How to debug

Help others to help you

Sometimes things go wrong. In many cases the user is then confronted with cryptic or no error messages at all. This page provides help about getting more information about what exactly went wrong, so it can be fixed quickly. This is especially important when asking for help on locations like community.bluespice.com.

Additional information can also be found at "Manual:How to debug" on MediaWiki.org.

Check for sensitive informationMost of the techniques described here will output very detailed information about the error, but also about the system and the context. The output may contain sensitive information like usernames, passwords, pathes, access-keys and many more. Before posting any information retrieved by this kind of debugging on a public location (like community.bluespice.com), make sure to redact all potential sensitive information!

Generic information

In general it is a good idea to provide additional context information about the error. Usually this information is easily to access/gather by the one who reports an error and very valueable to anyone trying to help.

Such information can be

• Browser used (Firefox, Chrome, Edge, ...), ideally with the version
• URLs (which page the error occurs on, additional parameters that may play into the error)
• User permission level or role (admin, reader, editor, reviewer, ...)

Again: Be careful if the shared information contains sensible data and redact it if required.

Server side debugging

There are various ways to get more information about errors by changing some configuration on the server side.

Wiki application

Enable detailed error reporting

Within you LocalSettings.php file, please add the following lines:

$GLOBALS['wgShowSQLErrors'] = true;
$GLOBALS['wgDebugDumpSql']  = true;
$GLOBALS['wgShowExceptionDetails'] = true;
$GLOBALS['wgShowDBErrorBacktrace'] = true;

This will turn error messages like internal_api_error_DBQueryError into a more detailed stack of program calls, including database queries and responses.

General debug log

Sometimes it can be useful to see all debugging information the application produces. To enable this general debug log please add the following lines within you LocalSettings.php file:

if ( isset( $_GET['dodebuglog'] ) ) {
    $GLOBALS['wgDebugLogFile'] = "$IP/cache/debug.log";
}

Be aware that this configuration is set conditionally. It will only be used if the URL accessed in the browser contains some query string like dodebuglog=1. This is to allow a more isolated debug log file. Otherwise other requests (like calls to the load.php entrypoint for CSS and JS content) may also add into this file, which makes analysis more difficult.

Clientside output of serverside logs

Can be enabled using $wgDebugToolbar

Example:

$GLOBALS['wgDebugToolbar'] = isset( $_GET['dodebuglog'] )

Client side debugging

Many errors occur only on the client and server side debugging will not help. In such cases the webbrowser can be used to retrieve more information.

Browser development tools

Most modern browsers have sophisticated development tools. Usually they can be accessed by pressing the F12 key on the keyboard.

JavaScript console

When some interface element (button, dialog, ...) does not behave like it should, it is usually worth checking the browsers JavaScript console.

Nothing listed?Sometimes it may be required to re-do the action that lead to the error with open console rather than opening it later.

Example:

One can click the link on the right side of the line to see the location of where the error has emerged from.

Example:

Network panel

Sometimes network communication in the background of the application fails. In such cases, the "Network" panel of the browsers developer tools may reveal more information.

The error is also shown in the "Console" tab.

Example:

When in the "Network" panel, one can select the faulty request from the list to get more information.

Example:

The various tabs "Header", "Payload", "Response", etc. can provide useful information. When reporting such an issue, you can just "copy" the information using the context menu.

Example:

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