[2013] (related bug fix) make Message::clearSection clear questions correctly.

this fix is necessary for ddns to make responses correctly.

src/lib/dns/message.cc

@@ -573,7 +573,11 @@ Message::clearSection(const Section section) {
     if (section >= MessageImpl::NUM_SECTIONS) {
         isc_throw(OutOfRange, "Invalid message section: " << section);
     }
-    impl_->rrsets_[section].clear();
+    if (section == Message::SECTION_QUESTION) {
+        impl_->questions_.clear();
+    } else {
+        impl_->rrsets_[section].clear();
+    }
     impl_->counts_[section] = 0;
 }
 

src/lib/dns/python/tests/message_python_test.py

@@ -295,6 +295,7 @@ class MessageTest(unittest.TestCase):
         self.assertEqual(1, self.r.get_rr_count(Message.SECTION_QUESTION))
         self.r.clear_section(Message.SECTION_QUESTION)
         self.assertEqual(0, self.r.get_rr_count(Message.SECTION_QUESTION))
+        self.assertEqual(0, len(self.r.get_question()))
 
     def test_clear_section(self):
         for section in [Message.SECTION_ANSWER, Message.SECTION_AUTHORITY,

src/lib/dns/tests/message_unittest.cc

@@ -406,6 +406,8 @@ TEST_F(MessageTest, clearQuestionSection) {
 
     message_render.clearSection(Message::SECTION_QUESTION);
     EXPECT_EQ(0, message_render.getRRCount(Message::SECTION_QUESTION));
+    EXPECT_TRUE(message_render.beginQuestion() ==
+                message_render.endQuestion());
 }