Merge pull request rails#54266 from zzak/re-54250

Handle missing attributes for AM::Translation#human_attribute_name

Author: byroot

activemodel/lib/active_model/translation.rb

@@ -52,10 +52,19 @@ def human_attribute_name(attribute, options = {})
         namespace, _, attribute = attribute.rpartition(".")
         namespace.tr!(".", "/")
 
+        if attribute.present?
+          key = "#{namespace}.#{attribute}"
+          separator = "/"
+        else
+          key = namespace
+          separator = "."
+        end
+
         defaults = lookup_ancestors.map do |klass|
-          :"#{i18n_scope}.attributes.#{klass.model_name.i18n_key}/#{namespace}.#{attribute}"
+          :"#{i18n_scope}.attributes.#{klass.model_name.i18n_key}#{separator}#{key}"
         end
-        defaults << :"#{i18n_scope}.attributes.#{namespace}.#{attribute}"
+        defaults << :"#{i18n_scope}.attributes.#{key}"
+        defaults << :"attributes.#{key}"
       else
         defaults = lookup_ancestors.map do |klass|
           :"#{i18n_scope}.attributes.#{klass.model_name.i18n_key}.#{attribute}"
@@ -69,7 +78,9 @@ def human_attribute_name(attribute, options = {})
       defaults << MISSING_TRANSLATION unless raise_on_missing
 
       translation = I18n.translate(defaults.shift, count: 1, raise: raise_on_missing, **options, default: defaults)
-      translation = attribute.humanize if translation == MISSING_TRANSLATION
+      if translation == MISSING_TRANSLATION
+        translation = attribute.present? ? attribute.humanize : namespace.humanize
+      end
       translation
     end
   end

activemodel/test/cases/translation_test.rb

@@ -104,6 +104,16 @@ def test_translated_subclass_model_when_ancestor_translation
     assert_equal "person model", Child.model_name.human
   end
 
+  def test_translated_attributes_when_nil
+    I18n.backend.store_translations "en", activemodel: { attributes: { "person/addresses": { street: "Person Address Street" } } }
+    assert_equal("Addresses", Person.human_attribute_name("addresses.#{nil}"))
+  end
+
+  def test_translated_deeply_nested_attributes_when_nil
+    I18n.backend.store_translations "en", activemodel: { attributes: { "person/contacts/addresses": { street: "Deeply Nested Address Street" } } }
+    assert_equal("Addresses/contacts", Person.human_attribute_name("addresses.contacts.#{nil}"))
+  end
+
   def test_translated_subclass_model_when_missing_translation
     assert_equal "Child", Child.model_name.human
   end