Fixes "Cached fragment hit" written to log even if fragment is not cached (Erik Andrejko) [#2917 state:resolved]

actionpack/lib/action_controller/caching/fragments.rb

@@ -36,8 +36,8 @@ def fragment_cache_key(key)
 
       def fragment_for(buffer, name = {}, options = nil, &block) #:nodoc:
         if perform_caching
-          if cache = read_fragment(name, options)
-            buffer.concat(cache)
+          if fragment_exist?(name,options)
+            buffer.concat(read_fragment(name, options))
           else
             pos = buffer.length
             block.call

actionpack/test/controller/caching_test.rb

@@ -625,6 +625,21 @@ def test_fragment_for
     assert !fragment_computed
     assert_equal 'generated till now -> fragment content', buffer
   end
+
+  def test_fragment_for_logging
+    fragment_computed = false
+
+    @controller.class.expects(:benchmark).with('Cached fragment exists?: views/expensive')
+    @controller.class.expects(:benchmark).with('Cached fragment miss: views/expensive')
+    @controller.class.expects(:benchmark).with('Cached fragment hit: views/expensive').never
+
+    buffer = 'generated till now -> '
+    @controller.fragment_for(buffer, 'expensive') { fragment_computed = true }
+
+    assert fragment_computed
+    assert_equal 'generated till now -> ', buffer
+  end
+
 end
 
 class FunctionalCachingController < ActionController::Base