[2282] cover the case of coexistence of DNAME and additional.

added one more test for that.

src/lib/datasrc/memory/zone_finder.cc

@@ -673,12 +673,17 @@ InMemoryZoneFinder::Context::findAdditional(
         return;
     }
 
-    // Ignore data at a zone cut unless glue is allowed.
-    // TODO: DNAME case consideration (with test)
+    // Ignore data at a zone cut (due to subdomain delegation) unless glue is
+    // allowed.  Checking the node callback flag is a cheap way to detect
+    // zone cuts, but it includes DNAME delegation, in which case we should
+    // keep finding the additional records regardless of the 'GLUE_OK' flag.
+    // The last two conditions limit the case to delegation NS, i.e, the node
+    // has an NS and it's not the zone origin.
     const ZoneNode* node = node_result.node;
     if ((options & ZoneFinder::FIND_GLUE_OK) == 0 &&
         node->getFlag(ZoneNode::FLAG_CALLBACK) &&
-        node != zone_data_->getOriginNode()) {
+        node != zone_data_->getOriginNode() &&
+        RdataSet::find(node->getData(), RRType::NS()) != NULL) {
         return;
     }
 

src/lib/datasrc/tests/testdata/contexttest.zone

@@ -1,7 +1,7 @@
 ;; test zone file used for ZoneFinderContext tests.
 ;; RRSIGs are (obviouslly) faked ones for testing.
 
-example.org. 3600 IN SOA	ns1.example.org. bugs.x.w.example.org. 67 3600 300 3600000 3600
+example.org. 3600 IN SOA	ns1.example.org. bugs.x.w.example.org. 71 3600 300 3600000 3600
 example.org.			      3600 IN NS	ns1.example.org.
 example.org.			      3600 IN NS	ns2.example.org.
 example.org.			      3600 IN MX	1 mx1.example.org.
@@ -71,6 +71,9 @@ a.*.emptywild.example.org.    3600 IN AAAA	2001:db8::2
 ;; expansion
 *.wildmx.example.org. 3600 IN MX 1 mx1.example.org.
 
+;; the owner name of additional for an answer RRset (MX) has DNAME
+dnamemx.example.org. 3600 IN MX 1 dname.example.org.
+
 ;; CNAME
 alias.example.org. 3600 IN CNAME cname.example.org.
 

src/lib/datasrc/tests/zone_finder_context_unittest.cc

@@ -235,6 +235,18 @@ TEST_P(ZoneFinderContextTest, getAdditionalDelegationWithDname) {
                 result_sets_.begin(), result_sets_.end());
 }
 
+TEST_P(ZoneFinderContextTest, getAdditionalOnDname) {
+    // The additional name has a DNAME as well as the additional record.
+    // The existence of DNAME shouldn't hide the additional record.
+    ZoneFinderContextPtr ctx = finder_->find(Name("dnamemx.example.org"),
+                                             RRType::MX());
+    EXPECT_EQ(ZoneFinder::SUCCESS, ctx->code);
+
+    ctx->getAdditional(REQUESTED_BOTH, result_sets_);
+    rrsetsCheck("dname.example.org. 3600 IN A 192.0.2.12\n",
+                result_sets_.begin(), result_sets_.end());
+}
+
 TEST_P(ZoneFinderContextTest, getAdditionalDelegationWithEmptyName) {
     // One of NS names is at an empty non terminal node.  It shouldn't cause
     // any disruption.