Make ActionDispatch::Journey::Path::Pattern#new raise more meaningful exception message.

actionpack/CHANGELOG.md

@@ -1,5 +1,7 @@
 ## Rails 4.0.0.beta1 (February 25, 2013) ##
 
+*   Make ActionDispatch::Journey::Path::Pattern#new raise more meaningful exception message. *Thierry Zires*
+
 *   Fix `respond_to` not using formats that have no block if all is present. *Michael Grosser*
 
 *   New applications use an encrypted session store by default.

actionpack/lib/action_dispatch/journey/path/pattern.rb

@@ -20,7 +20,7 @@ module ActionDispatch
             @separators   = strexp.separators.join
             @anchored     = strexp.anchor
           else
-            raise "wtf bro: #{strexp}"
+            raise ArgumentError, "Bad expression: #{strexp}"
           end
 
           @names          = nil

actionpack/test/journey/path/pattern_test.rb

@@ -75,6 +75,10 @@ module ActionDispatch
           end
         end
 
+        def test_to_raise_exception_with_bad_expression
+          assert_raise(ArgumentError, "Bad expression: []") { Pattern.new [] }
+        end
+
         def test_to_regexp_with_extended_group
           strexp = Router::Strexp.new(
             '/page/:name',