Data type inconsistencies in WordPress

Yesterday I tweeted about data type inconsistencies in WordPress plugins, something that has been bothering me for a while now.

Inconsistent data types is quite common in PHP development as it is a "weak typed" language. In PHP version 5.3 and up, you can force the type of some non-scalar function parameters.

Hack further improved on this by introducing type annotations, which allow for PHP code to be explicitly typed on parameters, class member variables and return values. Very cool.

Unfortunately, both improvements can not be used when developing for WordPress. Yet.

Plugin developers, please make sure your functions always return the same data type. If your function returns either a boolean, an array or a string, you are asking for trouble.

If your function returns either a boolean, an array or a string, it smells and you need to refactor.

Either you or someone else working with your code will run into a bug later and wonder why. This is even more important when you are allowing third-party developers to filter your function returns.

We have all seen errors like this far too often..

• Fatal error: Cannot use string offset as an array..
• Warning: strpos() expects parameter 1 to be string, array given..
• Notice: Trying to get property of non-object..

Consistency is so important. In everything.