Rack::Lock should unlock if the app raises an exception.

lib/rack/lock.rb

@@ -26,6 +26,9 @@ def call(env)
       response = @app.call(env)
       response[2] = Proxy.new(response[2], @mutex)
       response
+    rescue Exception
+      @mutex.unlock
+      raise
     ensure
       env[FLAG] = old
     end

test/spec_lock.rb

@@ -88,6 +88,14 @@ def close; @close_called = true; end
     lock.synchronized.should.equal true
   end
 
+  should "unlock if the app raises" do
+    lock = Lock.new
+    env = Rack::MockRequest.env_for("/")
+    app = Rack::Lock.new(lambda { raise Exception }, lock)
+    lambda { app.call(env) }.should.raise(Exception)
+    lock.synchronized.should.equal false
+  end
+
   should "set multithread flag to false" do
     app = Rack::Lock.new(lambda { |env|
       env['rack.multithread'].should.equal false