ActionMailer: support overriding template name in multipart

Implicit rendering in multipart blocks now also uses the template
name from the options hash instead of always using the action name.

So you can now write

    mail(template_name: template_name) do |format|
      format.text
      format.html
    end

1 files changed, 8 insertions, 3 deletions

diff --git a/actionmailer/lib/action_mailer/base.rb b/actionmailer/lib/action_mailer/base.rb
index cbbf480da8..9dd3f151ad 100644
--- a/actionmailer/lib/action_mailer/base.rb
+++ b/actionmailer/lib/action_mailer/base.rb
@@ -893,9 +893,7 @@ module ActionMailer
 
     def collect_responses(headers)
       if block_given?
-        collector = ActionMailer::Collector.new(lookup_context) { render(action_name) }
-        yield(collector)
-        collector.responses
+        collect_responses_from_block(headers, &Proc.new)
       elsif headers[:body]
         [{
           body: headers.delete(:body),
@@ -906,6 +904,13 @@ module ActionMailer
       end
     end
 
+    def collect_responses_from_block(headers)
+      templates_name = headers[:template_name] || action_name
+      collector = ActionMailer::Collector.new(lookup_context) { render(templates_name) }
+      yield(collector)
+      collector.responses
+    end
+
     def collect_responses_from_templates(headers)
       templates_path = headers[:template_path] || self.class.mailer_name
       templates_name = headers[:template_name] || action_name