Make all belongs_to associations optional

core/app/models/concerns/spree/user_address_book.rb

@@ -25,7 +25,7 @@ def mark_default(user_address)
       has_many :addresses, through: :user_addresses
 
       # bill_address is only minimally used now, but we can't get rid of it without a major version release
-      belongs_to :bill_address, class_name: 'Spree::Address'
+      belongs_to :bill_address, class_name: 'Spree::Address', optional: true
 
       has_one :default_user_address, ->{ default }, class_name: 'Spree::UserAddress', foreign_key: 'user_id'
       has_one :default_address, through: :default_user_address, source: :address

core/app/models/spree/address.rb

@@ -8,8 +8,8 @@ module Spree
   class Address < Spree::Base
     extend ActiveModel::ForbiddenAttributesProtection
 
-    belongs_to :country, class_name: "Spree::Country"
-    belongs_to :state, class_name: "Spree::State"
+    belongs_to :country, class_name: "Spree::Country", optional: true
+    belongs_to :state, class_name: "Spree::State", optional: true
 
     validates :firstname, :address1, :city, :country_id, presence: true
     validates :zipcode, presence: true, if: :require_zipcode?

core/app/models/spree/adjustment.rb

@@ -16,11 +16,11 @@ module Spree
   #    order's adjustment total. This allows an adjustment to be preserved if
   #    it becomes ineligible so it might be reinstated.
   class Adjustment < Spree::Base
-    belongs_to :adjustable, polymorphic: true, touch: true
-    belongs_to :source, polymorphic: true
-    belongs_to :order, class_name: 'Spree::Order', inverse_of: :all_adjustments
-    belongs_to :promotion_code, class_name: 'Spree::PromotionCode'
-    belongs_to :adjustment_reason, class_name: 'Spree::AdjustmentReason', inverse_of: :adjustments
+    belongs_to :adjustable, polymorphic: true, touch: true, optional: true
+    belongs_to :source, polymorphic: true, optional: true
+    belongs_to :order, class_name: 'Spree::Order', inverse_of: :all_adjustments, optional: true
+    belongs_to :promotion_code, class_name: 'Spree::PromotionCode', optional: true
+    belongs_to :adjustment_reason, class_name: 'Spree::AdjustmentReason', inverse_of: :adjustments, optional: true
 
     validates :adjustable, presence: true
     validates :order, presence: true

core/app/models/spree/asset.rb

@@ -2,7 +2,7 @@
 
 module Spree
   class Asset < Spree::Base
-    belongs_to :viewable, polymorphic: true, touch: true
+    belongs_to :viewable, polymorphic: true, touch: true, optional: true
     acts_as_list scope: [:viewable_id, :viewable_type]
   end
 end

core/app/models/spree/base.rb

@@ -6,8 +6,6 @@ class Spree::Base < ActiveRecord::Base
 
   include Spree::RansackableAttributes
 
-  self.belongs_to_required_by_default = false
-
   def initialize_preference_defaults
     if has_attribute?(:preferences)
       self.preferences = default_preferences.merge(preferences)

core/app/models/spree/calculator.rb

@@ -2,7 +2,7 @@
 
 module Spree
   class Calculator < Spree::Base
-    belongs_to :calculable, polymorphic: true
+    belongs_to :calculable, polymorphic: true, optional: true
 
     # This method calls a compute_<computable> method. must be overriden in concrete calculator.
     #

core/app/models/spree/carton.rb

@@ -1,9 +1,9 @@
 # frozen_string_literal: true
 
 class Spree::Carton < Spree::Base
-  belongs_to :address, class_name: 'Spree::Address'
-  belongs_to :stock_location, class_name: 'Spree::StockLocation', inverse_of: :cartons
-  belongs_to :shipping_method, class_name: 'Spree::ShippingMethod', inverse_of: :cartons
+  belongs_to :address, class_name: 'Spree::Address', optional: true
+  belongs_to :stock_location, class_name: 'Spree::StockLocation', inverse_of: :cartons, optional: true
+  belongs_to :shipping_method, class_name: 'Spree::ShippingMethod', inverse_of: :cartons, optional: true
 
   has_many :inventory_units, class_name: "Spree::InventoryUnit", inverse_of: :carton, dependent: :nullify
   has_many :orders, -> { distinct }, through: :inventory_units

core/app/models/spree/classification.rb

@@ -4,8 +4,8 @@ module Spree
   class Classification < Spree::Base
     self.table_name = 'spree_products_taxons'
     acts_as_list scope: :taxon
-    belongs_to :product, class_name: "Spree::Product", inverse_of: :classifications, touch: true
-    belongs_to :taxon, class_name: "Spree::Taxon", inverse_of: :classifications, touch: true
+    belongs_to :product, class_name: "Spree::Product", inverse_of: :classifications, touch: true, optional: true
+    belongs_to :taxon, class_name: "Spree::Taxon", inverse_of: :classifications, touch: true, optional: true
 
     # For https://github.com/spree/spree/issues/3494
     validates_uniqueness_of :taxon_id, scope: :product_id, message: :already_linked

core/app/models/spree/credit_card.rb

@@ -4,8 +4,8 @@ module Spree
   # The default `source` of a `Spree::Payment`.
   #
   class CreditCard < Spree::PaymentSource
-    belongs_to :user, class_name: Spree::UserClassHandle.new, foreign_key: 'user_id'
-    belongs_to :address
+    belongs_to :user, class_name: Spree::UserClassHandle.new, foreign_key: 'user_id', optional: true
+    belongs_to :address, optional: true
 
     before_save :set_last_digits
 

core/app/models/spree/customer_return.rb

@@ -2,7 +2,7 @@
 
 module Spree
   class CustomerReturn < Spree::Base
-    belongs_to :stock_location
+    belongs_to :stock_location, optional: true
 
     has_many :return_items, inverse_of: :customer_return
     has_many :return_authorizations, through: :return_items

core/app/models/spree/inventory_unit.rb

@@ -8,10 +8,10 @@ class InventoryUnit < Spree::Base
     POST_SHIPMENT_STATES = %w(returned)
     CANCELABLE_STATES = ['on_hand', 'backordered', 'shipped']
 
-    belongs_to :variant, -> { with_deleted }, class_name: "Spree::Variant", inverse_of: :inventory_units
-    belongs_to :shipment, class_name: "Spree::Shipment", touch: true, inverse_of: :inventory_units
-    belongs_to :carton, class_name: "Spree::Carton", inverse_of: :inventory_units
-    belongs_to :line_item, class_name: "Spree::LineItem", inverse_of: :inventory_units
+    belongs_to :variant, -> { with_deleted }, class_name: "Spree::Variant", inverse_of: :inventory_units, optional: true
+    belongs_to :shipment, class_name: "Spree::Shipment", touch: true, inverse_of: :inventory_units, optional: true
+    belongs_to :carton, class_name: "Spree::Carton", inverse_of: :inventory_units, optional: true
+    belongs_to :line_item, class_name: "Spree::LineItem", inverse_of: :inventory_units, optional: true
 
     has_many :return_items, inverse_of: :inventory_unit, dependent: :destroy
     has_one :original_return_item, class_name: "Spree::ReturnItem", foreign_key: :exchange_inventory_unit_id, dependent: :destroy

core/app/models/spree/line_item.rb

@@ -12,9 +12,9 @@ module Spree
   class LineItem < Spree::Base
     class CurrencyMismatch < StandardError; end
 
-    belongs_to :order, class_name: "Spree::Order", inverse_of: :line_items, touch: true
-    belongs_to :variant, -> { with_deleted }, class_name: "Spree::Variant", inverse_of: :line_items
-    belongs_to :tax_category, class_name: "Spree::TaxCategory"
+    belongs_to :order, class_name: "Spree::Order", inverse_of: :line_items, touch: true, optional: true
+    belongs_to :variant, -> { with_deleted }, class_name: "Spree::Variant", inverse_of: :line_items, optional: true
+    belongs_to :tax_category, class_name: "Spree::TaxCategory", optional: true
 
     has_one :product, through: :variant
 

core/app/models/spree/line_item_action.rb

@@ -2,7 +2,7 @@
 
 module Spree
   class LineItemAction < Spree::Base
-    belongs_to :line_item
-    belongs_to :action, class_name: "Spree::PromotionAction"
+    belongs_to :line_item, optional: true
+    belongs_to :action, class_name: "Spree::PromotionAction", optional: true
   end
 end

core/app/models/spree/log_entry.rb

@@ -2,7 +2,7 @@
 
 module Spree
   class LogEntry < Spree::Base
-    belongs_to :source, polymorphic: true
+    belongs_to :source, polymorphic: true, optional: true
 
     def parsed_details
       @details ||= YAML.load(details)

core/app/models/spree/option_value.rb

@@ -2,7 +2,7 @@
 
 module Spree
   class OptionValue < Spree::Base
-    belongs_to :option_type, class_name: 'Spree::OptionType', inverse_of: :option_values
+    belongs_to :option_type, class_name: 'Spree::OptionType', inverse_of: :option_values, optional: true
     acts_as_list scope: :option_type
 
     has_many :option_values_variants, dependent: :destroy

core/app/models/spree/option_values_variant.rb

@@ -2,7 +2,7 @@
 
 module Spree
   class OptionValuesVariant < Spree::Base
-    belongs_to :variant
-    belongs_to :option_value
+    belongs_to :variant, optional: true
+    belongs_to :option_value, optional: true
   end
 end

core/app/models/spree/order.rb

@@ -55,15 +55,15 @@ class CannotRebuildShipments < StandardError; end
     deprecate :temporary_credit_card= => :temporary_payment_source=, deprecator: Spree::Deprecation
 
     # Customer info
-    belongs_to :user, class_name: Spree::UserClassHandle.new
-    belongs_to :bill_address, foreign_key: :bill_address_id, class_name: 'Spree::Address'
+    belongs_to :user, class_name: Spree::UserClassHandle.new, optional: true
+    belongs_to :bill_address, foreign_key: :bill_address_id, class_name: 'Spree::Address', optional: true
     alias_attribute :billing_address, :bill_address
 
-    belongs_to :ship_address, foreign_key: :ship_address_id, class_name: 'Spree::Address'
+    belongs_to :ship_address, foreign_key: :ship_address_id, class_name: 'Spree::Address', optional: true
     alias_attribute :shipping_address, :ship_address
     alias_attribute :ship_total, :shipment_total
 
-    belongs_to :store, class_name: 'Spree::Store'
+    belongs_to :store, class_name: 'Spree::Store', optional: true
 
     # Items
     has_many :line_items, -> { order(:created_at, :id) }, dependent: :destroy, inverse_of: :order
@@ -101,9 +101,9 @@ def states
 
     # Logging
     has_many :state_changes, as: :stateful
-    belongs_to :created_by, class_name: Spree::UserClassHandle.new
-    belongs_to :approver, class_name: Spree::UserClassHandle.new
-    belongs_to :canceler, class_name: Spree::UserClassHandle.new
+    belongs_to :created_by, class_name: Spree::UserClassHandle.new, optional: true
+    belongs_to :approver, class_name: Spree::UserClassHandle.new, optional: true
+    belongs_to :canceler, class_name: Spree::UserClassHandle.new, optional: true
 
     accepts_nested_attributes_for :line_items
     accepts_nested_attributes_for :bill_address

core/app/models/spree/order_mutex.rb

@@ -4,7 +4,7 @@ module Spree
   class OrderMutex < Spree::Base
     class LockFailed < StandardError; end
 
-    belongs_to :order, class_name: "Spree::Order"
+    belongs_to :order, class_name: "Spree::Order", optional: true
 
     scope :expired, -> { where(arel_table[:created_at].lteq(Spree::Config[:order_mutex_max_age].seconds.ago)) }
 

core/app/models/spree/order_promotion.rb

@@ -8,9 +8,9 @@ module Spree
   class OrderPromotion < Spree::Base
     self.table_name = 'spree_orders_promotions'
 
-    belongs_to :order, class_name: 'Spree::Order'
-    belongs_to :promotion, class_name: 'Spree::Promotion'
-    belongs_to :promotion_code, class_name: 'Spree::PromotionCode'
+    belongs_to :order, class_name: 'Spree::Order', optional: true
+    belongs_to :promotion, class_name: 'Spree::Promotion', optional: true
+    belongs_to :promotion_code, class_name: 'Spree::PromotionCode', optional: true
 
     validates :order, presence: true
     validates :promotion, presence: true

core/app/models/spree/payment.rb

@@ -15,9 +15,9 @@ class Payment < Spree::Base
     NON_RISKY_AVS_CODES = ['B', 'D', 'H', 'J', 'M', 'Q', 'T', 'V', 'X', 'Y'].freeze
     RISKY_AVS_CODES     = ['A', 'C', 'E', 'F', 'G', 'I', 'K', 'L', 'N', 'O', 'P', 'R', 'S', 'U', 'W', 'Z'].freeze
 
-    belongs_to :order, class_name: 'Spree::Order', touch: true, inverse_of: :payments
-    belongs_to :source, polymorphic: true
-    belongs_to :payment_method, -> { with_deleted }, class_name: 'Spree::PaymentMethod', inverse_of: :payments
+    belongs_to :order, class_name: 'Spree::Order', touch: true, inverse_of: :payments, optional: true
+    belongs_to :source, polymorphic: true, optional: true
+    belongs_to :payment_method, -> { with_deleted }, class_name: 'Spree::PaymentMethod', inverse_of: :payments, optional: true
 
     has_many :offsets, -> { offset_payment }, class_name: "Spree::Payment", foreign_key: :source_id
     has_many :log_entries, as: :source

core/app/models/spree/payment_capture_event.rb

@@ -2,7 +2,7 @@
 
 module Spree
   class PaymentCaptureEvent < Spree::Base
-    belongs_to :payment, class_name: 'Spree::Payment'
+    belongs_to :payment, class_name: 'Spree::Payment', optional: true
 
     def display_amount
       Spree::Money.new(amount, { currency: payment.currency })

core/app/models/spree/payment_source.rb

@@ -4,7 +4,7 @@ module Spree
   class PaymentSource < Spree::Base
     self.abstract_class = true
 
-    belongs_to :payment_method
+    belongs_to :payment_method, optional: true
 
     has_many :payments, as: :source
     has_many :wallet_payment_sources, class_name: 'Spree::WalletPaymentSource', as: :payment_source, inverse_of: :payment_source

core/app/models/spree/price.rb

@@ -12,8 +12,8 @@ class Price < Spree::Base
 
     MAXIMUM_AMOUNT = BigDecimal('99_999_999.99')
 
-    belongs_to :variant, -> { with_deleted }, class_name: 'Spree::Variant', touch: true
-    belongs_to :country, class_name: "Spree::Country", foreign_key: "country_iso", primary_key: "iso"
+    belongs_to :variant, -> { with_deleted }, class_name: 'Spree::Variant', touch: true, optional: true
+    belongs_to :country, class_name: "Spree::Country", foreign_key: "country_iso", primary_key: "iso", optional: true
 
     delegate :product, to: :variant
     delegate :tax_rates, to: :variant

core/app/models/spree/product.rb

@@ -44,8 +44,8 @@ class Product < Spree::Base
     has_many :product_promotion_rules, dependent: :destroy
     has_many :promotion_rules, through: :product_promotion_rules
 
-    belongs_to :tax_category, class_name: 'Spree::TaxCategory'
-    belongs_to :shipping_category, class_name: 'Spree::ShippingCategory', inverse_of: :products
+    belongs_to :tax_category, class_name: 'Spree::TaxCategory', optional: true
+    belongs_to :shipping_category, class_name: 'Spree::ShippingCategory', inverse_of: :products, optional: true
 
     has_one :master,
       -> { where(is_master: true).with_deleted },

core/app/models/spree/product_option_type.rb

@@ -2,8 +2,8 @@
 
 module Spree
   class ProductOptionType < Spree::Base
-    belongs_to :product, class_name: 'Spree::Product', inverse_of: :product_option_types, touch: true
-    belongs_to :option_type, class_name: 'Spree::OptionType', inverse_of: :product_option_types
+    belongs_to :product, class_name: 'Spree::Product', inverse_of: :product_option_types, touch: true, optional: true
+    belongs_to :option_type, class_name: 'Spree::OptionType', inverse_of: :product_option_types, optional: true
     acts_as_list scope: :product
   end
 end

core/app/models/spree/product_promotion_rule.rb

@@ -2,7 +2,7 @@
 
 module Spree
   class ProductPromotionRule < Spree::Base
-    belongs_to :product
-    belongs_to :promotion_rule
+    belongs_to :product, optional: true
+    belongs_to :promotion_rule, optional: true
   end
 end

core/app/models/spree/product_property.rb

@@ -6,8 +6,8 @@ class ProductProperty < Spree::Base
 
     acts_as_list scope: :product
 
-    belongs_to :product, touch: true, class_name: 'Spree::Product', inverse_of: :product_properties
-    belongs_to :property, class_name: 'Spree::Property', inverse_of: :product_properties
+    belongs_to :product, touch: true, class_name: 'Spree::Product', inverse_of: :product_properties, optional: true
+    belongs_to :property, class_name: 'Spree::Property', inverse_of: :product_properties, optional: true
 
     self.whitelisted_ransackable_attributes = ['value']
   end

core/app/models/spree/promotion.rb

@@ -7,7 +7,7 @@ class Promotion < Spree::Base
 
     attr_reader :eligibility_errors
 
-    belongs_to :promotion_category
+    belongs_to :promotion_category, optional: true
 
     has_many :promotion_rules, autosave: true, dependent: :destroy, inverse_of: :promotion
     alias_method :rules, :promotion_rules

core/app/models/spree/promotion_action.rb

@@ -14,7 +14,7 @@ class PromotionAction < Spree::Base
     include Discard::Model
     self.discard_column = :deleted_at
 
-    belongs_to :promotion, class_name: 'Spree::Promotion', inverse_of: :promotion_actions
+    belongs_to :promotion, class_name: 'Spree::Promotion', inverse_of: :promotion_actions, optional: true
 
     scope :of_type, ->(t) { where(type: Array.wrap(t).map(&:to_s)) }
     scope :shipping, -> { of_type(Spree::Config.environment.promotions.shipping_actions.to_a) }

core/app/models/spree/promotion_code.rb

@@ -1,8 +1,8 @@
 # frozen_string_literal: true
 
 class Spree::PromotionCode < Spree::Base
-  belongs_to :promotion, inverse_of: :codes
-  belongs_to :promotion_code_batch, class_name: "Spree::PromotionCodeBatch"
+  belongs_to :promotion, inverse_of: :codes, optional: true
+  belongs_to :promotion_code_batch, class_name: "Spree::PromotionCodeBatch", optional: true
   has_many :adjustments
 
   validates :value, presence: true, uniqueness: { allow_blank: true }

core/app/models/spree/promotion_code_batch.rb

@@ -5,7 +5,7 @@ class PromotionCodeBatch < ActiveRecord::Base
     class CantProcessStartedBatch < StandardError
     end
 
-    belongs_to :promotion, class_name: "Spree::Promotion"
+    belongs_to :promotion, class_name: "Spree::Promotion", optional: true
     has_many :promotion_codes, class_name: "Spree::PromotionCode", dependent: :destroy
 
     validates :number_of_codes, numericality: { greater_than: 0 }

core/app/models/spree/promotion_rule.rb

@@ -3,7 +3,7 @@
 module Spree
   # Base class for all promotion rules
   class PromotionRule < Spree::Base
-    belongs_to :promotion, class_name: 'Spree::Promotion', inverse_of: :promotion_rules
+    belongs_to :promotion, class_name: 'Spree::Promotion', inverse_of: :promotion_rules, optional: true
 
     scope :of_type, ->(t) { where(type: t) }
 

core/app/models/spree/promotion_rule_role.rb

@@ -2,7 +2,7 @@
 
 module Spree
   class PromotionRuleRole < ActiveRecord::Base
-    belongs_to :promotion_rule, class_name: 'Spree::PromotionRule'
-    belongs_to :role, class_name: 'Spree::Role'
+    belongs_to :promotion_rule, class_name: 'Spree::PromotionRule', optional: true
+    belongs_to :role, class_name: 'Spree::Role', optional: true
   end
 end

core/app/models/spree/promotion_rule_store.rb

@@ -4,7 +4,7 @@ module Spree
   class PromotionRuleStore < Spree::Base
     self.table_name = "spree_promotion_rules_stores"
 
-    belongs_to :promotion_rule, class_name: "Spree::PromotionRule"
-    belongs_to :store, class_name: "Spree::Store"
+    belongs_to :promotion_rule, class_name: "Spree::PromotionRule", optional: true
+    belongs_to :store, class_name: "Spree::Store", optional: true
   end
 end

core/app/models/spree/promotion_rule_taxon.rb

@@ -2,7 +2,7 @@
 
 module Spree
   class PromotionRuleTaxon < Spree::Base
-    belongs_to :promotion_rule
-    belongs_to :taxon
+    belongs_to :promotion_rule, optional: true
+    belongs_to :taxon, optional: true
   end
 end