Merge pull request #1296 from fluent/fix-bug-not-to-overwrite-default…

…-value-with-nil

Fix a bug not to overwrite default value with nil

lib/fluent/configurable.rb

@@ -71,9 +71,7 @@ def configure(conf)
       root.instance_eval{ @params.keys }.each do |param_name|
         next if param_name.to_s.start_with?('@')
         varname = "@#{param_name}".to_sym
-        if (! root[param_name].nil?) || (instance_variable_defined?(varname) && instance_variable_get(varname).nil?)
-          instance_variable_set(varname, root[param_name])
-        end
+        instance_variable_set(varname, root[param_name])
       end
 
       self

lib/fluent/plugin/out_exec_filter.rb

@@ -96,20 +96,20 @@ def initialize
     def configure(conf)
       if tag_key = conf['tag_key']
         # TODO obsoleted?
-        @in_tag_key = tag_key
-        @out_tag_key = tag_key
+        conf['in_tag_key'] = tag_key
+        conf['out_tag_key'] = tag_key
       end
 
       if time_key = conf['time_key']
         # TODO obsoleted?
-        @in_time_key = time_key
-        @out_time_key = time_key
+        conf['in_time_key'] = time_key
+        conf['out_time_key'] = time_key
       end
 
       if time_format = conf['time_format']
         # TODO obsoleted?
-        @in_time_format = time_format
-        @out_time_format = time_format
+        conf['in_time_format'] = time_format
+        conf['out_time_format'] = time_format
       end
 
       super

test/config/test_configurable.rb

@@ -334,6 +334,12 @@ class SubOwner < Owner
       end
     end
 
+    class NilOwner < Owner
+      config_section :buffer do
+        config_set_default :size_of_something, nil
+      end
+    end
+
     class FlatChild
       include Fluent::Configurable
       attr_accessor :owner
@@ -1078,6 +1084,16 @@ class TestConfigurable < ::Test::Unit::TestCase
         assert_equal 2048, child.size_of_something
       end
 
+      test 'default values can be overwritten with nil' do
+        owner = ConfigurableSpec::OverwriteDefaults::NilOwner.new
+        child = ConfigurableSpec::OverwriteDefaults::BufferChild.new
+        assert_equal :buffer, child.class.merged_configure_proxy.configured_in_section
+
+        child.owner = owner
+        child.configure(config_element('ROOT', '', {}, []))
+        assert_nil child.size_of_something
+      end
+
       test 'the first configured_in (in the order from base class) will be applied' do
         child = ConfigurableSpec::OverwriteDefaults::BufferSubclass.new
         assert_equal :buffer, child.class.merged_configure_proxy.configured_in_section