Merge pull request #32956 from Shopify/i18n_activemodel_errors_full_message

Allow to override the full_message error format

2 files changed, 52 insertions, 2 deletions

diff --git a/activemodel/lib/active_model/errors.rb b/activemodel/lib/active_model/errors.rb
index 275e3f1313..d583d48b54 100644
--- a/activemodel/lib/active_model/errors.rb
+++ b/activemodel/lib/active_model/errors.rb
@@ -62,6 +62,11 @@ module ActiveModel
     CALLBACKS_OPTIONS = [:if, :unless, :on, :allow_nil, :allow_blank, :strict]
     MESSAGE_OPTIONS = [:message]
 
+    class << self
+      attr_accessor :i18n_full_message # :nodoc:
+    end
+    self.i18n_full_message = false
+
     attr_reader :messages, :details
 
     # Pass in the instance of the object that is using the errors object.
@@ -364,12 +369,51 @@ module ActiveModel
     # Returns a full message for a given attribute.
     #
     #   person.errors.full_message(:name, 'is invalid') # => "Name is invalid"
+    #
+    #   The `"%{attribute} %{message}"` error format can be overridden with either
+    #
+    # * <tt>activemodel.errors.models.person/contacts/addresses.attributes.street.format</tt>
+    # * <tt>activemodel.errors.models.person/contacts/addresses.format</tt>
+    # * <tt>activemodel.errors.models.person.attributes.name.format</tt>
+    # * <tt>activemodel.errors.models.person.format</tt>
+    # * <tt>errors.format</tt>
     def full_message(attribute, message)
       return message if attribute == :base
+
+      if self.class.i18n_full_message && @base.class.respond_to?(:i18n_scope)
+        parts = attribute.to_s.split(".")
+        attribute_name = parts.pop
+        namespace = parts.join("/") unless parts.empty?
+        attributes_scope = "#{@base.class.i18n_scope}.errors.models"
+
+        if namespace
+          defaults = @base.class.lookup_ancestors.map do |klass|
+            [
+              :"#{attributes_scope}.#{klass.model_name.i18n_key}/#{namespace}.attributes.#{attribute_name}.format",
+              :"#{attributes_scope}.#{klass.model_name.i18n_key}/#{namespace}.format",
+            ]
+          end
+        else
+          defaults = @base.class.lookup_ancestors.map do |klass|
+            [
+              :"#{attributes_scope}.#{klass.model_name.i18n_key}.attributes.#{attribute_name}.format",
+              :"#{attributes_scope}.#{klass.model_name.i18n_key}.format",
+            ]
+          end
+        end
+
+        defaults.flatten!
+      else
+        defaults = []
+      end
+
+      defaults << :"errors.format"
+      defaults << "%{attribute} %{message}"
+
       attr_name = attribute.to_s.tr(".", "_").humanize
       attr_name = @base.class.human_attribute_name(attribute, default: attr_name)
-      I18n.t(:"errors.format",
-        default:  "%{attribute} %{message}",
+      I18n.t(defaults.shift,
+        default:  defaults,
         attribute: attr_name,
         message:   message)
     end
diff --git a/activemodel/lib/active_model/railtie.rb b/activemodel/lib/active_model/railtie.rb
index a9cdabba00..0ed70bd473 100644
--- a/activemodel/lib/active_model/railtie.rb
+++ b/activemodel/lib/active_model/railtie.rb
@@ -7,8 +7,14 @@ module ActiveModel
   class Railtie < Rails::Railtie # :nodoc:
     config.eager_load_namespaces << ActiveModel
 
+    config.active_model = ActiveSupport::OrderedOptions.new
+
     initializer "active_model.secure_password" do
       ActiveModel::SecurePassword.min_cost = Rails.env.test?
     end
+
+    initializer "active_model.i18n_full_message" do
+      ActiveModel::Errors.i18n_full_message = config.active_model.delete(:i18n_full_message) || false
+    end
   end
 end