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Date: Mon, 28 Jun 2021 11:22:17 -0500
To: "php internals" <internals@lists.php.net>
Content-Type: text/plain
Subject: Re: [PHP-DEV] Re: [RFC] Readonly properties
From: larry@garfieldtech.com ("Larry Garfield")

On Mon, Jun 28, 2021, at 11:17 AM, Nicolas Grekas wrote:
> > > I'd like to open the discussion on readonly properties:
> > > https://wiki.php.net/rfc/readonly_properties_v2
> > >
> > > This proposal is similar to the
> > > https://wiki.php.net/rfc/write_once_properties RFC that has been
> > declined
> > > previously. One significant difference is that the new RFC limits the
> > scope
> > > of initializing assignments. I think a key mistake of the previous RFC
> > was
> > > the confusing "write-once" framing, which is both technically correct and
> > > quite irrelevant.
> > >
> > > Please see the rationale section (
> > > https://wiki.php.net/rfc/readonly_properties_v2#rationale) for how this
> > > proposal relates to other RFCs and alternatives.
> > >
> >
> > I plan to open voting on this RFC soon. I don't think there's anything
> > technical left to address here, the discussion mostly comes down to a value
> > judgement. I think everyone has made their position regarding that clear...
> >
> 
> Actually, we talked off the list about a way to possibly make this work
> with __clone():
> 
> We could allow __clone to have one argument, the object being cloned. And
> when the signature declares this argument, then all readonly properties
> would be set as uninitialized on $this.
> 
> A typical __clone function would look like this with readonly properties:
> function __clone(object $original)
> {
>     $this->readonlyProp = clone $original->readonlyProp;
> }
> 
> That would turn my vote into a +1 if that could be made to work!

That sounds like it would support deep cloning, but not with-er methods.  There's no way to provide a changed value.  It also would mean a lot of work on larger objects to transfer across all the properties.  I don't really see what this would add.

--Larry Garfield