Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:123373
Precedence: bulk
MIME-Version: 1.0
References: <CAAX=eQNH0xyoRkMDThvG_aNS5Hub3tFD52v4PY3OZKT_zWaMmg@mail.gmail.com>
 <CAPzBOBN1M3H-ueqUtzfb_HPv2jZeDaYVTvXideVnx9QYG6LKeA@mail.gmail.com>
 <CAAX=eQPiRs0sq5z2xdtfV9bnf0waV6O+QaAUEfcM90Pwf3+M=g@mail.gmail.com>
 <878c09ca-860e-4c0c-85ae-2cd0246cda3c@rwec.co.uk> <5014b401-6341-44c6-a16e-f453ab52220c@app.fastmail.com>
 <47E8FDF4-9805-4A0B-A2E1-55CF8721253E@rwec.co.uk> <133158d0-1371-4b7c-a2f4-242bfe99ce10@app.fastmail.com>
In-Reply-To: <133158d0-1371-4b7c-a2f4-242bfe99ce10@app.fastmail.com>
Date: Mon, 20 May 2024 14:41:09 -0300
Message-ID: <CAGS0MVDgDoU1TVdhjvxfDhcEymFtt0d0qtb67Bw8b5RtXGsO4w@mail.gmail.com>
Subject: Re: [PHP-DEV] [DISCUSSION] Checking uninitialized class properties
To: php internals <internals@lists.php.net>
Content-Type: multipart/alternative; boundary="0000000000000b9d410618e637dd"
From: ericklima.comp@gmail.com (Erick de Azevedo Lima)

--0000000000000b9d410618e637dd
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

> All of which is to say that, yes, there are use cases for an "is this
property initialized" check that is less fugly than the get_object_vars()
hack I have to rely on now.

I'd like to see this:

if ($objectVar->property is uninitialized) {
...
}

or/and:

if ($objectVar->property is initialized) {
...
}

--
Erick de Azevedo Lima

Em seg., 20 de mai. de 2024 =C3=A0s 14:28, Larry Garfield <larry@garfieldte=
ch.com>
escreveu:

> On Sat, May 18, 2024, at 5:41 PM, Rowan Tommins [IMSoP] wrote:
> > On 18 May 2024 17:13:49 BST, Larry Garfield <larry@garfieldtech.com>
> wrote:
> >>However, that breaks down with readonly properties, which are not
> allowed to have a sentinel.  Uninitialized is their sentinel, for better =
or
> worse.
> >
> > Sorry, I don't understand this statement at all. A readonly property
> > can be set to PatchState::KeepCurrentValue just like any other. If the
> > intention is that that state will be overwritten with an actual value
> > later, then it's not a readonly property.
> >
> > I guess you have some different scenario in mind?
> >
> >
> >> And as I noted earlier in the thread, when writing a serializer or
> other dynamic systems (an ORM probably would have the same issue), you
> really need to be able to differentiate between null and uninitialized.
> Even if you think the uninitialized value is a sign of an error, it's
> coming from code you don't control so you have to be able to handle it
> somehow.
> >
> > If a property is uninitialized, the object is in an invalid state, and
> > attempting to read that property gives an error. That's by design, and
> > as it should be.
> >
> > Are you saying that you want to be able to detect the error before it
> > happens? Why?
>
> For context, remember I maintain a serializer library, so I have to
> support objects that may indeed be in an invalid state, and depending on
> the incoming data may not be able to guarantee an object is in a valid
> state.  I have to do everything via reflection and/or visibility-busting
> closures.  I also maintain an attributes library that, necessarily, has
> multiple methods that get called post-constructor before the object is
> "ready."  Admittedly neither of these are common cases, but neither are
> they invalid cases.
>
> Readonly's current design, and the (IMO, very bad) support from SA tools,
> works on the assumption that your readonly properties are 1. Based on
> constructor params; 2. are always guaranteed set after the constructor.
> While those are true in the majority case, they're not true in the
> universal case.
>
> IOW, "this readonly property is not set by the time the constructor is
> done, so your object is invalid, so your argument is invalid" is not a fa=
ir
> or accurate statement.  And even then, lots of code needs to be able to
> inspect an object to determine if it is valid or not, even if just to giv=
e
> the user a better error message than "Oops, you tried to read an
> uninitialized property, we gonna crash now."  (As noted, I maintain
> multiple such libraries.  ORMs would be the other big use case, I think.)
>
> All of which is to say that, yes, there are use cases for an "is this
> property initialized" check that is less fugly than the get_object_vars()
> hack I have to rely on now.
>
> --Larry Garfield
>

--0000000000000b9d410618e637dd
Content-Type: text/html; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

<div dir=3D"ltr"><div>&gt; All of which is to say that, yes, there are use =
cases for an &quot;is this=20
property initialized&quot; check that is less fugly than the=20
get_object_vars() hack I have to rely on now.=C2=A0 <br></div><div><br></di=
v><div>I&#39;d like to see this:</div><div><br></div><div>if ($objectVar-&g=
t;property is uninitialized) {</div><div>...<br></div><div>}</div><div><br>=
</div><div>or/and:<br><br><div>if ($objectVar-&gt;property is initialized) =
{</div><div>...<br></div><div>}</div></div><div><br></div><div>--</div><div=
>Erick de Azevedo Lima<br></div></div><br><div class=3D"gmail_quote"><div d=
ir=3D"ltr" class=3D"gmail_attr">Em seg., 20 de mai. de 2024 =C3=A0s 14:28, =
Larry Garfield &lt;<a href=3D"mailto:larry@garfieldtech.com" target=3D"_bla=
nk">larry@garfieldtech.com</a>&gt; escreveu:<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 Sat, May 18, 2024, at 5:41 PM, Rowan Tommin=
s [IMSoP] wrote:<br>
&gt; On 18 May 2024 17:13:49 BST, Larry Garfield &lt;<a href=3D"mailto:larr=
y@garfieldtech.com" target=3D"_blank">larry@garfieldtech.com</a>&gt; wrote:=
<br>
&gt;&gt;However, that breaks down with readonly properties, which are not a=
llowed to have a sentinel.=C2=A0 Uninitialized is their sentinel, for bette=
r or worse.<br>
&gt;<br>
&gt; Sorry, I don&#39;t understand this statement at all. A readonly proper=
ty <br>
&gt; can be set to PatchState::KeepCurrentValue just like any other. If the=
 <br>
&gt; intention is that that state will be overwritten with an actual value =
<br>
&gt; later, then it&#39;s not a readonly property. <br>
&gt;<br>
&gt; I guess you have some different scenario in mind?<br>
&gt;<br>
&gt;<br>
&gt;&gt; And as I noted earlier in the thread, when writing a serializer or=
 other dynamic systems (an ORM probably would have the same issue), you rea=
lly need to be able to differentiate between null and uninitialized.=C2=A0 =
Even if you think the uninitialized value is a sign of an error, it&#39;s c=
oming from code you don&#39;t control so you have to be able to handle it s=
omehow.<br>
&gt;<br>
&gt; If a property is uninitialized, the object is in an invalid state, and=
 <br>
&gt; attempting to read that property gives an error. That&#39;s by design,=
 and <br>
&gt; as it should be.<br>
&gt;<br>
&gt; Are you saying that you want to be able to detect the error before it =
<br>
&gt; happens? Why?<br>
<br>
For context, remember I maintain a serializer library, so I have to support=
 objects that may indeed be in an invalid state, and depending on the incom=
ing data may not be able to guarantee an object is in a valid state.=C2=A0 =
I have to do everything via reflection and/or visibility-busting closures.=
=C2=A0 I also maintain an attributes library that, necessarily, has multipl=
e methods that get called post-constructor before the object is &quot;ready=
.&quot;=C2=A0 Admittedly neither of these are common cases, but neither are=
 they invalid cases.<br>
<br>
Readonly&#39;s current design, and the (IMO, very bad) support from SA tool=
s, works on the assumption that your readonly properties are 1. Based on co=
nstructor params; 2. are always guaranteed set after the constructor.=C2=A0=
 While those are true in the majority case, they&#39;re not true in the uni=
versal case.<br>
<br>
IOW, &quot;this readonly property is not set by the time the constructor is=
 done, so your object is invalid, so your argument is invalid&quot; is not =
a fair or accurate statement.=C2=A0 And even then, lots of code needs to be=
 able to inspect an object to determine if it is valid or not, even if just=
 to give the user a better error message than &quot;Oops, you tried to read=
 an uninitialized property, we gonna crash now.&quot;=C2=A0 (As noted, I ma=
intain multiple such libraries.=C2=A0 ORMs would be the other big use case,=
 I think.)<br>
<br>
All of which is to say that, yes, there are use cases for an &quot;is this =
property initialized&quot; check that is less fugly than the get_object_var=
s() hack I have to rely on now.=C2=A0 <br>
<br>
--Larry Garfield<br>
</blockquote></div>

--0000000000000b9d410618e637dd--