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HEAD, include(_once), bug in variable declaration

php.internals

Pierre-Alain Joye

22 years ago

Hello,

Having the scripts pasted below:

include_once fails to declare the variable 'foo'. Replace include_once
by include and it works. I got the same behavior using require and
require_once.

Am I wrong to see that as a bug?

inc.php
--------
<?php
$foo = "var from include";
?>

testinc.php
-----------
<?php

function getFoo()
{
static $calls=0;
include_once 'inc.php';
$calls++;
echo "calls:$calls\n";
return $foo;
}
echo getFoo() . "\n";
echo getFoo() . "\n";
?>

hth

pierre

Pierre-Alain Joye

22 years ago

On Wed, 18 Feb 2004 15:27:56 +0100
paj@pearfr.org (Pierre-Alain Joye) wrote:

> Hello,
>
> Having the scripts pasted below:
>
> include_once fails to declare the variable 'foo'. Replace include_once
> by include and it works. I got the same behavior using require and
> require_once.

To be precised: it fails to declare the variable on the 2nd call. The
1st call works.

pierre

Antony Dovgal

22 years ago

On Wed, 18 Feb 2004 15:39:10 +0100
Pierre-Alain Joye <paj@pearfr.org> wrote:

> On Wed, 18 Feb 2004 15:27:56 +0100
> paj@pearfr.org (Pierre-Alain Joye) wrote:
>
> > Hello,
> >
> > Having the scripts pasted below:
> >
> > include_once fails to declare the variable 'foo'. Replace include_once
> > by include and it works. I got the same behavior using require and
> > require_once.
>
> To be precised: it fails to declare the variable on the 2nd call. The
> 1st call works.

because it doesn't really include this file on the 2nd call.

[quote]
include_once() should be used in cases where the same file might be included and evaluated more than once during a particular execution of a script, and you want to be sure that it is included exactly once to avoid problems with function redefinitions, variable value reassignments, etc.
[/quote]

thus, this is expected behaviour.

---
WBR,
Antony Dovgal aka tony2001
tony2001@phpclub.net

Hartmut Holzgraefe

22 years ago

Pierre-Alain Joye wrote:

> Hello,
>
> Having the scripts pasted below:
>
> include_once fails to declare the variable 'foo'. Replace include_once
> by include and it works. I got the same behavior using require and
> require_once.
>
> Am I wrong to see that as a bug?
>
> inc.php
> --------
> <?php
> $foo = "var from include";
> ?>
>
> testinc.php
> -----------
> <?php
>
> function getFoo()
> {
>         static $calls=0;
>         include_once 'inc.php';
>         $calls++;
>         echo "calls:$calls\n";
>         return $foo;
> }
> echo getFoo() . "\n";
> echo getFoo() . "\n";
> ?>
>

it works for the first call to getFoo(),
on any following call include_once
will ignore "inc.php" as it was already
included before, and as $foo is a local
variable to getFoo() it won't exist in
any but the first call

remember that in PHP include is evaluated
at runtime, not at compile time ...

--
Hartmut Holzgraefe  <hartmut@php.net>

Pierre-Alain Joye

22 years ago

On Wed, 18 Feb 2004 15:44:10 +0100
hartmut@php.net (Hartmut Holzgraefe) wrote:

> it works for the first call to getFoo(),
> on any following call include_once
> will ignore "inc.php" as it was already
> included before, and as $foo is a local
> variable to getFoo() it won't exist in
> any but the first call
>
> remember that in PHP include is evaluated
> at runtime, not at compile time ...

Thanks for the reminder :) I thought about that at the first source of
the problem, but:

It works with php4. For instance this is widely used to include a given
file on demand, and only on demand.

I thought that in the context of getFoo (lost between 2 calls), it
should include it again.

In this simple case, it is not a problem, there is no global
"pollution". But in the case the included files contains a
class/function definition, you run in troubles. That's why I think the
behavioir should remain the same as with php4.

An alternative is to split all possible runtime datas to a different
file and not in the same file as the class/function declaration. But in
both cases that will break a lot of scripts around.

hth

pierre

Pierre-Alain Joye

22 years ago

Forget it. That works the same way in php4.

Sorry for the noise :)

pierre