Halting a before block should stop processing

Before this, we continued processing other before blocks
and routes after a before block threw :halt.

lib/sinatra/base.rb

@@ -328,7 +328,11 @@ module Sinatra
 
   private
     def dispatch!
-      self.class.filters.each { |block| invoke(block) }
+      self.class.filters.each do |block|
+        res = catch(:halt) { instance_eval(&block) ; :continue }
+        return unless res == :continue
+      end
+
       if routes = self.class.routes[@request.request_method]
         path = @request.path_info
         original_params = nested_params(@request.params)
@@ -408,6 +412,7 @@ module Sinatra
       when (100...599) === res
         @response.status = res
       end
+
       res
     end
 
@@ -522,7 +527,7 @@ module Sinatra
       end
 
       def before(&block)
-        @filters << lambda { instance_eval(&block) ; nil }
+        @filters << block
       end
 
       def condition(&block)

test/filter_test.rb

@@ -33,15 +33,30 @@ describe "Filters" do
     assert_equal 'bar', body
   end
 
+  it "can modify instance variables available to routes" do
+    mock_app {
+      before { @foo = 'bar' }
+      get('/foo') { @foo }
+    }
+
+    get '/foo'
+    assert ok?
+    assert_equal 'bar', body
+  end
+
   it "allows redirects in filters" do
     mock_app {
       before { redirect '/bar' }
-      get('/foo') { 'ORLY?!' }
+      get('/foo') do
+        fail 'before block should have halted processing'
+        'ORLY?!'
+      end
     }
 
     get '/foo'
     assert redirect?
     assert_equal '/bar', response['Location']
+    assert_equal '', body
   end
 
   it "does not modify the response with its return value" do