Missing signature violation warnings suck. View as Markdown

Em Qua, 2008-04-09 às 11:27 +0200, Derick Rethans escreveu:

I don't know who removed this check, but please put it back
in!

Hi Derick,
it looks has been introduced by this patch suggested and discussed in
that thread:
http://marc.info/?l=php-internals&m=120430609612237&w=2

--
Regards,
Felipe Pena.

Derick Rethans wrote:

I've been working on some code, while developing on PHP 5.3. The code
resembles the following structure:

<?php
interface ezcSearchQuery
{
public function limit( $limit, $offset = '' );
}

class ezcSearchFindQuerySolr implements ezcSearchQuery
{
public function limit( $limit = 10, $offset = 0 )
{
$this->limit = $limit;
$this->offset = $offset;
}
}
?>

No problems at all while development, no warnings, no errors. Now when I
deployed this on a PHP 5.2 machine it bombed out, with the following
correct message:

I disagree, the error message with 5.2 was wrong IMHO, see below for reason.

Fatal error: Declaration of ezcSearchFindQuerySolr::limit() must be
compatible with that of ezcSearchQuery::limit() in /tmp/tmp/index.php on
line 11

And this really sucks. I made a mistake in my code (wrongly implemented
interface) and I get no warning (not even E_STRICT)... and then deploy

Can you elaborate in how your implementation is wrong?
ezcSearchFindQuerySolr accepts the same arguments ezcSearchQuery does so
it is a valid implementation of the interface.

Every user of the ezcSearchQuery interface can be given an instance of
ezcSearchFindQuerySolr and it will work, so the
http://en.wikipedia.org/wiki/Liskov_substitution_principle is fulfilled.

This principle does not mean that all users of a specific implementation
have to be able to be given another implementation of the interface and
be happy with it. You can e.g. have
class ezcOrderedSearchQuery implements ezcSearchQuery
{
public function limit( $limit, $offset = 0, $order = "ASC" )
{
...
}
}

class ezcFilteredSearchQuery implements ezcSearchQuery
{
public function limit( $limit, $offset = 0 )
{
...
}

public function filter( $filter )
{
}

}

... which are in the same boat: ezcOrderedSearchQuery and
ezcFilteredSearchQuery can be used as ezcSearchQuery but not necessarily
the other way around.

• Chris

Hi!

public function limit( $limit, $offset = '' );
public function limit( $limit = 10, $offset = 0 )

No problems at all while development, no warnings, no errors. Now when I
deployed this on a PHP 5.2 machine it bombed out, with the following
correct message:

Fatal error: Declaration of ezcSearchFindQuerySolr::limit() must be
compatible with that of ezcSearchQuery::limit() in /tmp/tmp/index.php on
line 11

Why it's correct? limit() with default can extend limit without default,
since every place you could call ezcSearchFindQuery::limit you also
could call ezcSearchFindQuerySolr::limit. No precondition is
strengthened, so I don't see a problem there.

--
Stanislav Malyshev, Zend Software Architect
stas@zend.com http://www.zend.com/
(408)253-8829 MSN: stas@zend.com