Remove dead code and refactor status threading code (#20357)

* Remove dead code

* Remove unneeded/broken parameters and refactor descendant computation

app/controllers/api/v1/statuses_controller.rb

@@ -40,7 +40,7 @@ class Api::V1::StatusesController < Api::BaseController
     end
 
     ancestors_results   = @status.in_reply_to_id.nil? ? [] : @status.ancestors(ancestors_limit, current_account)
-    descendants_results = @status.descendants(descendants_limit, current_account, nil, nil, descendants_depth_limit)
+    descendants_results = @status.descendants(descendants_limit, current_account, descendants_depth_limit)
     loaded_ancestors    = cache_collection(ancestors_results, Status)
     loaded_descendants  = cache_collection(descendants_results, Status)
 

app/controllers/concerns/status_controller_concern.rb

@@ -1,87 +0,0 @@
-# frozen_string_literal: true
-
-module StatusControllerConcern
-  extend ActiveSupport::Concern
-
-  ANCESTORS_LIMIT         = 40
-  DESCENDANTS_LIMIT       = 60
-  DESCENDANTS_DEPTH_LIMIT = 20
-
-  def create_descendant_thread(starting_depth, statuses)
-    depth = starting_depth + statuses.size
-
-    if depth < DESCENDANTS_DEPTH_LIMIT
-      {
-        statuses: statuses,
-        starting_depth: starting_depth,
-      }
-    else
-      next_status = statuses.pop
-
-      {
-        statuses: statuses,
-        starting_depth: starting_depth,
-        next_status: next_status,
-      }
-    end
-  end
-
-  def set_ancestors
-    @ancestors     = @status.reply? ? cache_collection(@status.ancestors(ANCESTORS_LIMIT, current_account), Status) : []
-    @next_ancestor = @ancestors.size < ANCESTORS_LIMIT ? nil : @ancestors.shift
-  end
-
-  def set_descendants
-    @max_descendant_thread_id   = params[:max_descendant_thread_id]&.to_i
-    @since_descendant_thread_id = params[:since_descendant_thread_id]&.to_i
-
-    descendants = cache_collection(
-      @status.descendants(
-        DESCENDANTS_LIMIT,
-        current_account,
-        @max_descendant_thread_id,
-        @since_descendant_thread_id,
-        DESCENDANTS_DEPTH_LIMIT
-      ),
-      Status
-    )
-
-    @descendant_threads = []
-
-    if descendants.present?
-      statuses       = [descendants.first]
-      starting_depth = 0
-
-      descendants.drop(1).each_with_index do |descendant, index|
-        if descendants[index].id == descendant.in_reply_to_id
-          statuses << descendant
-        else
-          @descendant_threads << create_descendant_thread(starting_depth, statuses)
-
-          # The thread is broken, assume it's a reply to the root status
-          starting_depth = 0
-
-          # ... unless we can find its ancestor in one of the already-processed threads
-          @descendant_threads.reverse_each do |descendant_thread|
-            statuses = descendant_thread[:statuses]
-
-            index = statuses.find_index do |thread_status|
-              thread_status.id == descendant.in_reply_to_id
-            end
-
-            if index.present?
-              starting_depth = descendant_thread[:starting_depth] + index + 1
-              break
-            end
-          end
-
-          statuses = [descendant]
-        end
-      end
-
-      @descendant_threads << create_descendant_thread(starting_depth, statuses)
-    end
-
-    @max_descendant_thread_id = @descendant_threads.pop[:statuses].first.id if descendants.size >= DESCENDANTS_LIMIT
-  end
-end

app/controllers/statuses_controller.rb

@@ -2,7 +2,6 @@
 
 class StatusesController < ApplicationController
   include WebAppControllerConcern
-  include StatusControllerConcern
   include SignatureAuthentication
   include Authorization
   include AccountOwnedConcern

app/models/concerns/status_threading_concern.rb

@@ -7,8 +7,8 @@ module StatusThreadingConcern
     find_statuses_from_tree_path(ancestor_ids(limit), account)
   end
 
-  def descendants(limit, account = nil, max_child_id = nil, since_child_id = nil, depth = nil)
+  def descendants(limit, account = nil, depth = nil)
-    find_statuses_from_tree_path(descendant_ids(limit, max_child_id, since_child_id, depth), account, promote: true)
+    find_statuses_from_tree_path(descendant_ids(limit, depth), account, promote: true)
   end
 
   def self_replies(limit)
@@ -50,22 +50,17 @@ module StatusThreadingConcern
     SQL
   end
 
-  def descendant_ids(limit, max_child_id, since_child_id, depth)
+  def descendant_ids(limit, depth)
-    descendant_statuses(limit, max_child_id, since_child_id, depth).pluck(:id)
-  end
-
-  def descendant_statuses(limit, max_child_id, since_child_id, depth)
     # use limit + 1 and depth + 1 because 'self' is included
     depth += 1 if depth.present?
     limit += 1 if limit.present?
 
-    descendants_with_self = Status.find_by_sql([<<-SQL.squish, id: id, limit: limit, max_child_id: max_child_id, since_child_id: since_child_id, depth: depth])
+    descendants_with_self = Status.find_by_sql([<<-SQL.squish, id: id, limit: limit, depth: depth])
-      WITH RECURSIVE search_tree(id, path)
+      WITH RECURSIVE search_tree(id, path) AS (
-      AS (
         SELECT id, ARRAY[id]
         FROM statuses
-        WHERE id = :id AND COALESCE(id < :max_child_id, TRUE) AND COALESCE(id > :since_child_id, TRUE)
+        WHERE id = :id
-        UNION ALL
+      UNION ALL
         SELECT statuses.id, path || statuses.id
         FROM search_tree
         JOIN statuses ON statuses.in_reply_to_id = search_tree.id
@@ -77,7 +72,7 @@ module StatusThreadingConcern
       LIMIT :limit
     SQL
 
-    descendants_with_self - [self]
+    descendants_with_self.pluck(:id) - [id]
   end
 
   def find_statuses_from_tree_path(ids, account, promote: false)