Merge pull request #35424 from Korri/validation-rules-locale-fallback

Fall back to parent locale before falling back to the :errors namespace

2 files changed, 38 insertions, 9 deletions

diff --git a/activemodel/CHANGELOG.md b/activemodel/CHANGELOG.md
index a644c63992..d7586f60ed 100644
--- a/activemodel/CHANGELOG.md
+++ b/activemodel/CHANGELOG.md
@@ -1,3 +1,27 @@
+
+*   Changed how validation error translation strings are fetched: The new behaviour
+    will first try the more specific keys, including doing locale fallback, then try
+    the less specific ones.
+    
+    For example this is the order keys will now be tried for a `blank` error on a
+    `product`'s `title` attribute with current locale set to `en-US`:
+ 
+        en-US.activerecord.errors.models.product.attributes.title.blank
+        en-US.activerecord.errors.models.product.blank
+        en-US.activerecord.errors.messages.blank
+        
+        en.activerecord.errors.models.product.attributes.title.blank
+        en.activerecord.errors.models.product.blank
+        en.activerecord.errors.messages.blank
+        
+        en-US.errors.attributes.title.blank
+        en-US.errors.messages.blank
+        
+        en.errors.attributes.title.blank
+        en.errors.messages.blank
+ 
+    *Hugo Vacher*
+
 ## Rails 6.0.0.beta2 (February 25, 2019) ##
 
 *   Fix date value when casting a multiparameter date hash to not convert
diff --git a/activemodel/lib/active_model/errors.rb b/activemodel/lib/active_model/errors.rb
index 9fd6f2d89c..d7e682d406 100644
--- a/activemodel/lib/active_model/errors.rb
+++ b/activemodel/lib/active_model/errors.rb
@@ -479,6 +479,14 @@ module ActiveModel
     # * <tt>errors.messages.blank</tt>
     def generate_message(attribute, type = :invalid, options = {})
       type = options.delete(:message) if options[:message].is_a?(Symbol)
+      value = (attribute != :base ? @base.send(:read_attribute_for_validation, attribute) : nil)
+
+      options = {
+        model: @base.model_name.human,
+        attribute: @base.class.human_attribute_name(attribute),
+        value: value,
+        object: @base
+      }.merge!(options)
 
       if @base.class.respond_to?(:i18n_scope)
         i18n_scope = @base.class.i18n_scope.to_s
@@ -487,6 +495,11 @@ module ActiveModel
             :"#{i18n_scope}.errors.models.#{klass.model_name.i18n_key}.#{type}" ]
         end
         defaults << :"#{i18n_scope}.errors.messages.#{type}"
+
+        catch(:exception) do
+          translation = I18n.translate(defaults.first, options.merge(default: defaults.drop(1), throw: true))
+          return translation unless translation.nil?
+        end unless options[:message]
       else
         defaults = []
       end
@@ -496,15 +509,7 @@ module ActiveModel
 
       key = defaults.shift
       defaults = options.delete(:message) if options[:message]
-      value = (attribute != :base ? @base.send(:read_attribute_for_validation, attribute) : nil)
-
-      options = {
-        default: defaults,
-        model: @base.model_name.human,
-        attribute: @base.class.human_attribute_name(attribute),
-        value: value,
-        object: @base
-      }.merge!(options)
+      options[:default] = defaults
 
       I18n.translate(key, options)
     end