Are you sure you want to re-index? Needed

should there be a threshold? For a smaller site (e.g. 1000 nodes) this is a pretty minor action.

I think adding a confirmation form is in line with normal Drupal usage.

Peter - let's avoid the threshold. Too hard to tell when it's appropriate and when not, and it would add extra code for no good reason.

I'm overall neutral on the feature request, but I do think it is probably more in line with typical Drupal behavior, and there's request for the feature, thus I'm inclined to commit to both branches pending review.

@robert - it's ok with me

Committed to 6.1 and 6.2.

 function apachesolr_clear_index($form, &$form_state) {
+  return apachesolr_comfirm_clear_index($form, $form_state);
+}

should maybe be

 function apachesolr_clear_index($form, &$form_state) {
+  return apachesolr_clear_index_confirm($form, $form_state);
+}