Move Attribute and AttributeSet to ActiveModel

Use these to back the attributes API.  Stop automatically including
ActiveModel::Dirty in ActiveModel::Attributes, and make it optional.

5 files changed, 532 insertions, 32 deletions

diff --git a/activemodel/test/cases/attribute_set_test.rb b/activemodel/test/cases/attribute_set_test.rb
new file mode 100644
index 0000000000..d50e6cfa7a
--- /dev/null
+++ b/activemodel/test/cases/attribute_set_test.rb
@@ -0,0 +1,255 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+module ActiveModel
+  class AttributeSetTest < ActiveModel::TestCase
+    test "building a new set from raw attributes" do
+      builder = AttributeSet::Builder.new(foo: Type::Integer.new, bar: Type::Float.new)
+      attributes = builder.build_from_database(foo: "1.1", bar: "2.2")
+
+      assert_equal 1, attributes[:foo].value
+      assert_equal 2.2, attributes[:bar].value
+      assert_equal :foo, attributes[:foo].name
+      assert_equal :bar, attributes[:bar].name
+    end
+
+    test "building with custom types" do
+      builder = AttributeSet::Builder.new(foo: Type::Float.new)
+      attributes = builder.build_from_database({ foo: "3.3", bar: "4.4" }, { bar: Type::Integer.new })
+
+      assert_equal 3.3, attributes[:foo].value
+      assert_equal 4, attributes[:bar].value
+    end
+
+    test "[] returns a null object" do
+      builder = AttributeSet::Builder.new(foo: Type::Float.new)
+      attributes = builder.build_from_database(foo: "3.3")
+
+      assert_equal "3.3", attributes[:foo].value_before_type_cast
+      assert_nil attributes[:bar].value_before_type_cast
+      assert_equal :bar, attributes[:bar].name
+    end
+
+    test "duping creates a new hash, but does not dup the attributes" do
+      builder = AttributeSet::Builder.new(foo: Type::Integer.new, bar: Type::String.new)
+      attributes = builder.build_from_database(foo: 1, bar: "foo")
+
+      # Ensure the type cast value is cached
+      attributes[:foo].value
+      attributes[:bar].value
+
+      duped = attributes.dup
+      duped.write_from_database(:foo, 2)
+      duped[:bar].value << "bar"
+
+      assert_equal 1, attributes[:foo].value
+      assert_equal 2, duped[:foo].value
+      assert_equal "foobar", attributes[:bar].value
+      assert_equal "foobar", duped[:bar].value
+    end
+
+    test "deep_duping creates a new hash and dups each attribute" do
+      builder = AttributeSet::Builder.new(foo: Type::Integer.new, bar: Type::String.new)
+      attributes = builder.build_from_database(foo: 1, bar: "foo")
+
+      # Ensure the type cast value is cached
+      attributes[:foo].value
+      attributes[:bar].value
+
+      duped = attributes.deep_dup
+      duped.write_from_database(:foo, 2)
+      duped[:bar].value << "bar"
+
+      assert_equal 1, attributes[:foo].value
+      assert_equal 2, duped[:foo].value
+      assert_equal "foo", attributes[:bar].value
+      assert_equal "foobar", duped[:bar].value
+    end
+
+    test "freezing cloned set does not freeze original" do
+      attributes = AttributeSet.new({})
+      clone = attributes.clone
+
+      clone.freeze
+
+      assert clone.frozen?
+      assert_not attributes.frozen?
+    end
+
+    test "to_hash returns a hash of the type cast values" do
+      builder = AttributeSet::Builder.new(foo: Type::Integer.new, bar: Type::Float.new)
+      attributes = builder.build_from_database(foo: "1.1", bar: "2.2")
+
+      assert_equal({ foo: 1, bar: 2.2 }, attributes.to_hash)
+      assert_equal({ foo: 1, bar: 2.2 }, attributes.to_h)
+    end
+
+    test "to_hash maintains order" do
+      builder = AttributeSet::Builder.new(foo: Type::Integer.new, bar: Type::Float.new)
+      attributes = builder.build_from_database(foo: "2.2", bar: "3.3")
+
+      attributes[:bar]
+      hash = attributes.to_h
+
+      assert_equal [[:foo, 2], [:bar, 3.3]], hash.to_a
+    end
+
+    test "values_before_type_cast" do
+      builder = AttributeSet::Builder.new(foo: Type::Integer.new, bar: Type::Integer.new)
+      attributes = builder.build_from_database(foo: "1.1", bar: "2.2")
+
+      assert_equal({ foo: "1.1", bar: "2.2" }, attributes.values_before_type_cast)
+    end
+
+    test "known columns are built with uninitialized attributes" do
+      attributes = attributes_with_uninitialized_key
+      assert attributes[:foo].initialized?
+      assert_not attributes[:bar].initialized?
+    end
+
+    test "uninitialized attributes are not included in the attributes hash" do
+      attributes = attributes_with_uninitialized_key
+      assert_equal({ foo: 1 }, attributes.to_hash)
+    end
+
+    test "uninitialized attributes are not included in keys" do
+      attributes = attributes_with_uninitialized_key
+      assert_equal [:foo], attributes.keys
+    end
+
+    test "uninitialized attributes return false for key?" do
+      attributes = attributes_with_uninitialized_key
+      assert attributes.key?(:foo)
+      assert_not attributes.key?(:bar)
+    end
+
+    test "unknown attributes return false for key?" do
+      attributes = attributes_with_uninitialized_key
+      assert_not attributes.key?(:wibble)
+    end
+
+    test "fetch_value returns the value for the given initialized attribute" do
+      builder = AttributeSet::Builder.new(foo: Type::Integer.new, bar: Type::Float.new)
+      attributes = builder.build_from_database(foo: "1.1", bar: "2.2")
+
+      assert_equal 1, attributes.fetch_value(:foo)
+      assert_equal 2.2, attributes.fetch_value(:bar)
+    end
+
+    test "fetch_value returns nil for unknown attributes" do
+      attributes = attributes_with_uninitialized_key
+      assert_nil attributes.fetch_value(:wibble) { "hello" }
+    end
+
+    test "fetch_value returns nil for unknown attributes when types has a default" do
+      types = Hash.new(Type::Value.new)
+      builder = AttributeSet::Builder.new(types)
+      attributes = builder.build_from_database
+
+      assert_nil attributes.fetch_value(:wibble) { "hello" }
+    end
+
+    test "fetch_value uses the given block for uninitialized attributes" do
+      attributes = attributes_with_uninitialized_key
+      value = attributes.fetch_value(:bar) { |n| n.to_s + "!" }
+      assert_equal "bar!", value
+    end
+
+    test "fetch_value returns nil for uninitialized attributes if no block is given" do
+      attributes = attributes_with_uninitialized_key
+      assert_nil attributes.fetch_value(:bar)
+    end
+
+    test "the primary_key is always initialized" do
+      builder = AttributeSet::Builder.new({ foo: Type::Integer.new }, :foo)
+      attributes = builder.build_from_database
+
+      assert attributes.key?(:foo)
+      assert_equal [:foo], attributes.keys
+      assert attributes[:foo].initialized?
+    end
+
+    class MyType
+      def cast(value)
+        return if value.nil?
+        value + " from user"
+      end
+
+      def deserialize(value)
+        return if value.nil?
+        value + " from database"
+      end
+
+      def assert_valid_value(*)
+      end
+    end
+
+    test "write_from_database sets the attribute with database typecasting" do
+      builder = AttributeSet::Builder.new(foo: MyType.new)
+      attributes = builder.build_from_database
+
+      assert_nil attributes.fetch_value(:foo)
+
+      attributes.write_from_database(:foo, "value")
+
+      assert_equal "value from database", attributes.fetch_value(:foo)
+    end
+
+    test "write_from_user sets the attribute with user typecasting" do
+      builder = AttributeSet::Builder.new(foo: MyType.new)
+      attributes = builder.build_from_database
+
+      assert_nil attributes.fetch_value(:foo)
+
+      attributes.write_from_user(:foo, "value")
+
+      assert_equal "value from user", attributes.fetch_value(:foo)
+    end
+
+    def attributes_with_uninitialized_key
+      builder = AttributeSet::Builder.new(foo: Type::Integer.new, bar: Type::Float.new)
+      builder.build_from_database(foo: "1.1")
+    end
+
+    test "freezing doesn't prevent the set from materializing" do
+      builder = AttributeSet::Builder.new(foo: Type::String.new)
+      attributes = builder.build_from_database(foo: "1")
+
+      attributes.freeze
+      assert_equal({ foo: "1" }, attributes.to_hash)
+    end
+
+    test "#accessed_attributes returns only attributes which have been read" do
+      builder = AttributeSet::Builder.new(foo: Type::Value.new, bar: Type::Value.new)
+      attributes = builder.build_from_database(foo: "1", bar: "2")
+
+      assert_equal [], attributes.accessed
+
+      attributes.fetch_value(:foo)
+
+      assert_equal [:foo], attributes.accessed
+    end
+
+    test "#map returns a new attribute set with the changes applied" do
+      builder = AttributeSet::Builder.new(foo: Type::Integer.new, bar: Type::Integer.new)
+      attributes = builder.build_from_database(foo: "1", bar: "2")
+      new_attributes = attributes.map do |attr|
+        attr.with_cast_value(attr.value + 1)
+      end
+
+      assert_equal 2, new_attributes.fetch_value(:foo)
+      assert_equal 3, new_attributes.fetch_value(:bar)
+    end
+
+    test "comparison for equality is correctly implemented" do
+      builder = AttributeSet::Builder.new(foo: Type::Integer.new, bar: Type::Integer.new)
+      attributes = builder.build_from_database(foo: "1", bar: "2")
+      attributes2 = builder.build_from_database(foo: "1", bar: "2")
+      attributes3 = builder.build_from_database(foo: "2", bar: "2")
+
+      assert_equal attributes, attributes2
+      assert_not_equal attributes2, attributes3
+    end
+  end
+end
diff --git a/activemodel/test/cases/attribute_test.rb b/activemodel/test/cases/attribute_test.rb
new file mode 100644
index 0000000000..14d86cef97
--- /dev/null
+++ b/activemodel/test/cases/attribute_test.rb
@@ -0,0 +1,255 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+module ActiveModel
+  class AttributeTest < ActiveModel::TestCase
+    setup do
+      @type = Minitest::Mock.new
+    end
+
+    teardown do
+      assert @type.verify
+    end
+
+    test "from_database + read type casts from database" do
+      @type.expect(:deserialize, "type cast from database", ["a value"])
+      attribute = Attribute.from_database(nil, "a value", @type)
+
+      type_cast_value = attribute.value
+
+      assert_equal "type cast from database", type_cast_value
+    end
+
+    test "from_user + read type casts from user" do
+      @type.expect(:cast, "type cast from user", ["a value"])
+      attribute = Attribute.from_user(nil, "a value", @type)
+
+      type_cast_value = attribute.value
+
+      assert_equal "type cast from user", type_cast_value
+    end
+
+    test "reading memoizes the value" do
+      @type.expect(:deserialize, "from the database", ["whatever"])
+      attribute = Attribute.from_database(nil, "whatever", @type)
+
+      type_cast_value = attribute.value
+      second_read = attribute.value
+
+      assert_equal "from the database", type_cast_value
+      assert_same type_cast_value, second_read
+    end
+
+    test "reading memoizes falsy values" do
+      @type.expect(:deserialize, false, ["whatever"])
+      attribute = Attribute.from_database(nil, "whatever", @type)
+
+      attribute.value
+      attribute.value
+    end
+
+    test "read_before_typecast returns the given value" do
+      attribute = Attribute.from_database(nil, "raw value", @type)
+
+      raw_value = attribute.value_before_type_cast
+
+      assert_equal "raw value", raw_value
+    end
+
+    test "from_database + read_for_database type casts to and from database" do
+      @type.expect(:deserialize, "read from database", ["whatever"])
+      @type.expect(:serialize, "ready for database", ["read from database"])
+      attribute = Attribute.from_database(nil, "whatever", @type)
+
+      serialize = attribute.value_for_database
+
+      assert_equal "ready for database", serialize
+    end
+
+    test "from_user + read_for_database type casts from the user to the database" do
+      @type.expect(:cast, "read from user", ["whatever"])
+      @type.expect(:serialize, "ready for database", ["read from user"])
+      attribute = Attribute.from_user(nil, "whatever", @type)
+
+      serialize = attribute.value_for_database
+
+      assert_equal "ready for database", serialize
+    end
+
+    test "duping dups the value" do
+      @type.expect(:deserialize, "type cast".dup, ["a value"])
+      attribute = Attribute.from_database(nil, "a value", @type)
+
+      value_from_orig = attribute.value
+      value_from_clone = attribute.dup.value
+      value_from_orig << " foo"
+
+      assert_equal "type cast foo", value_from_orig
+      assert_equal "type cast", value_from_clone
+    end
+
+    test "duping does not dup the value if it is not dupable" do
+      @type.expect(:deserialize, false, ["a value"])
+      attribute = Attribute.from_database(nil, "a value", @type)
+
+      assert_same attribute.value, attribute.dup.value
+    end
+
+    test "duping does not eagerly type cast if we have not yet type cast" do
+      attribute = Attribute.from_database(nil, "a value", @type)
+      attribute.dup
+    end
+
+    class MyType
+      def cast(value)
+        value + " from user"
+      end
+
+      def deserialize(value)
+        value + " from database"
+      end
+
+      def assert_valid_value(*)
+      end
+    end
+
+    test "with_value_from_user returns a new attribute with the value from the user" do
+      old = Attribute.from_database(nil, "old", MyType.new)
+      new = old.with_value_from_user("new")
+
+      assert_equal "old from database", old.value
+      assert_equal "new from user", new.value
+    end
+
+    test "with_value_from_database returns a new attribute with the value from the database" do
+      old = Attribute.from_user(nil, "old", MyType.new)
+      new = old.with_value_from_database("new")
+
+      assert_equal "old from user", old.value
+      assert_equal "new from database", new.value
+    end
+
+    test "uninitialized attributes yield their name if a block is given to value" do
+      block = proc { |name| name.to_s + "!" }
+      foo = Attribute.uninitialized(:foo, nil)
+      bar = Attribute.uninitialized(:bar, nil)
+
+      assert_equal "foo!", foo.value(&block)
+      assert_equal "bar!", bar.value(&block)
+    end
+
+    test "uninitialized attributes have no value" do
+      assert_nil Attribute.uninitialized(:foo, nil).value
+    end
+
+    test "attributes equal other attributes with the same constructor arguments" do
+      first = Attribute.from_database(:foo, 1, Type::Integer.new)
+      second = Attribute.from_database(:foo, 1, Type::Integer.new)
+      assert_equal first, second
+    end
+
+    test "attributes do not equal attributes with different names" do
+      first = Attribute.from_database(:foo, 1, Type::Integer.new)
+      second = Attribute.from_database(:bar, 1, Type::Integer.new)
+      assert_not_equal first, second
+    end
+
+    test "attributes do not equal attributes with different types" do
+      first = Attribute.from_database(:foo, 1, Type::Integer.new)
+      second = Attribute.from_database(:foo, 1, Type::Float.new)
+      assert_not_equal first, second
+    end
+
+    test "attributes do not equal attributes with different values" do
+      first = Attribute.from_database(:foo, 1, Type::Integer.new)
+      second = Attribute.from_database(:foo, 2, Type::Integer.new)
+      assert_not_equal first, second
+    end
+
+    test "attributes do not equal attributes of other classes" do
+      first = Attribute.from_database(:foo, 1, Type::Integer.new)
+      second = Attribute.from_user(:foo, 1, Type::Integer.new)
+      assert_not_equal first, second
+    end
+
+    test "an attribute has not been read by default" do
+      attribute = Attribute.from_database(:foo, 1, Type::Value.new)
+      assert_not attribute.has_been_read?
+    end
+
+    test "an attribute has been read when its value is calculated" do
+      attribute = Attribute.from_database(:foo, 1, Type::Value.new)
+      attribute.value
+      assert attribute.has_been_read?
+    end
+
+    test "an attribute is not changed if it hasn't been assigned or mutated" do
+      attribute = Attribute.from_database(:foo, 1, Type::Value.new)
+
+      refute attribute.changed?
+    end
+
+    test "an attribute is changed if it's been assigned a new value" do
+      attribute = Attribute.from_database(:foo, 1, Type::Value.new)
+      changed = attribute.with_value_from_user(2)
+
+      assert changed.changed?
+    end
+
+    test "an attribute is not changed if it's assigned the same value" do
+      attribute = Attribute.from_database(:foo, 1, Type::Value.new)
+      unchanged = attribute.with_value_from_user(1)
+
+      refute unchanged.changed?
+    end
+
+    test "an attribute can not be mutated if it has not been read,
+      and skips expensive calculations" do
+      type_which_raises_from_all_methods = Object.new
+      attribute = Attribute.from_database(:foo, "bar", type_which_raises_from_all_methods)
+
+      assert_not attribute.changed_in_place?
+    end
+
+    test "an attribute is changed if it has been mutated" do
+      attribute = Attribute.from_database(:foo, "bar", Type::String.new)
+      attribute.value << "!"
+
+      assert attribute.changed_in_place?
+      assert attribute.changed?
+    end
+
+    test "an attribute can forget its changes" do
+      attribute = Attribute.from_database(:foo, "bar", Type::String.new)
+      changed = attribute.with_value_from_user("foo")
+      forgotten = changed.forgetting_assignment
+
+      assert changed.changed? # sanity check
+      refute forgotten.changed?
+    end
+
+    test "with_value_from_user validates the value" do
+      type = Type::Value.new
+      type.define_singleton_method(:assert_valid_value) do |value|
+        if value == 1
+          raise ArgumentError
+        end
+      end
+
+      attribute = Attribute.from_database(:foo, 1, type)
+      assert_equal 1, attribute.value
+      assert_equal 2, attribute.with_value_from_user(2).value
+      assert_raises ArgumentError do
+        attribute.with_value_from_user(1)
+      end
+    end
+
+    test "with_type preserves mutations" do
+      attribute = Attribute.from_database(:foo, "".dup, Type::Value.new)
+      attribute.value << "1"
+
+      assert_equal 1, attribute.with_type(Type::Integer.new).value
+    end
+  end
+end
diff --git a/activemodel/test/cases/attributes_dirty_test.rb b/activemodel/test/cases/attributes_dirty_test.rb
index 26b0e85db3..83a86371e0 100644
--- a/activemodel/test/cases/attributes_dirty_test.rb
+++ b/activemodel/test/cases/attributes_dirty_test.rb
@@ -1,12 +1,12 @@
 # frozen_string_literal: true
 
 require "cases/helper"
-require "active_model/attributes"
 
 class AttributesDirtyTest < ActiveModel::TestCase
   class DirtyModel
     include ActiveModel::Model
     include ActiveModel::Attributes
+    include ActiveModel::Dirty
     attribute :name, :string
     attribute :color, :string
     attribute :size, :integer
@@ -69,12 +69,10 @@ class AttributesDirtyTest < ActiveModel::TestCase
   end
 
   test "attribute mutation" do
-    @model.instance_variable_set("@name", "Yam".dup)
+    @model.name = "Yam"
+    @model.save
     assert !@model.name_changed?
     @model.name.replace("Hadad")
-    assert !@model.name_changed?
-    @model.name_will_change!
-    @model.name.replace("Baal")
     assert @model.name_changed?
   end
 
@@ -190,4 +188,18 @@ class AttributesDirtyTest < ActiveModel::TestCase
     assert_equal "Dmitry", @model.name
     assert_equal "White", @model.color
   end
+
+  test "changing the attribute reports a change only when the cast value changes" do
+    @model.size = "2.3"
+    @model.save
+    @model.size = "2.1"
+
+    assert_equal false, @model.changed?
+
+    @model.size = "5.1"
+
+    assert_equal true, @model.changed?
+    assert_equal true, @model.size_changed?
+    assert_equal({ "size" => [2, 5] }, @model.changes)
+  end
 end
diff --git a/activemodel/test/cases/attributes_test.rb b/activemodel/test/cases/attributes_test.rb
index 064cba40e3..914aee1ac0 100644
--- a/activemodel/test/cases/attributes_test.rb
+++ b/activemodel/test/cases/attributes_test.rb
@@ -1,7 +1,6 @@
 # frozen_string_literal: true
 
 require "cases/helper"
-require "active_model/attributes"
 
 module ActiveModel
   class AttributesTest < ActiveModel::TestCase
@@ -13,7 +12,7 @@ module ActiveModel
       attribute :string_field, :string
       attribute :decimal_field, :decimal
       attribute :string_with_default, :string, default: "default string"
-      attribute :date_field, :string, default: -> { Date.new(2016, 1, 1) }
+      attribute :date_field, :date, default: -> { Date.new(2016, 1, 1) }
       attribute :boolean_field, :boolean
     end
 
@@ -48,31 +47,6 @@ module ActiveModel
       assert_equal true, data.boolean_field
     end
 
-    test "dirty" do
-      data = ModelForAttributesTest.new(
-        integer_field: "2.3",
-        string_field: "Rails FTW",
-        decimal_field: "12.3",
-        boolean_field: "0"
-      )
-
-      assert_equal false, data.changed?
-
-      data.integer_field = "2.1"
-
-      assert_equal false, data.changed?
-
-      data.string_with_default = "default string"
-
-      assert_equal false, data.changed?
-
-      data.integer_field = "5.1"
-
-      assert_equal true, data.changed?
-      assert_equal true, data.integer_field_changed?
-      assert_equal({ "integer_field" => [2, 5] }, data.changes)
-    end
-
     test "nonexistent attribute" do
       assert_raise ActiveModel::UnknownAttributeError do
         ModelForAttributesTest.new(nonexistent: "nonexistent")
diff --git a/activemodel/test/cases/dirty_test.rb b/activemodel/test/cases/dirty_test.rb
index 2cd9e185e6..dfe041ff50 100644
--- a/activemodel/test/cases/dirty_test.rb
+++ b/activemodel/test/cases/dirty_test.rb
@@ -219,4 +219,8 @@ class DirtyTest < ActiveModel::TestCase
     assert_equal "Dmitry", @model.name
     assert_equal "White", @model.color
   end
+
+  test "model can be dup-ed without Attributes" do
+    assert @model.dup
+  end
 end