Staff can enter and view deleted topics

lib/guardian.rb

@@ -242,7 +242,11 @@ class Guardian
   end
 
   def can_create_post_on_topic?(topic)
-    is_staff? || (not(topic.closed? || topic.archived?) && can_create_post?(topic))
+
+    # No users can create posts on deleted topics
+    return false if topic.trashed?
+
+    is_staff? || (not(topic.closed? || topic.archived? || topic.trashed?) && can_create_post?(topic))
   end
 
   # Editing Methods
@@ -283,7 +287,9 @@ class Guardian
   end
 
   def can_delete_topic?(topic)
-    is_staff? && not(Category.exists?(topic_id: topic.id))
+    !topic.trashed? &&
+    is_staff? &&
+    !(Category.exists?(topic_id: topic.id))
   end
 
   def can_delete_post_action?(post_action)

lib/topic_view.rb

@@ -8,17 +8,18 @@ class TopicView
   attr_accessor :draft, :draft_key, :draft_sequence
 
   def initialize(topic_id, user=nil, options={})
+    @user = user
     @topic = find_topic(topic_id)
+
     raise Discourse::NotFound if @topic.blank?
 
-    @guardian = Guardian.new(user)
+    @guardian = Guardian.new(@user)
 
     # Special case: If the topic is private and the user isn't logged in, ask them
     # to log in!
-    if @topic.present? && @topic.private_message? && user.blank?
+    if @topic.present? && @topic.private_message? && @user.blank?
       raise Discourse::NotLoggedIn.new
     end
-
     guardian.ensure_can_see!(@topic)
 
     @post_number, @page = options[:post_number], options[:page].to_i
@@ -36,14 +37,13 @@ class TopicView
       @filtered_posts = @filtered_posts.where('post_number = 1 or user_id in (select u.id from users u where username_lower in (?))', usernames)
     end
 
-    @user = user
     @initial_load = true
     @index_reverse = false
 
     filter_posts(options)
 
     @draft_key = @topic.draft_key
-    @draft_sequence = DraftSequence.current(user, @draft_key)
+    @draft_sequence = DraftSequence.current(@user, @draft_key)
   end
 
   def canonical_path
@@ -317,6 +317,8 @@ class TopicView
   end
 
   def find_topic(topic_id)
-    Topic.where(id: topic_id).includes(:category).first
+    finder = Topic.where(id: topic_id).includes(:category)
+    finder = finder.with_deleted if @user.try(:staff?)
+    finder.first
   end
 end

lib/trashable.rb

@@ -5,7 +5,6 @@ module Trashable
     default_scope where(with_deleted_scope_sql)
 
     # scope unscoped does not work
-
     belongs_to :deleted_by, class_name: 'User'
   end
 
@@ -26,6 +25,10 @@ module Trashable
     end
   end
 
+  def trashed?
+    deleted_at.present?
+  end
+
   def trash!(trashed_by=nil)
     # note, an argument could be made that the column should probably called trashed_at
     # however, deleted_at is the terminology used in the UI