Refactor AutocompleteControllerdefine-abstraction-levels

This refactors the AutocompleteController according to the guidelines
and boundaries discussed in
https://gitlab.com/gitlab-org/gitlab-ce/issues/49653. Specifically,
ActiveRecord logic is moved to different finders, which are then used in
the controller. View logic in turn is moved to presenters, instead of
directly using ActiveRecord's "to_json" method.

The finder MoveToProjectFinder is also adjusted according to the
abstraction guidelines and boundaries, resulting in a much more simple
finder.

By using finders (and other abstractions) more actively, we can push a
lot of logic out of the controller. We also remove the need for various
"before_action" hooks, though this could be achieved without using
finders as well.

The various finders related to AutcompleteController have also been
moved into a namespace. This removes the need for calling everything
"AutocompleteSmurfFinder", instead you can use
"Autocomplete::SmurfFinder".

1 files changed, 44 insertions, 1 deletions

diff --git a/app/models/user.rb b/app/models/user.rb
index 13b04270a4a..a6ba90794d6 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -19,6 +19,7 @@ class User < ActiveRecord::Base
   include BulkMemberAccessLoad
   include BlocksJsonSerialization
   include WithUploads
+  include OptionallySearch
 
   DEFAULT_NOTIFICATION_LEVEL = :participating
 
@@ -253,11 +254,41 @@ class User < ActiveRecord::Base
   scope :external, -> { where(external: true) }
   scope :active, -> { with_state(:active).non_internal }
   scope :without_projects, -> { joins('LEFT JOIN project_authorizations ON users.id = project_authorizations.user_id').where(project_authorizations: { user_id: nil }) }
-  scope :todo_authors, ->(user_id, state) { where(id: Todo.where(user_id: user_id, state: state).select(:author_id)) }
   scope :order_recent_sign_in, -> { reorder(Gitlab::Database.nulls_last_order('current_sign_in_at', 'DESC')) }
   scope :order_oldest_sign_in, -> { reorder(Gitlab::Database.nulls_last_order('current_sign_in_at', 'ASC')) }
   scope :confirmed, -> { where.not(confirmed_at: nil) }
 
+  # Limits the users to those that have TODOs, optionally in the given state.
+  #
+  # user - The user to get the todos for.
+  #
+  # with_todos - If we should limit the result set to users that are the
+  #              authors of todos.
+  #
+  # todo_state - An optional state to require the todos to be in.
+  def self.limit_to_todo_authors(user: nil, with_todos: false, todo_state: nil)
+    if user && with_todos
+      where(id: Todo.where(user: user, state: todo_state).select(:author_id))
+    else
+      all
+    end
+  end
+
+  # Returns a relation that optionally includes the given user.
+  #
+  # user_id - The ID of the user to include.
+  def self.union_with_user(user_id = nil)
+    if user_id.present?
+      union = Gitlab::SQL::Union.new([all, User.unscoped.where(id: user_id)])
+
+      # We use "unscoped" here so that any inner conditions are not repeated for
+      # the outer query, which would be redundant.
+      User.unscoped.from("(#{union.to_sql}) #{User.table_name}")
+    else
+      all
+    end
+  end
+
   def self.with_two_factor_indistinct
     joins("LEFT OUTER JOIN u2f_registrations AS u2f ON u2f.user_id = users.id")
       .where("u2f.id IS NOT NULL OR users.otp_required_for_login = ?", true)
@@ -365,6 +396,18 @@ class User < ActiveRecord::Base
       ).reorder(order % { query: ActiveRecord::Base.connection.quote(query) }, :name)
     end
 
+    # Limits the result set to users _not_ in the given query/list of IDs.
+    #
+    # users - The list of users to ignore. This can be an
+    #         `ActiveRecord::Relation`, or an Array.
+    def where_not_in(users = nil)
+      users ? where.not(id: users) : all
+    end
+
+    def reorder_by_name
+      reorder(:name)
+    end
+
     # searches user by given pattern
     # it compares name, email, username fields and user's secondary emails with given pattern
     # This method uses ILIKE on PostgreSQL and LIKE on MySQL.