Keep the attribute's name translation as is:

- When an error is added to a record due to
  `restrict_dependent_destroy` error, we were always downcasing its
  attribute name even when an application had specified a translation.

  Now, the attribute's name will be downcased only when no translation
  exists.

  Fix rails#53448

activemodel/lib/active_model/translation.rb

@@ -68,8 +68,9 @@ def human_attribute_name(attribute, options = {})
       defaults << options[:default] if options[:default]
       defaults << MISSING_TRANSLATION unless raise_on_missing
 
+      capitalize_missing_translation = options.delete(:_capitalize) { true }
       translation = I18n.translate(defaults.shift, count: 1, raise: raise_on_missing, **options, default: defaults)
-      translation = attribute.humanize if translation == MISSING_TRANSLATION
+      translation = attribute.humanize(capitalize: capitalize_missing_translation) if translation == MISSING_TRANSLATION
       translation
     end
   end

activerecord/lib/active_record/associations/has_many_association.rb

@@ -18,7 +18,7 @@ def handle_dependency
 
         when :restrict_with_error
           unless empty?
-            record = owner.class.human_attribute_name(reflection.name).downcase
+            record = owner.class.human_attribute_name(reflection.name, _capitalize: false)
             owner.errors.add(:base, :'restrict_dependent_destroy.has_many', record: record)
             throw(:abort)
           end

activerecord/lib/active_record/associations/has_one_association.rb

@@ -13,7 +13,7 @@ def handle_dependency
 
         when :restrict_with_error
           if load_target
-            record = owner.class.human_attribute_name(reflection.name).downcase
+            record = owner.class.human_attribute_name(reflection.name, _capitalize: false)
             owner.errors.add(:base, :'restrict_dependent_destroy.has_one', record: record)
             throw(:abort)
           end

activerecord/test/cases/associations/has_many_associations_test.rb

@@ -2006,7 +2006,7 @@ def test_restrict_with_error
 
   def test_restrict_with_error_with_locale
     I18n.backend = I18n::Backend::Simple.new
-    I18n.backend.store_translations "en", activerecord: { attributes: { restricted_with_error_firm: { companies: "client companies" } } }
+    I18n.backend.store_translations "en", activerecord: { attributes: { restricted_with_error_firm: { companies: "LLC companies" } } }
     firm = RestrictedWithErrorFirm.create!(name: "restrict")
     firm.companies.create(name: "child")
 
@@ -2016,7 +2016,7 @@ def test_restrict_with_error_with_locale
 
     assert_not_empty firm.errors
 
-    assert_equal "Cannot delete record because dependent client companies exist", firm.errors[:base].first
+    assert_equal "Cannot delete record because dependent LLC companies exist", firm.errors[:base].first
     assert RestrictedWithErrorFirm.exists?(name: "restrict")
     assert firm.companies.exists?(name: "child")
   ensure

activerecord/test/cases/associations/has_one_associations_test.rb

@@ -243,7 +243,7 @@ def test_restrict_with_error
 
   def test_restrict_with_error_with_locale
     I18n.backend = I18n::Backend::Simple.new
-    I18n.backend.store_translations "en", activerecord: { attributes: { restricted_with_error_firm: { account: "firm account" } } }
+    I18n.backend.store_translations "en", activerecord: { attributes: { restricted_with_error_firm: { account: "LLC account" } } }
     firm = RestrictedWithErrorFirm.create!(name: "restrict")
     firm.create_account(credit_limit: 10)
 
@@ -252,7 +252,7 @@ def test_restrict_with_error_with_locale
     firm.destroy
 
     assert_not_empty firm.errors
-    assert_equal "Cannot delete record because a dependent firm account exists", firm.errors[:base].first
+    assert_equal "Cannot delete record because a dependent LLC account exists", firm.errors[:base].first
     assert RestrictedWithErrorFirm.exists?(name: "restrict")
     assert_predicate firm.account, :present?
   ensure