revise: ugly hack to circumvent acitve record to explode because _two_ (yes TWO. in numbers: 2) instances of the Tracker class are loaded at the same time.

app/controllers/issues_controller.rb

@@ -312,10 +312,18 @@ private
 
     @issue.project = @project
     # Tracker must be set before custom field values
-    @issue.tracker ||= @project.trackers.find((params[:issue] && params[:issue][:tracker_id]) || params[:tracker_id] || :first)
     if @issue.tracker.nil?
-      render_error l(:error_no_tracker_in_project)
-      return false
+      new_tracker = @project.trackers.find((params[:issue] && params[:issue][:tracker_id]) || params[:tracker_id] || :first)
+      if new_tracker
+        # XXX: ugly hack. Somehow _two_ different Tracker classes are loaded here (sometimes).
+        # If that happens ActiveRecord explodes, as it thinks we dont get a Tracker object (which is not true)
+        new_tracker.is_a?(Tracker) ?
+          @issue.tracker = new_tracker :
+          @issue.tracker = Tracker.find(new_tracker.id)
+      else
+        render_error l(:error_no_tracker_in_project)
+        return false
+      end
     end
     @issue.start_date ||= User.current.today if Setting.issue_startdate_is_adddate?
     if params[:issue].is_a?(Hash)