- Patch #45281 by chx: made categories with forum topics work again.

modules/forum.module

@@ -604,7 +604,7 @@ function forum_form(&$node) {
 function forum_prepare(&$node) {
   if (!$node->nid) {
     // new topic
-    $node->taxonomy[] = arg(3);
+    $node->taxonomy[arg(3)] = 1;
   }
 }
 

modules/forum/forum.module

@@ -604,7 +604,7 @@ function forum_form(&$node) {
 function forum_prepare(&$node) {
   if (!$node->nid) {
     // new topic
-    $node->taxonomy[] = arg(3);
+    $node->taxonomy[arg(3)] = 1;
   }
 }
 

modules/taxonomy.module

@@ -531,8 +531,7 @@ function taxonomy_form_alter($form_id, &$form) {
         $form['taxonomy']['tags'][$vocabulary->vid] = array('#type' => 'textfield', '#default_value' => $typed_string, '#maxlength' => 100, '#autocomplete_path' => 'taxonomy/autocomplete/'. $vocabulary->vid, '#required' => $vocabulary->required, '#title' => $vocabulary->name, '#description' => $help);
       }
       else {
-        $ntterms = isset($node->taxonomy) ? $terms : array_keys($terms);
-        $form['taxonomy'][$vocabulary->vid] = taxonomy_form($vocabulary->vid, $ntterms, $help, 'taxonomy');
+        $form['taxonomy'][$vocabulary->vid] = taxonomy_form($vocabulary->vid, array_keys($terms), $help);
         $form['taxonomy'][$vocabulary->vid]['#weight'] = $vocabulary->weight;
       }
     }

modules/taxonomy/taxonomy.module

@@ -531,8 +531,7 @@ function taxonomy_form_alter($form_id, &$form) {
         $form['taxonomy']['tags'][$vocabulary->vid] = array('#type' => 'textfield', '#default_value' => $typed_string, '#maxlength' => 100, '#autocomplete_path' => 'taxonomy/autocomplete/'. $vocabulary->vid, '#required' => $vocabulary->required, '#title' => $vocabulary->name, '#description' => $help);
       }
       else {
-        $ntterms = isset($node->taxonomy) ? $terms : array_keys($terms);
-        $form['taxonomy'][$vocabulary->vid] = taxonomy_form($vocabulary->vid, $ntterms, $help, 'taxonomy');
+        $form['taxonomy'][$vocabulary->vid] = taxonomy_form($vocabulary->vid, array_keys($terms), $help);
         $form['taxonomy'][$vocabulary->vid]['#weight'] = $vocabulary->weight;
       }
     }