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[RFC] [Discussion] Debugable enums

php.internals

Daniel Scherzer

172 days ago

Hi internals,

I'd like to start the discussion for a new RFC about removing the
prohibition on __debugInfo() methods on enums.

* RFC: https://wiki.php.net/rfc/debugable-enums
* Implementation: https://github.com/php/php-src/pull/21425

This is a replacement of my earlier RFC to allow __toString() based on the
feedback in that discussion, see
https://news-web.php.net/php.internals/129540.

Thanks,
-Daniel

Larry Garfield

172 days ago

On Thu, Mar 12, 2026, at 7:05 PM, Daniel Scherzer wrote:

> Hi internals,
>
> I'd like to start the discussion for a new RFC about removing the
> prohibition on __debugInfo() methods on enums.
>
> * RFC: https://wiki.php.net/rfc/debugable-enums
> * Implementation: https://github.com/php/php-src/pull/21425
>
> This is a replacement of my earlier RFC to allow __toString() based on
> the feedback in that discussion, see
> https://news-web.php.net/php.internals/129540.
>
> Thanks,
> -Daniel

I'm not entirely sure this has much value, but it also seems to not have much downside.  The main argument I could see for holding off is that whenever it is we get to ADTs, we may want a more complex default implementation.  But that would still presumably allow being overridden, like any other class, so it doesn't seem like a landmine to me.  This doesn't have the same semantic issues that __toString() has (and have been discussed elsewhere).

--Larry Garfield

Ilija Tovilo

171 days ago

Hi Daniel

On Fri, Mar 13, 2026 at 1:06 AM Daniel Scherzer
<daniel.e.scherzer@gmail.com> wrote:

>
> I'd like to start the discussion for a new RFC about removing the prohibition on __debugInfo() methods on enums.
>
> * RFC: https://wiki.php.net/rfc/debugable-enums
> * Implementation: https://github.com/php/php-src/pull/21425

The RFC currently only mentions:

> var_dump(Foo::Bar); // produces an array with "Bar is a case of the Foo enum"

But it would be good for it to spell out the full output for the
examples. From the implementation, I can see:

> object(Foo)#%d (1) {
>  [0]=>
>  string(14) "Foo::Bar = Baz"
> }

I think the enum(Foo::Bar) header should be preserved. If the user
wants to print some ancillary data for some reason, I wouldn't object
to that.

Ilija

Daniel Scherzer

170 days ago

On Sun, Mar 15, 2026 at 11:01 AM Ilija Tovilo <tovilo.ilija@gmail.com>
wrote:

> Hi Daniel
>
> On Fri, Mar 13, 2026 at 1:06 AM Daniel Scherzer
> <daniel.e.scherzer@gmail.com> wrote:
> >
> > I'd like to start the discussion for a new RFC about removing the
> prohibition on __debugInfo() methods on enums.
> >
> > * RFC: https://wiki.php.net/rfc/debugable-enums
> > * Implementation: https://github.com/php/php-src/pull/21425
>
> The RFC currently only mentions:
>
> > var_dump(Foo::Bar); // produces an array with "Bar is a case of the Foo
> enum"
>
> But it would be good for it to spell out the full output for the
> examples.
>

Done, examples now show the full output

> From the implementation, I can see:
>
> > object(Foo)#%d (1) {
> >  [0]=>
> >  string(14) "Foo::Bar = Baz"
> > }
>
> I think the enum(Foo::Bar) header should be preserved. If the user
> wants to print some ancillary data for some reason, I wouldn't object
> to that.
>

Done, the header is now preserved. I also removed the object handler
identifier, which I don't think is as needed with enums.

Based on my understanding of the RFC policy (
https://github.com/php/policies/blob/main/feature-proposals.rst), this
qualifies as a major change, so there is now a cooldown period of 14 days
before the earliest that a vote could start.

-Daniel

Tim Düsterhus

169 days ago

Hi

Am 2026-03-13 01:05, schrieb Daniel Scherzer:

> * RFC: https://wiki.php.net/rfc/debugable-enums
> * Implementation: https://github.com/php/php-src/pull/21425

Thank you. Similarly to Larry, I don't see much reason in favor, but
also no reason against allowing `__debugInfo()`.

I noticed that the title of the voting widget did not render properly
(it showed “Default title”). It seems the `<php>` tags were at fault. I
have removed the tags and also added a “Primary Vote requiring a 2/3
majority to accept the RFC:” note as required by policy and shown in the
template.

Best regards
Tim Düsterhus

Daniel Scherzer

154 days ago

On Thu, Mar 12, 2026 at 5:05 PM Daniel Scherzer <daniel.e.scherzer@gmail.com>
wrote:

> Hi internals,
>
> I'd like to start the discussion for a new RFC about removing the
> prohibition on __debugInfo() methods on enums.
>
> * RFC: https://wiki.php.net/rfc/debugable-enums
> * Implementation: https://github.com/php/php-src/pull/21425
>
> This is a replacement of my earlier RFC to allow __toString() based on the
> feedback in that discussion, see
> https://news-web.php.net/php.internals/129540.
>

This email is a notice that I intend to open the vote on this RFC in the
next few days, barring any unexpected developments.

-Daniel