From 5745a5e85e1900c52d169f79ec0802060e110e21 Mon Sep 17 00:00:00 2001
From: Colin MacKenzie IV <sinisterchipmunk@gmail.com>
Date: Wed, 2 Nov 2011 09:00:18 -0400
Subject: [PATCH] treat USAGE as an ERB template

---
 railties/lib/rails/generators/base.rb                       | 2 +-
 railties/test/fixtures/lib/generators/usage_template/USAGE  | 1 +
 .../generators/usage_template/usage_template_generator.rb   | 5 +++++
 railties/test/generators_test.rb                            | 6 ++++++
 4 files changed, 13 insertions(+), 1 deletion(-)
 create mode 100644 railties/test/fixtures/lib/generators/usage_template/USAGE
 create mode 100644 railties/test/fixtures/lib/generators/usage_template/usage_template_generator.rb

diff --git a/railties/lib/rails/generators/base.rb b/railties/lib/rails/generators/base.rb
index 911f80cf3a..f38a487a4e 100644
--- a/railties/lib/rails/generators/base.rb
+++ b/railties/lib/rails/generators/base.rb
@@ -34,7 +34,7 @@ module Rails
         usage = source_root && File.expand_path("../USAGE", source_root)
 
         @desc ||= if usage && File.exist?(usage)
-          File.read(usage)
+          ERB.new(File.read(usage)).result(binding)
         else
           "Description:\n    Create #{base_name.humanize.downcase} files for #{generator_name} generator."
         end
diff --git a/railties/test/fixtures/lib/generators/usage_template/USAGE b/railties/test/fixtures/lib/generators/usage_template/USAGE
new file mode 100644
index 0000000000..bcd63c52e2
--- /dev/null
+++ b/railties/test/fixtures/lib/generators/usage_template/USAGE
@@ -0,0 +1 @@
+:: <%= 1 + 1 %> ::
\ No newline at end of file
diff --git a/railties/test/fixtures/lib/generators/usage_template/usage_template_generator.rb b/railties/test/fixtures/lib/generators/usage_template/usage_template_generator.rb
new file mode 100644
index 0000000000..078b0f9412
--- /dev/null
+++ b/railties/test/fixtures/lib/generators/usage_template/usage_template_generator.rb
@@ -0,0 +1,5 @@
+require 'rails/generators'
+
+class UsageTemplateGenerator < Rails::Generators::Base
+  source_root File.expand_path("templates", File.dirname(__FILE__))
+end
diff --git a/railties/test/generators_test.rb b/railties/test/generators_test.rb
index 56329f3183..5f9ee220dc 100644
--- a/railties/test/generators_test.rb
+++ b/railties/test/generators_test.rb
@@ -201,4 +201,10 @@ class GeneratorsTest < Rails::Generators::TestCase
     mspec = Rails::Generators.find_by_namespace :fixjour
     assert mspec.source_paths.include?(File.join(Rails.root, "lib", "templates", "fixjour"))
   end
+  
+  def test_usage_with_embedded_ruby
+    require File.expand_path("fixtures/lib/generators/usage_template/usage_template_generator", File.dirname(__FILE__))
+    output = capture(:stdout) { Rails::Generators.invoke :usage_template, ['--help'] }
+    assert_match /:: 2 ::/, output
+  end
 end