work around stale object error not being thrown

modules/meeting/app/controllers/meeting_contents_controller.rb

@@ -61,18 +61,17 @@ class MeetingContentsController < ApplicationController
 
   def update
     (render_403; return) unless @content.editable? # TODO: not tested!
-    @content.attributes = content_params
-    @content.author = User.current
+    @content.attributes = content_params.merge(author: User.current)
     @content.attach_files(permitted_params.attachments.to_h)
+
+    if !@content.lock_version_changed?
       if @content.save
         flash[:notice] = I18n.t(:notice_successful_update)
         redirect_back_or_default controller: '/meetings', action: 'show', id: @meeting
       end
-  rescue ActiveRecord::StaleObjectError
-    # Optimistic locking exception
-    flash.now[:error] = I18n.t(:notice_locking_conflict)
-    params[:tab] ||= 'minutes' if @meeting.agenda.present? && @meeting.agenda.locked?
-    render 'meetings/show'
+    else
+      render_conflict
+    end
   end
 
   def history
@@ -137,6 +136,12 @@ class MeetingContentsController < ApplicationController
     render_404
   end
 
+  def render_conflict
+    flash.now[:error] = I18n.t(:notice_locking_conflict)
+    params[:tab] ||= 'minutes' if @meeting.agenda.present? && @meeting.agenda.locked?
+    render 'meetings/show'
+  end
+
   def content_params
     params.require(@content_type).permit(:text, :lock_version, :comment)
   end