raise an error if no implicit mailer template could be found

actionmailer/CHANGELOG.md

@@ -1,3 +1,7 @@
+## Rails 4.0.0 (unreleased) ##
+
+* Raise an `ActionView::MissingTemplate` exception when no implicit template could be found. *Damien Mathieu*
+
 ## Rails 3.2.5 (Jun 1, 2012) ##
 
 *   No changes.

actionmailer/lib/action_mailer/base.rb

@@ -184,6 +184,16 @@ module ActionMailer #:nodoc:
   # and the second being a <tt>application/pdf</tt> with a Base64 encoded copy of the file.pdf book
   # with the filename +free_book.pdf+.
   #
+  # If you need to send attachments with no content, you need to create an empty view for it,
+  # or add an empty body parameter like this:
+  #
+  #     class ApplicationMailer < ActionMailer::Base
+  #       def welcome(recipient)
+  #         attachments['free_book.pdf'] = File.read('path/to/file.pdf')
+  #         mail(:to => recipient, :subject => "New account information", :body => "")
+  #       end
+  #     end
+  #
   # = Inline Attachments
   #
   # You can also specify that a file should be displayed inline with other HTML. This is useful
@@ -598,8 +608,10 @@ module ActionMailer #:nodoc:
     #     end
     #   end
     #
-    # Will look for all templates at "app/views/notifier" with name "welcome". However, those
-    # can be customized:
+    # Will look for all templates at "app/views/notifier" with name "welcome".
+    # If no welcome template exists, it will raise an ActionView::MissingTemplate error.
+    #
+    # However, those can be customized:
     #
     #   mail(:template_path => 'notifications', :template_name => 'another')
     #
@@ -733,7 +745,11 @@ module ActionMailer #:nodoc:
 
     def each_template(paths, name, &block) #:nodoc:
       templates = lookup_context.find_all(name, Array(paths))
-      templates.uniq { |t| t.formats }.each(&block)
+      if templates.empty?
+        raise ActionView::MissingTemplate.new([paths], name, [paths], false, 'mailer')
+      else
+        templates.uniq { |t| t.formats }.each(&block)
+      end
     end
 
     def create_parts_from_responses(m, responses) #:nodoc:

actionmailer/test/base_test.rb

@@ -433,6 +433,13 @@ class BaseTest < ActiveSupport::TestCase
     assert_equal("TEXT Implicit Multipart", mail.text_part.body.decoded)
   end
 
+  test "should raise if missing template in implicit render" do
+    assert_raises ActionView::MissingTemplate do
+      BaseMailer.implicit_different_template('missing_template').deliver
+    end
+    assert_equal(0, BaseMailer.deliveries.length)
+  end
+
   test "you can specify a different template for explicit render" do
     mail = BaseMailer.explicit_different_template('explicit_multipart_templates').deliver
     assert_equal("HTML Explicit Multipart Templates", mail.html_part.body.decoded)