From f0ddf87e4bfcfcb861b0a9dca32edb733668bd30 Mon Sep 17 00:00:00 2001 From: Sean Griffin Date: Mon, 25 Jul 2016 11:06:04 -0400 Subject: [PATCH] Correct the behavior of virtual attributes on models loaded from the db Previously we had primarily tested the behavior of these attributes by calling `.new`, allowing this to slip through the cracks. There were a few ways in which they were behaving incorrectly. The biggest issue was that attempting to read the attribute would through a `MissingAttribute` error. We've corrected this by returning the default value when the attribute isn't backed by a database column. This is super special cased, but I don't see a way to avoid this conditional. I had considered handling this higher up in `define_default_attribute`, but we don't have the relevant information there as users can provide new defaults for database columns as well. Once I corrected this, I had noticed that the attributes were always being marked as changed. This is because the behavior of `define_default_attribute` was treating them as assigned from `Attribute::Null`. Finally, with our new implementation, `LazyAttributeHash` could no longer be marshalled, as it holds onto a proc. This has been corrected as well. I've not handled YAML in that class, as we do additional work higher up to avoid YAML dumping it at all. Fixes #25787 Close #25841 --- activerecord/lib/active_record/attribute.rb | 4 +- .../lib/active_record/attribute_set.rb | 2 +- .../active_record/attribute_set/builder.rb | 28 +++++++++--- activerecord/lib/active_record/attributes.rb | 2 +- .../lib/active_record/model_schema.rb | 6 ++- activerecord/test/cases/attributes_test.rb | 44 +++++++++++++++++++ 6 files changed, 74 insertions(+), 12 deletions(-) diff --git a/activerecord/lib/active_record/attribute.rb b/activerecord/lib/active_record/attribute.rb index 9530f134d0..2f41e9e45b 100644 --- a/activerecord/lib/active_record/attribute.rb +++ b/activerecord/lib/active_record/attribute.rb @@ -152,7 +152,7 @@ module ActiveRecord end def _original_value_for_database - value_for_database + type.serialize(original_value) end class FromDatabase < Attribute # :nodoc: @@ -180,7 +180,7 @@ module ActiveRecord value end - def changed_in_place_from?(old_value) + def changed_in_place? false end end diff --git a/activerecord/lib/active_record/attribute_set.rb b/activerecord/lib/active_record/attribute_set.rb index 720d5f8b7c..f868f23845 100644 --- a/activerecord/lib/active_record/attribute_set.rb +++ b/activerecord/lib/active_record/attribute_set.rb @@ -3,7 +3,7 @@ require 'active_record/attribute_set/yaml_encoder' module ActiveRecord class AttributeSet # :nodoc: - delegate :each_value, to: :attributes + delegate :each_value, :fetch, to: :attributes def initialize(attributes) @attributes = attributes diff --git a/activerecord/lib/active_record/attribute_set/builder.rb b/activerecord/lib/active_record/attribute_set/builder.rb index 24a255efc1..4ffd39d82d 100644 --- a/activerecord/lib/active_record/attribute_set/builder.rb +++ b/activerecord/lib/active_record/attribute_set/builder.rb @@ -3,11 +3,12 @@ require 'active_record/attribute' module ActiveRecord class AttributeSet # :nodoc: class Builder # :nodoc: - attr_reader :types, :always_initialized + attr_reader :types, :always_initialized, :default - def initialize(types, always_initialized = nil) + def initialize(types, always_initialized = nil, &default) @types = types @always_initialized = always_initialized + @default = default end def build_from_database(values = {}, additional_types = {}) @@ -15,21 +16,22 @@ module ActiveRecord values[always_initialized] = nil end - attributes = LazyAttributeHash.new(types, values, additional_types) + attributes = LazyAttributeHash.new(types, values, additional_types, &default) AttributeSet.new(attributes) end end end class LazyAttributeHash # :nodoc: - delegate :transform_values, :each_key, :each_value, to: :materialize + delegate :transform_values, :each_key, :each_value, :fetch, to: :materialize - def initialize(types, values, additional_types) + def initialize(types, values, additional_types, &default) @types = types @values = values @additional_types = additional_types @materialized = false @delegate_hash = {} + @default = default || proc {} end def key?(key) @@ -76,9 +78,21 @@ module ActiveRecord end end + def marshal_dump + materialize + end + + def marshal_load(delegate_hash) + @delegate_hash = delegate_hash + @types = {} + @values = {} + @additional_types = {} + @materialized = true + end + protected - attr_reader :types, :values, :additional_types, :delegate_hash + attr_reader :types, :values, :additional_types, :delegate_hash, :default def materialize unless @materialized @@ -101,7 +115,7 @@ module ActiveRecord if value_present delegate_hash[name] = Attribute.from_database(name, value, type) elsif types.key?(name) - delegate_hash[name] = Attribute.uninitialized(name, type) + delegate_hash[name] = default.call(name) || Attribute.uninitialized(name, type) end end end diff --git a/activerecord/lib/active_record/attributes.rb b/activerecord/lib/active_record/attributes.rb index 3211b6eaeb..ed0302e763 100644 --- a/activerecord/lib/active_record/attributes.rb +++ b/activerecord/lib/active_record/attributes.rb @@ -253,7 +253,7 @@ module ActiveRecord name, value, type, - _default_attributes[name], + _default_attributes.fetch(name.to_s) { nil }, ) else default_attribute = Attribute.from_database(name, value, type) diff --git a/activerecord/lib/active_record/model_schema.rb b/activerecord/lib/active_record/model_schema.rb index 99facb4b25..41cebb0e34 100644 --- a/activerecord/lib/active_record/model_schema.rb +++ b/activerecord/lib/active_record/model_schema.rb @@ -249,7 +249,11 @@ module ActiveRecord end def attributes_builder # :nodoc: - @attributes_builder ||= AttributeSet::Builder.new(attribute_types, primary_key) + @attributes_builder ||= AttributeSet::Builder.new(attribute_types, primary_key) do |name| + unless columns_hash.key?(name) + _default_attributes[name].dup + end + end end def columns_hash # :nodoc: diff --git a/activerecord/test/cases/attributes_test.rb b/activerecord/test/cases/attributes_test.rb index 7bcaa53aa2..604411da97 100644 --- a/activerecord/test/cases/attributes_test.rb +++ b/activerecord/test/cases/attributes_test.rb @@ -205,5 +205,49 @@ module ActiveRecord assert_equal(:bar, child.new(foo: :bar).foo) end + + test "attributes not backed by database columns are not dirty when unchanged" do + refute OverloadedType.new.non_existent_decimal_changed? + end + + test "attributes not backed by database columns are always initialized" do + OverloadedType.create! + model = OverloadedType.first + + assert_nil model.non_existent_decimal + model.non_existent_decimal = "123" + assert_equal 123, model.non_existent_decimal + end + + test "attributes not backed by database columns return the default on models loaded from database" do + child = Class.new(OverloadedType) do + attribute :non_existent_decimal, :decimal, default: 123 + end + child.create! + model = child.first + + assert_equal 123, model.non_existent_decimal + end + + test "attributes not backed by database columns properly interact with mutation and dirty" do + child = Class.new(ActiveRecord::Base) do + self.table_name = "topics" + attribute :foo, :string, default: "lol" + end + child.create! + model = child.first + + assert_equal "lol", model.foo + + model.foo << "asdf" + assert_equal "lolasdf", model.foo + assert model.foo_changed? + + model.reload + assert_equal "lol", model.foo + + model.foo = "lol" + refute model.changed? + end end end