[Mediawiki-l] Extension help: why is text appearing twice?

[Daniel Barrett]

Jim Hu writes:
>I suspect that dividing by zero doesn't crash, I bet it sends an  
>error to the log.
>When I want to check that execution got somewhere by crashing I use  
>exit;

Even using exit produces no effect in the OutputPageBeforeHTML hook
function. I think it's just not being executed.
Here is the example again:

$wgHooks['OutputPageBeforeHTML'][] = 'vpHookOutput';

function vpHookOutput(&$parserOutput, &$text) {
  exit(5);
}

The page still displays normally.

Sigh.
DanB