Identifying bugs an thus better reporting of bugs can be achieved by:
Stack traces (PHP)
Stack traces (example) supply extra information typically associated with errors/exceptions that help developers figure out what is going wrong. Thus they are often needed in order to get bugs fixed. By default stack traces are not shown on a MediaWiki install as this is not something desired when running a production wiki. However if you are running into an issue and the developer needs more information, please follow the instructions described below to get a stack trace if an the error occurs on your wiki. After retrieving this information you should again remove or comment out the settings.
1) On the top of your wiki's LocalSettings.php file (below the first comment block), add
error_reporting( -1 ); // catch all PHP errors ini_set( 'display_errors', 1 ); // show the PHP errors caught
2) At the very end of your wiki's LocalSettings.php file, add
$wgShowExceptionDetails = true; $wgShowSQLErrors = true; $wgDebugComments = true; $wgLogQueries = true; $wgDebugDumpSql = true; $wgDevelopmentWarnings = true; $wgDebugProfiling = true; $wgDebugTimestamps = true; $wgResourceLoaderDebug = true; $wgDebugToolbar = true;
Sometimes it can also be helpful to enable the ResourceLoader debug mode.
Help:Identifying bugs en 1.8.0