convert models from references to eager_load or left_outer_joins

includes means the ruby object is wanted -- preload
references / eager_load / left_join means it is in sql.
  If we want the ruby object, then eager_load. If just in there for sql; then left_joins

Kept with left_outer_joins because that is currently supported by rbac
(If they are needed, just look for left_outer_joins in rbac and add it)

Author: kbrock

app/models/classification.rb

@@ -31,6 +31,7 @@ class Classification < ApplicationRecord
   scope :is_category, -> { where(:parent_id => nil) }
   scope :is_entry,    -> { where.not(:parent_id => nil) }
 
+  # TODO: move over to joins(:parent) or preload(:parent) - need something that works well with load()
   scope :with_writable_parents, -> { includes(:parent).where(:parents_classifications => {:read_only => false}) }
 
   DEFAULT_NAMESPACE = "/managed".freeze
@@ -211,13 +212,13 @@ def self.create_category!(options)
   end
 
   def self.categories(region_id = my_region_number, ns = DEFAULT_NAMESPACE)
-    cats = is_category.in_region(region_id).includes(:tag, :children)
+    cats = is_category.in_region(region_id).preload(:tag, :children)
     cats.select { |c| c.ns == ns }
   end
 
   def self.category_names_for_perf_by_tag(region_id = my_region_number, ns = DEFAULT_NAMESPACE)
     in_region(region_id).is_category.where(:perf_by_tag => true)
-      .includes(:tag)
+      .preload(:tag)
       .collect { |c| c.name if c.tag2ns(c.tag.name) == ns }
       .compact
   end
@@ -513,7 +514,7 @@ def self.add_entries_from_hash(cat, entries)
   def validate_uniqueness_on_tag_name
     tag_name = Classification.name2tag(name, parent, ns)
     exist_scope = Classification.default_scoped
-                                .includes(:tag)
+                                .left_outer_joins(:tag)
                                 .where(:tags => {:name => tag_name})
                                 .merge(Tag.in_region(region_id))
     exist_scope = exist_scope.where.not(:id => id) unless new_record?

app/models/mixins/assignment_mixin.rb

@@ -221,8 +221,7 @@ def get_assigned_for_target(target, options = {})
       # look for alert_set running off of tags (not individual tags)
       # TODO: we may need to change taggings-related code to use base_model too
       tlist = Tagging.where("tags.name like '/managed/%'")
-                     .where(:taggable => parents)
-                     .references(:tag).includes(:tag).map do |t|
+                     .where(:taggable => parents).eager_load(:tag).map do |t|
         "#{tag_class(t.taggable_type)}/tag#{t.tag.name}"
       end
 

lib/extensions/ar_taggable.rb

@@ -166,10 +166,7 @@ def tag_remove(list, options = {})
   end
 
   def tagged_with(options = {})
-    tagging = Tagging.arel_table
-    query = Tag.includes(:taggings).references(:taggings)
-    query = query.where(tagging[:taggable_type].eq(self.class.base_class.name))
-    query = query.where(tagging[:taggable_id].eq(id))
+    query = Tag.eager_load(:taggings).where(:taggings => {:taggable_type => self.class.base_class.name, :taggable_id => id})
     ns    = Tag.get_namespace(options)
     query = query.where(Tag.arel_table[:name].matches("#{ns}%")) if ns
     query

spec/lib/extensions/ar_order_spec.rb

@@ -7,13 +7,13 @@
   # the string munging gives us issues.
   it "supports order when distinct is present for has_many virtual column" do
     expect do
-      VmOrTemplate.includes(:disks).references(:disks).order(:last_compliance_status).first
+      VmOrTemplate.eager_load(:disks).order(:last_compliance_status).first
     end.not_to raise_error
   end
 
   it "supports order when distinct is present for basic column" do
     expect do
-      VmOrTemplate.includes(:disks).references(:disks).order(:id).first
+      VmOrTemplate.eager_load(:disks).order(:id).first
     end.not_to raise_error
   end
 end

spec/models/container_group_spec.rb

@@ -53,7 +53,7 @@
     it "preloads the conditions" do
       condition_other
       cr = condition_ready
-      cg = ContainerGroup.includes(:ready_condition_status).references(:ready_condition_status).find_by(:id => container_group.id)
+      cg = ContainerGroup.preload(:ready_condition_status).find_by(:id => container_group.id)
 
       expect { expect(cg.ready_condition).to eq(cr) }.to_not make_database_queries
     end

tools/convert_mapped_tags.rb

@@ -28,9 +28,10 @@
   condition_for_mapped_tags = ProviderTagMapping::TAG_PREFIXES.map { "tags.name LIKE ?" }.join(' OR ')
   tag_values = ProviderTagMapping::TAG_PREFIXES.map { |x| "#{x}%:%" }
 
+  # TODO: do we want eager_load, or left join these
   Classification.where.not(:id => Classification.region_to_range) # only other regions(not current, we expected that current region is global)
                 .is_category
-                .includes(:tag, :children).references(:tag, :children)
+                .eager_load(:tag, :children)
                 .where(condition_for_mapped_tags, *tag_values) # only mapped categories
                 .find_each do |category|
     new_parent_category = Classification.in_my_region.find_by(:description => category.description)