How to debug WordPress correctly?

I’m using a few plugins and UpThemes framework on my new website and if I turn on Wp Debug I can see that there are a few errors related to Deprecated functions (but website is working). What I would like to know is if there is a plugin, a software or a pray (lol) that I can use to know exactly where the deprecated code is so I’ll be able to use the new one.

Which is the plugin/software that you use to debug your plugins, themes?

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What you’re looking for is the Log Deprecated Notices plugin. (Don’t run it on a production site, as it is a direct-to-database log.)

What it’ll do is convert those cryptic messages that are likely to reference has_cap() or some line in functions.php, to what’s actually going on.

The Debug Bar plugin is also nice. It tracks notices of that pageload, using the conversion code from Log Deprecated Notices.

I’ve used Theme Check in the past and found it very good. If I recall correctly, it checks against deprecated functions but most of all it suggests better functions to future-proof your theme, and alerts you when you’re forgetting to implement features which WordPress’ users have learnt to rely on.

The quickest way to do this is just using grep for the function name in it’s theme/plugin folder. If your on windows you can use grepWin or agent ransack/powershell, etc.

Also install debug-bar, it’s a lot nicer to look at.

During theme development you can make debug mode on by changing Debug value to ‘true’ in root config.php

This will keep debug and show error during development.

Zend’s Z-Ray has a theme profiler. Also useful for seeing SQL queries.