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Date: Mon, 4 May 2026 13:04:43 -0700
Message-ID: <CALaXqqRc+ebD8_nHJu-nn3e6oudo_NF1pEAENKG4y+7FsNAarQ@mail.gmail.com>
Subject: Re: [PHP-DEV] Pre-RFC discussion about adding friendship to PHP
To: Larry Garfield <larry@garfieldtech.com>
Cc: php internals <internals@lists.php.net>
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From: daniel.e.scherzer@gmail.com (Daniel Scherzer)

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On Mon, May 4, 2026 at 12:50=E2=80=AFPM Larry Garfield <larry@garfieldtech.=
com>
wrote:

> On Wed, Apr 29, 2026, at 12:30 PM, Daniel Scherzer wrote:
> > Hi internals,
> >
> > I'd like to add support for friendship in PHP.
> >
> > -Daniel
>
> There was a lot of related discussion around module/package/file
> visibility not too long ago that is also worth reviewing.  Currently I am
> highly skeptical of friend classes, as I believe module-level visibility =
is
> more useful than class-level, in general.
>

I think that perfect should not be the enemy of good, and this also lays
the groundwork for namespace-level friends in the future. We shouldn't wait
for a potential future "module-level visibility" if we can have friends now=
.


>
> That said, were we to go this route, I agree that keywords would be the
> way to go for the reasons given in the blog post.  Also, there's some
> plumbing already i place via aviz, at least for properties.  In concept,
> the following should be possible:
>
> class User {
>   friend UserFactory;
>
>   public friend(set) string $name;
> }
>

I think having friends that can access everything is more helpful than a
new level of visibility - if you declare a class as a friend you already
know that the class exists and wants to access private implementation
details, so you can trust it to upload the class invariants.

-Daniel

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<div dir=3D"ltr"><div dir=3D"ltr"><br></div><div class=3D"gmail_quote gmail=
_quote_container"><div dir=3D"ltr" class=3D"gmail_attr">On Mon, May 4, 2026=
 at 12:50=E2=80=AFPM Larry Garfield &lt;<a href=3D"mailto:larry@garfieldtec=
h.com">larry@garfieldtech.com</a>&gt; wrote:<br></div><blockquote class=3D"=
gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(20=
4,204,204);padding-left:1ex">On Wed, Apr 29, 2026, at 12:30 PM, Daniel Sche=
rzer wrote:<br>
&gt; Hi internals,<br>
&gt;<br>
&gt; I&#39;d like to add support for friendship in PHP.<br>
&gt;<br>
&gt; -Daniel<br>
<br>
There was a lot of related discussion around module/package/file visibility=
 not too long ago that is also worth reviewing.=C2=A0 Currently I am highly=
 skeptical of friend classes, as I believe module-level visibility is more =
useful than class-level, in general.<br></blockquote><div><br></div><div>I =
think that perfect should not be the enemy of good, and this also lays the =
groundwork for namespace-level friends in the future. We shouldn&#39;t wait=
 for a potential future &quot;module-level visibility&quot; if we can have =
friends now.</div><div>=C2=A0</div><blockquote class=3D"gmail_quote" style=
=3D"margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding=
-left:1ex">
<br>
That said, were we to go this route, I agree that keywords would be the way=
 to go for the reasons given in the blog post.=C2=A0 Also, there&#39;s some=
 plumbing already i place via aviz, at least for properties.=C2=A0 In conce=
pt, the following should be possible:<br>
<br>
class User {<br>
=C2=A0 friend UserFactory;<br>
<br>
=C2=A0 public friend(set) string $name;<br>
}<br></blockquote><div><br></div><div>I think having friends that can acces=
s everything is more helpful than a new level of visibility - if you declar=
e a class as a friend you already know that the class exists and wants to a=
ccess private implementation details, so you can trust it to upload the cla=
ss invariants.</div><div><br></div><div>-Daniel</div></div></div>

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