users: remove 'hide deleted posts' account setting.

This setting automatically added the `-status:deleted` metatag to all searches. This meant deleted
posts were filtered out at the database level, rather than at the html level. This way searches
wouldn't have less-than-full pages.

The cost was that searches were slower, mainly because post counts weren't cached. Normally when you
search for a tag, we can get the post count from the tags table. If the search is actually like
`touhou -status:deleted`, then we don't know the count and we have to calculate it on demand.

This option is being removed because it did the opposite of what people thought it did. People
thought it made deleted posts visible, when actually it made them more hidden.

app/logical/post_query.rb

@@ -16,11 +16,10 @@ class PostQuery
   SINGLETON_METATAGS = ORDER_METATAGS + %w[limit random]
 
   attr_reader :current_user
-  private attr_reader :tag_limit, :safe_mode, :hide_deleted_posts, :builder
+  private attr_reader :tag_limit, :safe_mode, :builder
 
   delegate :tag?, :metatag?, :wildcard?, :metatags, :wildcards, :tag_names, :to_infix, :to_pretty_string, to: :ast
   alias_method :safe_mode?, :safe_mode
-  alias_method :hide_deleted_posts?, :hide_deleted_posts
   alias_method :to_s, :to_infix
 
   # Return a new PostQuery with aliases replaced.
@@ -42,7 +41,7 @@ class PostQuery
     PostQuery.normalize(search, ...).with_implicit_metatags.posts
   end
 
-  def initialize(search_or_ast, current_user: User.anonymous, tag_limit: nil, safe_mode: false, hide_deleted_posts: false)
+  def initialize(search_or_ast, current_user: User.anonymous, tag_limit: nil, safe_mode: false)
     if search_or_ast.is_a?(AST)
       @ast = search_or_ast
     else
@@ -52,16 +51,15 @@ class PostQuery
     @current_user = current_user
     @tag_limit = tag_limit
     @safe_mode = safe_mode
-    @hide_deleted_posts = hide_deleted_posts
   end
 
   # Build a new PostQuery from the given AST and the current settings.
   def build(ast)
-    PostQuery.new(ast, current_user: current_user, tag_limit: tag_limit, safe_mode: safe_mode, hide_deleted_posts: hide_deleted_posts)
+    PostQuery.new(ast, current_user: current_user, tag_limit: tag_limit, safe_mode: safe_mode)
   end
 
   def builder
-    @builder ||= PostQueryBuilder.new(search, current_user, tag_limit: tag_limit, safe_mode: safe_mode, hide_deleted_posts: hide_deleted_posts)
+    @builder ||= PostQueryBuilder.new(search, current_user, tag_limit: tag_limit, safe_mode: safe_mode)
   end
 
   def search
@@ -189,19 +187,17 @@ class PostQuery
     TagAlias.aliases_for(tag_names)
   end
 
-  # Implicit metatags are metatags added by the user's account settings. rating:s is implicit
-  # under safe mode. -status:deleted is implicit when the "hide deleted posts" setting is on.
+  # Implicit metatags are metatags added by the user's account settings. rating:s is implicit under safe mode.
   def implicit_metatags
     metatags = []
     metatags << AST.metatag("rating", "s") if safe_mode?
-    metatags << -AST.metatag("status", "deleted") if hide_deleted?
     metatags
   end
 
   # XXX unify with PostSets::Post#show_deleted?
   def hide_deleted?
     has_status_metatag = select_metatags(:status).any? { |metatag| metatag.value.downcase.in?(%w[deleted active any all unmoderated modqueue appealed]) }
-    hide_deleted_posts? && !has_status_metatag
+    !has_status_metatag
   end
 
   concerning :CountMethods do

app/logical/post_query_builder.rb

@@ -70,22 +70,19 @@ class PostQueryBuilder
     COUNT_METATAG_SYNONYMS.flat_map { |str| [str, "#{str}_asc"] } +
     CATEGORY_COUNT_METATAGS.flat_map { |str| [str, "#{str}_asc"] }
 
-  attr_reader :query_string, :current_user, :tag_limit, :safe_mode, :hide_deleted_posts
+  attr_reader :query_string, :current_user, :tag_limit, :safe_mode
   alias_method :safe_mode?, :safe_mode
-  alias_method :hide_deleted_posts?, :hide_deleted_posts
 
   # Initialize a post query.
   # @param query_string [String] the tag search
   # @param current_user [User] the user performing the search
   # @param tag_limit [Integer] the user's tag limit
   # @param safe_mode [Boolean] whether safe mode is enabled. if true, return only rating:s posts.
-  # @param hide_deleted_posts [Boolean] if true, filter out status:deleted posts.
-  def initialize(query_string, current_user = User.anonymous, tag_limit: nil, safe_mode: false, hide_deleted_posts: false)
+  def initialize(query_string, current_user = User.anonymous, tag_limit: nil, safe_mode: false)
     @query_string = query_string
     @current_user = current_user
     @tag_limit = tag_limit
     @safe_mode = safe_mode
-    @hide_deleted_posts = hide_deleted_posts
   end
 
   def metatag_matches(name, value, relation = Post.all, quoted: false)

app/logical/post_sets/post.rb

@@ -17,8 +17,8 @@ module PostSets
     alias_method :show_votes?, :show_votes
 
     def initialize(tags, page = 1, per_page = nil, user: CurrentUser.user, format: "html", show_votes: false)
-      @query = PostQueryBuilder.new(tags, user, tag_limit: user.tag_query_limit, safe_mode: CurrentUser.safe_mode?, hide_deleted_posts: user.hide_deleted_posts?)
-      @post_query = PostQuery.normalize(tags, current_user: user, tag_limit: user.tag_query_limit, safe_mode: CurrentUser.safe_mode?, hide_deleted_posts: user.hide_deleted_posts?)
+      @query = PostQueryBuilder.new(tags, user, tag_limit: user.tag_query_limit, safe_mode: CurrentUser.safe_mode?)
+      @post_query = PostQuery.normalize(tags, current_user: user, tag_limit: user.tag_query_limit, safe_mode: CurrentUser.safe_mode?)
       @normalized_query = post_query.with_implicit_metatags
       @tag_string = tags
       @page = page

app/logical/user_deletion.rb

@@ -57,7 +57,6 @@ class UserDeletion
     user.last_forum_read_at = nil
     user.favorite_tags = ""
     user.blacklisted_tags = ""
-    user.hide_deleted_posts = false
     user.show_deleted_children = false
     user.time_zone = "Eastern Time (US & Canada)"
     user.save!