On the Ibuildings blog today, Harrie Verveer has posted about an interesting quirk he found when working with objects and references:

PHP is a loosely typed language. Most of the time this is very useful because you as a programmer don't have to worry about typecasting: it's done for you. However, on some occasions this can cause some unexpected trouble. [...] In this blog I want to point out what can happen if you try to access object properties by reference when the object is not initialized.

His example shows the problem when it tries to grab a value from an array in a non-existent object by reference. It results in a dyanamically created object (of that type) with an empty array inside of it. It only works when you grab it by reference, but he shares a tip or two about how you can prevent hard to track down issues like this.

If you're a WordPress user and are in the process of an upgrade from PHP4 to PHP5, you might be having a few issues. One problem can be cause by the wp-cache component and this recent post from Shantanu Goel.

The issues range from weird page layouts, to some controls not working, to some errors popping up here and there, and probably your blog not even displaying. This occurs because even though WordPress is PHP5 compatible, some of the plugins you are using might not be.

In his case, it was the wp-cache plugin that was causing the problems. Permissions weren't right to allow it to do its job. This resulted in problems rendering content and with the site acting as it normally would. His solution involved disabling and reenabling the plugin after deleting the cache and lock file the plugin uses.

Matthew Turland has come across an "interesting bug" in PHP's stream wrappers functionality - some strange 404 or 500 HTTP errors in one of his scripts.

I wrote a small script a while back that's gained a surprising amount of popularity thanks to a plug from the site that it posts to. [...] I learned that this [connection from the script] could be done with streams, I attempted to implement it in that fashion, but ran into strange issues where I would get 404 or 500-level HTTP errors rather than the response I was expected.

He eventually found the bug related to his problem (in the 5.2.x branch) but happily notes that it has been corrected and will be patched in the upcoming 5.3 (and 6) branches.

According to this post on the PEAR blog, the first PEAR bug triage is now over:

PEAR's bug tracker hit the 600+ open bugs mark a month ago. [...] So with 600+ open bugs (not including the feature requests), we had to do something. [...] The logical step was to hold our own bug smashing event and see how it works for PEAR.

Back on March 22nd and 23rd (Easter weekend) they hunted for bugs. Several developers showed to help out and many bugs were fixed and they managed to bring the number of open bugs for PEAR down to 547 with the two days of work. There were some milestones reached too:

Thanks to the triage, we are close to reaching two important milestones: Closing bug reports with lower bug ID than 1000 (1 bug left!) and 2000 (5 left).

Michael Kimsal has posted his opinion on why PDO, the database interface layer for PHP, sucks.

Every so often I try to use PDO under PHP5, and every time I run in to basic functionality problems with no ability to find out what's going on under the hood.

He includes a few comments supporting his statement including an issue where a prepare() call didn't work, his frustration with not being able to see what's "under the hood" and the lack of documentation to help with these sorts of issues.

Padraic Brady has pointed out the "new kid in town" when it comes to magazines about PHP - Enterprise PHP:

There is a new PHP magazine called "Enterprise PHP" available in English, German and French which might even console those missing the apparently ill-fated International PHP Magazine. Back before publication the usual tree of suspects led me to being interviewed for the initial edition published a short while back.

The current issue (which you can get for free after a survey) has articles looking at testing your PHP scripts, how "professional" it is to use PHP and the fact that Java is not PHP (wait, isn't that backwards?)

The PHP-GTK Community Site has posted about an issue that's been found with PHP-GTK on a Windows Vista machine that can cause problems with how the OS handles memory (by Wim Stockman).

My work station is WinXp system and my friend where I had to create it for has the new Vista and somewhere over 9000 pictures to be managed. On my system everything worked fine, but on my friends system i always got the error can not open file.

Further testing revealed that it was the OS at fault - Vista wasn't handling the memory usage for the application correctly. When it was run directly from the file explorer (versus in the PHP-GTK console) though, it worked just fine.

Maggie Nelson has pointed out an article in the most recently published edition of php|architect magazine (the February 2008 issue) that's an introduction to database design for programmers (by Mac Newbold).

It's a pretty good article about database design and I think all PHP developers who are just starting to integrate databases in their applications should read it. However, there are a few things I'd like to add and point out.

The "blurb" for the article mentions MySQL, PostgreSQL, Oracle, Microsoft SQL, SQLite and database schemas. You can find out more about this issue, including how to get your own copy, from the php|architect website.

As Cal Evans and others in the PHP community have pointed out, there's a post on Tim Bray's blog (of Sun Microsystems) with his prediction for PHP for the upcoming year:

The short version: PHP will remain popular but its growth will slow, as people get nervous about its maintainability and security stories.

He does mention the two different stances of this statement - the good side (with low entry level, good applications and speed) and the stance he seems to believe in more - that there are just things about PHP and how its handled that could cause major issues down the line.

Be sure to check out the comments for community views on both sides of the story too.

For anyone that's had an issue with getting XDebug to work with the Debian linux distribution, you might want to check out this helpful hint Carsten Lucke has posted about.

This week I started to setup a Debian-based (Etch) web-server with PHP 5.2 in a virtual-machine with VMWare. Part of this setup was getting XDebug2 integrated. It's really awesome and my students definitely need to learn about it. [...] Building went well as usual but when I tried to integrate the extension inside php.ini it was all weird.

His system kept throwing him an error when he tried to load the shared module using the zend_extension directive, hand things happened. Loading it normally worked (so he knew it wasn't the module) and he finally figured out the problem:

But I need to enable it as Zend extension. Whatever. I finally used the full path to xdebug.so to load it [...] that worked.