sfLuceneHelper.php's add_highlight_qs() function builds its query string like so:
$query .= 'sf_highlight=' . implode($keywords, ' ') . $suffix;
Notice that 'sf_highlight' is hardcoded into the query string. This causes the highlighting to break if you've over-written this value in the filters.yml file with something like this:
highlight:
class: sfLuceneHighlightFilter
param:
highlight_qs: highlight
... since this is value is not respected in the add_highlight_qs() function (the highlighter looks for "highlight" while the query string is still using "sf_highlight"). I don't think it's possible (easily) to load the filters.yml params into another part of the application, so it may make more sense to put this value into the plugin's app.yml so that you can access it from both the filter and the helper. This way, the above function could be something like:
$query .= sfConfig::get('app_lucene_highlight_qs').'=' . implode($keywords, ' ') . $suffix;
... currently the only way around this is to manually define routes in routing.yml that re-map the sf_highlight to another name for the url.
