Squashed commits since last reviewac-refactor-project-stats

Circumvent rubocop false positive

Ensure tests works on nullable colums

Add documentation

Fix CI failure

switching branches a committed a change from the other MR...

more doc

Use short names

3 files changed, 26 insertions, 15 deletions

diff --git a/app/models/concerns/update_project_statistics.rb b/app/models/concerns/update_project_statistics.rb
index 183eaab241f..bffc711c886 100644
--- a/app/models/concerns/update_project_statistics.rb
+++ b/app/models/concerns/update_project_statistics.rb
@@ -1,25 +1,37 @@
 # frozen_string_literal: true
 
+# This module is providing helpers for updating `ProjectStatistics` with `after_save` and `before_destroy` hooks.
+#
+# It deals with `ProjectStatistics.increment_statistic` making sure not to update statistics on a cascade delete from the
+# project, and keeping track of value deltas on each save. It updates the DB only when a change is needed.
+#
+# How to use
+# - Invoke `update_project_statistics stat: :a_project_statistics_column, attribute: :an_attr_to_track` in a model class body.
+#
+# Expectation
+# - `attribute` must be an ActiveRecord attribute
+# - The model must implement `project` and `project_id`. i.e. direct Project relationship or delegation
 module UpdateProjectStatistics
   extend ActiveSupport::Concern
 
   class_methods do
-    attr_reader :update_project_statistics_attribute,
-                :update_project_statistics_stat
-
-    private
+    attr_reader :statistic_name, :statistic_attribute
 
+    # Configure the model to update +stat+ on ProjectStatistics when +attribute+ changes
+    #
+    # +stat+:: a column of ProjectStatistics to update
+    # +attribute+:: an attribute of the current model, default to +:size+
     def update_project_statistics(stat:, attribute: :size)
-      @update_project_statistics_stat = stat
-      @update_project_statistics_attribute = attribute
+      @statistic_name = stat
+      @statistic_attribute = attribute
 
       after_save(:update_project_statistics_after_save, if: :update_project_statistics_attribute_changed?)
       after_destroy(:update_project_statistics_after_destroy, unless: :project_destroyed?)
     end
+    private :update_project_statistics
   end
 
   included do
-    # rubocop: disable Lint/UselessAccessModifier
     private
 
     def project_destroyed?
@@ -27,22 +39,22 @@ module UpdateProjectStatistics
     end
 
     def update_project_statistics_attribute_changed?
-      attribute_changed?(self.class.update_project_statistics_attribute)
+      attribute_changed?(self.class.statistic_attribute)
     end
 
     def update_project_statistics_after_save
-      attr = self.class.update_project_statistics_attribute
+      attr = self.class.statistic_attribute
       delta = read_attribute(attr).to_i - attribute_was(attr).to_i
 
       update_project_statistics(delta)
     end
 
     def update_project_statistics_after_destroy
-      update_project_statistics(-read_attribute(self.class.update_project_statistics_attribute).to_i)
+      update_project_statistics(-read_attribute(self.class.statistic_attribute).to_i)
     end
 
     def update_project_statistics(delta)
-      ProjectStatistics.increment_statistic(project_id, self.class.update_project_statistics_stat, delta)
+      ProjectStatistics.increment_statistic(project_id, self.class.statistic_name, delta)
     end
   end
 end
diff --git a/lib/api/entities.rb b/lib/api/entities.rb
index 5d4409a445b..4bdac278add 100644
--- a/lib/api/entities.rb
+++ b/lib/api/entities.rb
@@ -304,7 +304,6 @@ module API
       expose :repository_size
       expose :lfs_objects_size
       expose :build_artifacts_size, as: :job_artifacts_size
-      expose :packages_size
     end
 
     class ProjectDailyFetches < Grape::Entity
diff --git a/spec/support/shared_examples/models/update_project_statistics_spec.rb b/spec/support/shared_examples/models/update_project_statistics_spec.rb
index 5a76f221f8e..7a04e940ee5 100644
--- a/spec/support/shared_examples/models/update_project_statistics_spec.rb
+++ b/spec/support/shared_examples/models/update_project_statistics_spec.rb
@@ -4,11 +4,11 @@ require 'spec_helper'
 
 shared_examples_for 'UpdateProjectStatistics' do
   let(:project)   { subject.project }
-  let(:stat)      { described_class.update_project_statistics_stat }
-  let(:attribute) { described_class.update_project_statistics_attribute }
+  let(:stat)      { described_class.statistic_name }
+  let(:attribute) { described_class.statistic_attribute }
 
   def reload_stat
-    project.statistics.reload.send(stat)
+    project.statistics.reload.send(stat).to_i
   end
 
   def read_attribute