Allow passing interpolations to `#default_i18n_subject`, e.g.:

    # config/locales/en.yml
    en:
      user_mailer:
        welcome:
          subject: 'Hello, %{username}'

    # app/mailers/user_mailer.rb
    class UserMailer < ActionMailer::Base
      def welcome(user)
        mail(subject: default_i18n_subject(username: user.name))
      end
    end

1 files changed, 18 insertions, 1 deletions

diff --git a/actionmailer/CHANGELOG.md b/actionmailer/CHANGELOG.md
index 43bfa536c1..7e57fb39f3 100644
--- a/actionmailer/CHANGELOG.md
+++ b/actionmailer/CHANGELOG.md
@@ -1,6 +1,23 @@
 ## Rails 4.0.0 (unreleased) ##
 
-*   Eager loading made to use relation's in_clause_length instead of host's one.
+*   Allow passing interpolations to `#default_i18n_subject`, e.g.:
+
+        # config/locales/en.yml
+        en:
+          user_mailer:
+            welcome:
+              subject: 'Hello, %{username}'
+
+        # app/mailers/user_mailer.rb
+        class UserMailer < ActionMailer::Base
+          def welcome(user)
+            mail(subject: default_i18n_subject(username: user.name))
+          end
+        end
+
+    *Olek Janiszewski*
+
+*   Eager loading made to use relation's `in_clause_length` instead of host's one.
     Fix #8474
 
     *Boris Staal*