.net/bug.php?id=77470). The trait does not control in which
classes it may be used and which names those classes may have.

Of course, porting of legacy code is a legitimate concern. I think the
relevant question in that regard is: How likely is it that people will port
code directly from PHP 5 to PHP 8, without ever running it on PHP 7, where
this generates deprecation notices? Not very, I think.

Finally, it should be mentioned that finding old style constructors is
trivial with static analysis, and I believe that a lot of code style
checker and analyzers already support this functionality since the release
of PHP 7.0.

Nikita

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## #103894 — Pierre Joye — 2019-01-30T11:55:39+00:00

URL: https://externals.io/message/103888#103894 · In reply to: #103892

> Am 30.01.2019 um 12:15 schrieb Pierre Joye:
> > […]
> well.
>
> The no_php4_constructor fixer of php-cs-fixer has been able to
> automatically migrate old-style constructors for years.
>


even better then :)

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## #103896 — Larry Garfield — 2019-01-30T15:30:57+00:00

URL: https://externals.io/message/103888#103896 · In reply to: #103893

> 
> > […]
> 
> First of all, it is probably important to note that the RFC for this (
> https://wiki.php.net/rfc/remove_php4_constructors) explicitly specifies
> that in PHP 8 methods with the same name as the class are interpreted as
> ordinary methods and no warning or error is thrown. I've CC'd Levi and
> Andrea, who authored this RFC.
> 
> I think as an end goal, what the RFC specifies is preferable for a number
> of reasons:
> 
>  * You should be able to call your methods whatever you like. PHP only
> reserves the __ prefix for itself.
>  * The behavior is consistent with classes inside namespaces, where methods
> with the same name as the class are treated as normal methods for a long
> time already.
>  * The fact that a method has the same name as the class may be completely
> incidental if it comes from a trait (see
> https://bugs.php.net/bug.php?id=77470). The trait does not control in which
> classes it may be used and which names those classes may have.

Every Drupal 7 or 8 site includes classes that have a method name the same as 
the class name, on the assumption that it's safe to do for a normal method in 
current PHP versions.  Making that suddenly a Fatal would be, er, bad. :-)

As others have noted, this is easily solved with static analysis tools.  
There's been discussion of WP moving to a PHP 7-based version of PHP sometime 
this year (no promises, but that's the scuttlebutt), which would let them 
convert to __construct() universally and safely well before PHP 8 becomes an 
issue.

--Larry Garfield

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## #103897 — Andreas Heigl — 2019-01-30T15:38:33+00:00

URL: https://externals.io/message/103888#103897 · In reply to: #103896

Am Mittwoch, den 30.01.2019, 09:30 -0600 schrieb Larry Garfield:
> 
> > […]
> 
> Every Drupal 7 or 8 site includes classes that have a method name the
> same as 
> the class name, on the assumption that it's safe to do for a normal
> method in 
> current PHP versions.  Making that suddenly a Fatal would be, er,
> bad. :-)
> 
> As others have noted, this is easily solved with static analysis
> tools.  
> There's been discussion of WP moving to a PHP 7-based version of PHP
> sometime 
> this year (no promises, but that's the scuttlebutt), which would let
> them 
> convert to __construct() universally and safely well before PHP 8
> becomes an 
> issue.

AFAIK WP requires PHP5 already as the minimum PHP-Version. And AFAIK
__construct worked with that as well. So there should be no need to
wait for PHP7 readiness in WordPress to tackle this issue. 

Replacing the function-name-as-class-name constructors with __construct
should be possible without a BC-break already. Even with PHP 5.0 as a
min-requirement.

Or am I missing something?

Cheers

Andreas
                                                              ,,,
      
                                                       (o o)
+--------
-------------------------------------------------ooO-(_)-Ooo-+
| Andreas
Heigl                                                       |
| mailto:
andreas@heigl.org                  N 50°22'59.5" E 08°23'58" |
| 
http://andreas.heigl.org                       http://hei.gl/wiFKy7 |
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| 
http://hei.gl/root-ca                                               |
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## #103898 — Nikita Popov — 2019-01-30T15:43:31+00:00

URL: https://externals.io/message/103888#103898 · In reply to: #103897

>
>
> Am Mittwoch, den 30.01.2019, 09:30 -0600 schrieb Larry Garfield:
> > […]
>
> AFAIK WP requires PHP5 already as the minimum PHP-Version. And AFAIK
> __construct worked with that as well. So there should be no need to
> wait for PHP7 readiness in WordPress to tackle this issue.
>
> Replacing the function-name-as-class-name constructors with __construct
> should be possible without a BC-break already. Even with PHP 5.0 as a
> min-requirement.
>
> Or am I missing something?
>

That's correct. The standard pattern is to do something like this:

class Foobar {
    public function __construct($args) { ... }
    public function Foobar($args) { $this->__construct($args); }
}

This ensures BC even for cases where people are explicitly calling
Foobar::Foobar() for some reason (e.g. because they don't know that
parent::__construct() can be used even if the parent constructor is not
named __construct).

WordPress does use this pattern for their constructors. The original
problem that Dmitry ran into is that WordPress 4.1 was released one year
before PHP 7, so they obviously didn't do this constructor migration at
that point in time yet.

Nikita