Add ActiveModel::Error and NestedError

Add initialize_dup to deep dup.

Move proc eval and flexible message position out to Errors,
because proc eval is needed for Errors#added? and Errors#delete

3 files changed, 93 insertions, 16 deletions

diff --git a/activemodel/lib/active_model/error.rb b/activemodel/lib/active_model/error.rb
new file mode 100644
index 0000000000..214a0b356d
--- /dev/null
+++ b/activemodel/lib/active_model/error.rb
@@ -0,0 +1,60 @@
+# frozen_string_literal: true
+
+module ActiveModel
+  # == Active \Model \Error
+  #
+  # Represents one single error
+  class Error
+    CALLBACKS_OPTIONS = [:if, :unless, :on, :allow_nil, :allow_blank, :strict]
+    MESSAGE_OPTIONS = [:message]
+
+    def initialize(base, attribute, type, **options)
+      @base = base
+      @attribute = attribute
+      @raw_type = type
+      @type = type || :invalid
+      @options = options
+    end
+
+    def initialize_dup(other)
+      @attribute = @attribute.dup
+      @raw_type = @raw_type.dup
+      @type = @type.dup
+      @options = @options.deep_dup
+    end
+
+    attr_reader :base, :attribute, :type, :raw_type, :options
+
+    def message
+      case raw_type
+      when Symbol
+        base.errors.generate_message(attribute, raw_type, options.except(*CALLBACKS_OPTIONS))
+      else
+        raw_type
+      end
+    end
+
+    def detail
+      { error: raw_type }.merge(options.except(*CALLBACKS_OPTIONS + MESSAGE_OPTIONS))
+    end
+
+    def full_message
+      base.errors.full_message(attribute, message)
+    end
+
+    # See if error matches provided +attribute+, +type+ and +options+.
+    def match?(attribute, type = nil, **options)
+      if @attribute != attribute || (type && @type != type)
+        return false
+      end
+
+      options.each do |key, value|
+        if @options[key] != value
+          return false
+        end
+      end
+
+      true
+    end
+  end
+end
diff --git a/activemodel/lib/active_model/errors.rb b/activemodel/lib/active_model/errors.rb
index 3a692a3e64..7eff374ce3 100644
--- a/activemodel/lib/active_model/errors.rb
+++ b/activemodel/lib/active_model/errors.rb
@@ -59,9 +59,6 @@ module ActiveModel
   class Errors
     include Enumerable
 
-    CALLBACKS_OPTIONS = [:if, :unless, :on, :allow_nil, :allow_blank, :strict]
-    MESSAGE_OPTIONS = [:message]
-
     class << self
       attr_accessor :i18n_customize_full_message # :nodoc:
     end
@@ -532,19 +529,6 @@ module ActiveModel
     end
 
   private
-    def normalize_message(attribute, message, options)
-      case message
-      when Symbol
-        generate_message(attribute, message, options.except(*CALLBACKS_OPTIONS))
-      else
-        message
-      end
-    end
-
-    def normalize_detail(message, options)
-      { error: message }.merge(options.except(*CALLBACKS_OPTIONS + MESSAGE_OPTIONS))
-    end
-
     def without_default_proc(hash)
       hash.dup.tap do |new_h|
         new_h.default_proc = nil
diff --git a/activemodel/lib/active_model/nested_error.rb b/activemodel/lib/active_model/nested_error.rb
new file mode 100644
index 0000000000..b01447ac75
--- /dev/null
+++ b/activemodel/lib/active_model/nested_error.rb
@@ -0,0 +1,33 @@
+# frozen_string_literal: true
+
+require "active_model/error"
+require "forwardable"
+
+module ActiveModel
+  # Represents one single error
+  # @!attribute [r] base
+  #   @return [ActiveModel::Base] the object which the error belongs to
+  # @!attribute [r] attribute
+  #   @return [Symbol] attribute of the object which the error belongs to
+  # @!attribute [r] type
+  #   @return [Symbol] error's type
+  # @!attribute [r] options
+  #   @return [Hash] additional options
+  # @!attribute [r] inner_error
+  #   @return [Error] inner error
+  class NestedError < Error
+    def initialize(base, inner_error, override_options = {})
+      @base = base
+      @inner_error = inner_error
+      @attribute = override_options.fetch(:attribute) { inner_error.attribute }
+      @type = override_options.fetch(:type) { inner_error.type }
+      @raw_type = inner_error.raw_type
+      @options = inner_error.options
+    end
+
+    attr_reader :inner_error
+
+    extend Forwardable
+    def_delegators :@inner_error, :full_message, :message
+  end
+end