From f09fe848da02189a3dafe2d532fefb1379eacac4 Mon Sep 17 00:00:00 2001
From: Yorick Peterse <yorickpeterse@gmail.com>
Date: Thu, 1 Mar 2018 17:16:39 +0100
Subject: [PATCH] Don't use ProjectsFinder in TodosFinder

Using ProjectsFinder in TodosFinder to limit todos to the right projects
leads to overly complicated and slow database queries. This commit
removes the use of ProjectsFinder in favour of using
Project.public_or_visible_to_current_user directly.

Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/43767
---
 app/finders/todos_finder.rb                       | 15 ++++++---------
 .../remove-projects-finder-from-todos-finder.yml  |  5 +++++
 2 files changed, 11 insertions(+), 9 deletions(-)
 create mode 100644 changelogs/unreleased/remove-projects-finder-from-todos-finder.yml

diff --git a/app/finders/todos_finder.rb b/app/finders/todos_finder.rb
index edb17843002..47c8b9b60ed 100644
--- a/app/finders/todos_finder.rb
+++ b/app/finders/todos_finder.rb
@@ -110,10 +110,6 @@ class TodosFinder
     ids
   end
 
-  def projects(items)
-    ProjectsFinder.new(current_user: current_user, project_ids_relation: project_ids(items)).execute
-  end
-
   def type?
     type.present? && %w(Issue MergeRequest).include?(type)
   end
@@ -152,13 +148,14 @@ class TodosFinder
 
   def by_project(items)
     if project?
-      items = items.where(project: project)
+      items.where(project: project)
     else
-      item_projects = projects(items)
-      items = items.merge(item_projects).joins(:project)
-    end
+      projects = Project
+        .public_or_visible_to_user(current_user)
+        .order_id_desc
 
-    items
+      items.joins(:project).merge(projects)
+    end
   end
 
   def by_state(items)
diff --git a/changelogs/unreleased/remove-projects-finder-from-todos-finder.yml b/changelogs/unreleased/remove-projects-finder-from-todos-finder.yml
new file mode 100644
index 00000000000..0a3fc751edb
--- /dev/null
+++ b/changelogs/unreleased/remove-projects-finder-from-todos-finder.yml
@@ -0,0 +1,5 @@
+---
+title: Don't use ProjectsFinder in TodosFinder
+merge_request:
+author:
+type: performance