parse_filters() causes any manually added filters to be lost

can of worms.

for example, if I remove a filter which came from the URL, and then add an alias, that filter would come back

I think this patch is not really the right approach.

this is totally untested, but I think it's a workable approach.

needs some more code comments, but committed to 6.x-1.x for immediate use in the redesign.

FYI: now deployed on d.o and working fine:

http://drupal.org/search/apachesolr_search/signup

Committed this patch to all the active branches.

back to active for code comments.

No longer a bug.

Shouldn't we remove the filter from fields_removed if we add it back with add_filter?

Port my patch to 6.x-2.x and 7.x if patch goes in.

Which version is that patch for? Or it's just cleanup for 6.x-1.x?

It's a fix for all versions, starting with 6.x-1.x

Logic looks fine to me - looks like as much comment changes as anything.

afaikt, the only meaningful change is this, right?

+    // Remove from the record of removed filters.
+    $this->unset_filter($this->fields_removed, $name, $value);

Yes, that's it. I fixed comments so that the two functions are comparable.

Fixed in 6.1, 6.2 and 7.1.

+++ Solr_Base_Query.php
@@ -178,8 +178,12 @@ class Solr_Base_Query implements Drupal_Solr_Query_Interface {
   public function add_filter($field, $value, $exclude = FALSE, $callbacks = array()) {
     $filter = array('#exclude' => $exclude, '#name' => $field, '#value' => trim($value), '#callbacks' => $callbacks);
-    $this->fields[] = $filter;
+    // Record the addition.
     $this->fields_added[] = $filter;
+    // Add to the public list of filters.
+    $this->fields[] = $filter;
+    // Remove from the record of removed filters.
+    $this->unset_filter($this->fields_removed, $name, $value);
   }

$name is undefined in this function. This is causing notices # Notice: Undefined variable: name in SolrBaseQuery->add_filter() (line 191 of /sites/all/modules/apachesolr/Solr_Base_Query.php).

Right. Fixed.