R – How to create an error handling page in ICEfaces (with Facelets)

I think this largely depends on your JSF implementation. I've heard that some will render blank screens.

The one we were using would throw error 500's with a stack trace. Other times out buttons wouldn't work without any error for the user. This was all during our development phase.

But the best advice I can give you is to catch the exceptions and log them in an error log so you have the stack trace for debugging later. For messages that we couldn't do anything about like a backend failing we would just add a fatal message to the FacesContext that gets displayed on the screen and log the stack trace.

For syntax errors, you need to enable error display in the php.ini. By default these are turned off because you don't want a "customer" seeing the error messages. Check this page in the PHP documentation for information on the 2 directives: error_reporting and display_errors. display_errors is probably the one you want to change. If you can't modify the php.ini, you can also add the following lines to an .htaccess file:

php_flag  display_errors        on
php_value error_reporting       2039

You may want to consider using the value of E_ALL (as mentioned by Gumbo) for your version of PHP for error_reporting to get all of the errors. more info

3 other items: (1) You can check the error log file as it will have all of the errors (unless logging has been disabled). (2) Adding the following 2 lines will help you debug errors that are not syntax errors:

error_reporting(-1);
ini_set('display_errors', 'On');

(3) Another option is to use an editor that checks for errors when you type, such as PhpEd. PhpEd also comes with a debugger which can provide more detailed information. (The PhpEd debugger is very similar to xdebug and integrates directly into the editor so you use 1 program to do everything.)

Cartman's link is also very good: http://www.ibm.com/developerworks/library/os-debug/