specify virtual_delegate types to avoid deadlock

deriving the attribute type for delegates required the target
class to be loaded.
This forced a cascade of load_schema calls that end up
introducing a race condition.

This PR explicitly declares the attribute type so the target class
no longer needs to be loaded and the race condition
(and subsequent deadlocks) are avoided.

https://bugzilla.redhat.com/show_bug.cgi?id=1700378

Gemfile

@@ -24,7 +24,7 @@ manageiq_plugin "manageiq-providers-ansible_tower" # can't move this down yet, b
 manageiq_plugin "manageiq-schema"
 
 # Unmodified gems
-gem "activerecord-virtual_attributes", "~>1.1.0"
+gem "activerecord-virtual_attributes", "~>1.2.0"
 gem "activerecord-session_store",     "~>1.1"
 gem "acts_as_tree",                   "~>2.7" # acts_as_tree needs to be required so that it loads before ancestry
 gem "ancestry",                       "~>3.0.4",       :require => false

app/models/ems_cluster.rb

@@ -44,7 +44,7 @@ class EmsCluster < ApplicationRecord
   include FilterableMixin
 
   include DriftStateMixin
-  virtual_delegate :last_scan_on, :to => "last_drift_state_timestamp_rec.timestamp", :allow_nil => true
+  virtual_delegate :last_scan_on, :to => "last_drift_state_timestamp_rec.timestamp", :allow_nil => true, :type => :datetime
 
   include RelationshipMixin
   self.default_relationship_type = "ems_metadata"

app/models/entitlement.rb

@@ -7,7 +7,7 @@ class Entitlement < ApplicationRecord
 
   validate :one_kind_of_managed_filter
 
-  virtual_delegate :name, :to => :miq_user_role, :allow_nil => true, :prefix => true
+  virtual_delegate :name, :to => :miq_user_role, :allow_nil => true, :prefix => true, :type => :string
 
   def self.valid_filters?(filters_hash)
     return true  unless filters_hash                  # nil ok

app/models/host.rb

@@ -117,13 +117,13 @@ class Host < ApplicationRecord
 
   virtual_column :os_image_name,                :type => :string,      :uses => [:operating_system, :hardware]
   virtual_column :platform,                     :type => :string,      :uses => [:operating_system, :hardware]
-  virtual_delegate :v_owning_cluster, :to => "ems_cluster.name", :allow_nil => true, :default => ""
+  virtual_delegate :v_owning_cluster, :to => "ems_cluster.name", :allow_nil => true, :default => "", :type => :string
   virtual_column :v_owning_datacenter,          :type => :string,      :uses => :all_relationships
   virtual_column :v_owning_folder,              :type => :string,      :uses => :all_relationships
-  virtual_delegate :cpu_total_cores, :cpu_cores_per_socket, :to => :hardware, :allow_nil => true, :default => 0
-  virtual_delegate :num_cpu,     :to => "hardware.cpu_sockets",        :allow_nil => true, :default => 0
-  virtual_delegate :total_vcpus, :to => "hardware.cpu_total_cores",    :allow_nil => true, :default => 0
-  virtual_delegate :ram_size,    :to => "hardware.memory_mb",          :allow_nil => true, :default => 0
+  virtual_delegate :cpu_total_cores, :cpu_cores_per_socket, :to => :hardware, :allow_nil => true, :default => 0, :type => :integer
+  virtual_delegate :num_cpu,     :to => "hardware.cpu_sockets",        :allow_nil => true, :default => 0, :type => :integer
+  virtual_delegate :total_vcpus, :to => "hardware.cpu_total_cores",    :allow_nil => true, :default => 0, :type => :integer
+  virtual_delegate :ram_size,    :to => "hardware.memory_mb",          :allow_nil => true, :default => 0, :type => :integer
   virtual_column :enabled_inbound_ports,        :type => :numeric_set  # The following are not set to use anything
   virtual_column :enabled_outbound_ports,       :type => :numeric_set  # because get_ports ends up re-querying the
   virtual_column :enabled_udp_inbound_ports,    :type => :numeric_set  # database anyway.
@@ -139,7 +139,7 @@ class Host < ApplicationRecord
   virtual_column :enabled_run_level_4_services, :type => :string_set,  :uses => :host_services
   virtual_column :enabled_run_level_5_services, :type => :string_set,  :uses => :host_services
   virtual_column :enabled_run_level_6_services, :type => :string_set,  :uses => :host_services
-  virtual_delegate :annotation, :to => :hardware, :prefix => "v", :allow_nil => true
+  virtual_delegate :annotation, :to => :hardware, :prefix => "v", :allow_nil => true, :type => :string
   virtual_column :vmm_vendor_display,           :type => :string
   virtual_column :ipmi_enabled,                 :type => :boolean
   virtual_column :archived, :type => :boolean
@@ -163,7 +163,7 @@ class Host < ApplicationRecord
   self.default_relationship_type = "ems_metadata"
 
   include DriftStateMixin
-  virtual_delegate :last_scan_on, :to => "last_drift_state_timestamp_rec.timestamp", :allow_nil => true
+  virtual_delegate :last_scan_on, :to => "last_drift_state_timestamp_rec.timestamp", :allow_nil => true, :type => :datetime
 
   include UuidMixin
   include MiqPolicyMixin

app/models/miq_group.rb

@@ -16,7 +16,7 @@ class MiqGroup < ApplicationRecord
   has_many   :miq_product_features, :through => :miq_user_role
   has_many   :authentications, :dependent => :nullify
 
-  virtual_delegate :miq_user_role_name, :to => :entitlement, :allow_nil => true
+  virtual_delegate :miq_user_role_name, :to => :entitlement, :allow_nil => true, :type => :string
   virtual_column :read_only,          :type => :boolean
   virtual_has_one :sui_product_features, :class_name => "Array"
 

app/models/miq_product_feature.rb

@@ -13,7 +13,7 @@ class MiqProductFeature < ApplicationRecord
   has_many :shares, :through => :miq_product_features_shares
   belongs_to :tenant
 
-  virtual_delegate :identifier, :to => :parent, :prefix => true, :allow_nil => true
+  virtual_delegate :identifier, :to => :parent, :prefix => true, :allow_nil => true, :type => :string
 
   validates_presence_of   :identifier
   validates_uniqueness_of :identifier

app/models/miq_report_result.rb

@@ -12,7 +12,7 @@ class MiqReportResult < ApplicationRecord
 
   serialize :report
 
-  virtual_delegate :description, :to => :miq_group, :prefix => true, :allow_nil => true
+  virtual_delegate :description, :to => :miq_group, :prefix => true, :allow_nil => true, :type => :string
   virtual_attribute :status, :string
   virtual_column :status_message,        :type => :string, :uses => :miq_task
   virtual_has_one :result_set,           :class_name => "Hash"

app/models/miq_server.rb

@@ -37,7 +37,7 @@ class MiqServer < ApplicationRecord
   scope :active_miq_servers, -> { where(:status => STATUSES_ACTIVE) }
   scope :recently_active,    -> { where(:last_heartbeat => 10.minutes.ago.utc...Time.now.utc) }
   scope :with_zone_id, ->(zone_id) { where(:zone_id => zone_id) }
-  virtual_delegate :description, :to => :zone, :prefix => true, :allow_nil => true
+  virtual_delegate :description, :to => :zone, :prefix => true, :allow_nil => true, :type => :string
 
   validate :validate_zone_not_maintenance?
 

app/models/miq_widget.rb

@@ -42,8 +42,8 @@ def destroy_schedule
   end
 
   virtual_column :status,         :type => :string,    :uses => :miq_task
-  virtual_delegate :status_message, :to => "miq_task.message", :allow_nil => true, :default => "Unknown"
-  virtual_delegate :queued_at, :to => "miq_task.created_on", :allow_nil => true
+  virtual_delegate :status_message, :to => "miq_task.message", :allow_nil => true, :default => "Unknown", :type => :string
+  virtual_delegate :queued_at, :to => "miq_task.created_on", :allow_nil => true, :type => :datetime
   virtual_column :last_run_on,    :type => :datetime,  :uses => :miq_schedule
 
   def row_count(row_count_param = nil)

app/models/mixins/authentication_mixin.rb

@@ -13,6 +13,7 @@ module AuthenticationMixin
     virtual_delegate :authentication_status,
                      :to        => "authentication_status_severity_level.status",
                      :default   => "None",
+                     :type      => :string,
                      :allow_nil => true
 
     def self.authentication_check_schedule

app/models/mixins/compliance_mixin.rb

@@ -11,10 +11,12 @@ module ComplianceMixin
 
     virtual_delegate :last_compliance_status,
                      :to        => "last_compliance.compliant",
+                     :type      => :string,
                      :allow_nil => true
     virtual_delegate :timestamp,
                      :to        => :last_compliance,
                      :allow_nil => true,
+                     :type      => :datetime,
                      :prefix    => true
   end
 

app/models/mixins/drift_state_mixin.rb

@@ -9,8 +9,8 @@ module DriftStateMixin
     has_one  :first_drift_state_timestamp_rec, -> { select("id, timestamp, resource_type, resource_id").order("timestamp") }, :as => :resource, :class_name => 'DriftState'
     has_one :last_drift_state_timestamp_rec, -> { order("timestamp DESC").select("id, timestamp, resource_type, resource_id") }, :as => :resource, :class_name => 'DriftState'
 
-    virtual_delegate :first_drift_state_timestamp, :to => "first_drift_state_timestamp_rec.timestamp", :allow_nil => true
-    virtual_delegate :last_drift_state_timestamp, :to => "last_drift_state_timestamp_rec.timestamp", :allow_nil => true
+    virtual_delegate :first_drift_state_timestamp, :to => "first_drift_state_timestamp_rec.timestamp", :allow_nil => true, :type => :datetime
+    virtual_delegate :last_drift_state_timestamp, :to => "last_drift_state_timestamp_rec.timestamp", :allow_nil => true, :type => :datetime
   end
 
   def drift_state_timestamps

app/models/mixins/ownership_mixin.rb

@@ -5,7 +5,7 @@ module OwnershipMixin
     belongs_to :evm_owner, :class_name => "User"
     belongs_to :miq_group
 
-    virtual_delegate :email, :name, :userid, :to => :evm_owner, :prefix => true, :allow_nil => true
+    virtual_delegate :email, :name, :userid, :to => :evm_owner, :prefix => true, :allow_nil => true, :type => :string
 
     # Determine whether the selected object is owned by the current user
     # Resulting SQL:
@@ -25,7 +25,7 @@ module OwnershipMixin
       t.grouping(Arel::Nodes::NamedFunction.new("LOWER", [arel_attribute(:evm_owner_userid)]).eq(userid))
     end)
 
-    virtual_delegate :owning_ldap_group, :to => "miq_group.description", :allow_nil => true
+    virtual_delegate :owning_ldap_group, :to => "miq_group.description", :allow_nil => true, :type => :string
 
     # Determine whether to return objects owned by the current user's miq_group
     # or not.

app/models/vm_or_template.rb

@@ -156,18 +156,18 @@ class VmOrTemplate < ApplicationRecord
   virtual_column :used_storage,                         :type => :integer,    :uses => [:used_disk_storage, :mem_cpu]
   virtual_column :used_storage_by_state,                :type => :integer,    :uses => :used_storage
   virtual_column :uncommitted_storage,                  :type => :integer,    :uses => [:provisioned_storage, :used_storage_by_state]
-  virtual_delegate :ram_size_in_bytes,                  :to => :hardware, :allow_nil => true, :default => 0
-  virtual_delegate :mem_cpu,                            :to => "hardware.memory_mb", :allow_nil => true, :default => 0
-  virtual_delegate :ram_size,                           :to => "hardware.memory_mb", :allow_nil => true, :default => 0
+  virtual_delegate :ram_size_in_bytes,                  :to => :hardware, :allow_nil => true, :default => 0, :type => :integer
+  virtual_delegate :mem_cpu,                            :to => "hardware.memory_mb", :allow_nil => true, :default => 0, :type => :integer
+  virtual_delegate :ram_size,                           :to => "hardware.memory_mb", :allow_nil => true, :default => 0, :type => :integer
   virtual_column :ipaddresses,                          :type => :string_set, :uses => {:hardware => :ipaddresses}
   virtual_column :hostnames,                            :type => :string_set, :uses => {:hardware => :hostnames}
   virtual_column :mac_addresses,                        :type => :string_set, :uses => {:hardware => :mac_addresses}
   virtual_column :memory_exceeds_current_host_headroom, :type => :string,     :uses => [:mem_cpu, {:host => [:hardware, :ext_management_system]}]
   virtual_column :num_hard_disks,                       :type => :integer,    :uses => {:hardware => :hard_disks}
   virtual_column :num_disks,                            :type => :integer,    :uses => {:hardware => :disks}
   virtual_column :num_cpu,                              :type => :integer,    :uses => :hardware
-  virtual_delegate :cpu_total_cores, :cpu_cores_per_socket, :to => :hardware, :allow_nil => true, :default => 0
-  virtual_delegate :annotation, :to => :hardware, :prefix => "v", :allow_nil => true
+  virtual_delegate :cpu_total_cores, :cpu_cores_per_socket, :to => :hardware, :allow_nil => true, :default => 0, :type => :integer
+  virtual_delegate :annotation, :to => :hardware, :prefix => "v", :allow_nil => true, :type => :string
   virtual_column :has_rdm_disk,                         :type => :boolean,    :uses => {:hardware => :disks}
   virtual_column :disks_aligned,                        :type => :string,     :uses => {:hardware => {:hard_disks => :partitions_aligned}}
 
@@ -183,11 +183,11 @@ class VmOrTemplate < ApplicationRecord
   virtual_has_one   :service,              :class_name => 'Service'
   virtual_has_one   :parent_resource,      :class_name => "VmOrTemplate"
 
-  virtual_delegate :name, :to => :host, :prefix => true, :allow_nil => true
-  virtual_delegate :name, :to => :storage, :prefix => true, :allow_nil => true
-  virtual_delegate :name, :to => :ems_cluster, :prefix => true, :allow_nil => true
-  virtual_delegate :vmm_product, :to => :host, :prefix => :v_host, :allow_nil => true
-  virtual_delegate :v_pct_free_disk_space, :v_pct_used_disk_space, :to => :hardware, :allow_nil => true
+  virtual_delegate :name, :to => :host, :prefix => true, :allow_nil => true, :type => :string
+  virtual_delegate :name, :to => :storage, :prefix => true, :allow_nil => true, :type => :string
+  virtual_delegate :name, :to => :ems_cluster, :prefix => true, :allow_nil => true, :type => :string
+  virtual_delegate :vmm_product, :to => :host, :prefix => :v_host, :allow_nil => true, :type => :string
+  virtual_delegate :v_pct_free_disk_space, :v_pct_used_disk_space, :to => :hardware, :allow_nil => true, :type => :float
   delegate :connect_lans, :disconnect_lans, :to => :hardware, :allow_nil => true
 
   before_validation :set_tenant_from_group
@@ -1519,9 +1519,9 @@ def changed_vm_value?(options)
   #
 
   virtual_delegate :allocated_disk_storage, :used_disk_storage,
-                   :to => :hardware, :allow_nil => true, :uses => {:hardware => :disks}
+                   :to => :hardware, :allow_nil => true, :uses => {:hardware => :disks}, :type => :integer
 
-  virtual_delegate :provisioned_storage, :to => :hardware, :allow_nil => true, :default => 0
+  virtual_delegate :provisioned_storage, :to => :hardware, :allow_nil => true, :default => 0, :type => :integer
 
   def used_storage
     used_disk_storage.to_i + ram_size_in_bytes