[RFC] [Discussion] Debugable enums

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

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