Backport Allow ndots=0, close AsyncHttpClient#1219

Author: slandelle

netty-bp/resolver-dns/src/main/java/io/netty/resolver/dns/DnsNameResolver.java

@@ -190,7 +190,7 @@ public DnsNameResolver(
         this.hostsFileEntriesResolver = checkNotNull(hostsFileEntriesResolver, "hostsFileEntriesResolver");
         this.resolveCache = resolveCache;
         this.searchDomains = checkNotNull(searchDomains, "searchDomains").clone();
-        this.ndots = checkPositive(ndots, "ndots");
+        this.ndots = checkPositiveOrZero(ndots, "ndots");
 
         Bootstrap b = new Bootstrap();
         b.group(executor());

netty-bp/resolver-dns/src/main/java/io/netty/resolver/dns/DnsNameResolverBuilder.java

@@ -319,6 +319,7 @@ public DnsNameResolverBuilder searchDomains(Iterable<String> searchDomains) {
 
   /**
    * Set the number of dots which must appear in a name before an initial absolute query is made.
+   * The default value is {@code 1}.
    *
    * @param ndots the ndots value
    * @return {@code this}

netty-bp/resolver-dns/src/main/java/io/netty/resolver/dns/DnsNameResolverContext.java

@@ -124,14 +124,18 @@ public void operationComplete(Future<T> future) throws Exception {
                     }
                 }
             });
-            int dots = 0;
-            for (int idx = hostname.length() - 1; idx >= 0; idx--) {
-                if (hostname.charAt(idx) == '.' && ++dots >= parent.ndots()) {
-                    internalResolve(promise);
-                    return;
-                }
-            }
-            promise.tryFailure(new UnknownHostException(hostname));
+            if (parent.ndots() == 0) {
+                internalResolve(promise);
+            } else {
+                int dots = 0;
+                for (int idx = hostname.length() - 1; idx >= 0; idx--) {
+                    if (hostname.charAt(idx) == '.' && ++dots >= parent.ndots()) {
+                        internalResolve(promise);
+                        return;
+                    }
+                 }
+                 promise.tryFailure(new UnknownHostException(hostname));
+             }
         }
     }
 

netty-bp/resolver-dns/src/test/java/io/netty/resolver/dns/SearchDomainTest.java

@@ -48,6 +48,7 @@ private DnsNameResolverBuilder newResolver() {
 
     private TestDnsServer dnsServer;
     private EventLoopGroup group;
+    private DnsNameResolver resolver;
 
     @Before
     public void before() {
@@ -60,6 +61,9 @@ public void destroy() {
             dnsServer.stop();
             dnsServer = null;
         }
+        if (resolver != null) {
+            resolver.close();
+        }
         group.shutdownGracefully();
     }
 
@@ -77,7 +81,7 @@ public void testResolve() throws Exception {
         dnsServer = new TestDnsServer(store);
         dnsServer.start();
 
-        DnsNameResolver resolver = newResolver().searchDomains(Collections.singletonList("foo.com")).build();
+        resolver = newResolver().searchDomains(Collections.singletonList("foo.com")).build();
 
         String a = "host1.foo.com";
         String resolved = assertResolve(resolver, a);
@@ -124,7 +128,7 @@ public void testResolveAll() throws Exception {
         dnsServer = new TestDnsServer(store);
         dnsServer.start();
 
-        DnsNameResolver resolver = newResolver().searchDomains(Collections.singletonList("foo.com")).build();
+        resolver = newResolver().searchDomains(Collections.singletonList("foo.com")).build();
 
         String a = "host1.foo.com";
         List<String> resolved = assertResolveAll(resolver, a);
@@ -169,7 +173,7 @@ public void testMultipleSearchDomain() throws Exception {
         dnsServer = new TestDnsServer(store);
         dnsServer.start();
 
-        DnsNameResolver resolver = newResolver().searchDomains(Arrays.asList("foo.com", "bar.com")).build();
+        resolver = newResolver().searchDomains(Arrays.asList("foo.com", "bar.com")).build();
 
         // "host1" resolves via the "foo.com" search path
         String resolved = assertResolve(resolver, "host1");
@@ -198,7 +202,7 @@ public void testSearchDomainWithNdots2() throws Exception {
         dnsServer = new TestDnsServer(store);
         dnsServer.start();
 
-        DnsNameResolver resolver = newResolver().searchDomains(Collections.singleton("foo.com")).ndots(2).build();
+        resolver = newResolver().searchDomains(Collections.singleton("foo.com")).ndots(2).build();
 
         String resolved = assertResolve(resolver, "host1.sub");
         assertEquals(store.getAddress("host1.sub.foo.com"), resolved);
@@ -208,6 +212,32 @@ public void testSearchDomainWithNdots2() throws Exception {
         assertEquals(store.getAddress("host2.sub.foo.com"), resolved);
     }
 
+    @Test
+    public void testSearchDomainWithNdots0() throws Exception {
+        Set<String> domains = new HashSet<String>();
+        domains.add("host1");
+        domains.add("host1.foo.com");
+        domains.add("host2.foo.com");
+
+        TestDnsServer.MapRecordStoreA store = new TestDnsServer.MapRecordStoreA(domains);
+        dnsServer = new TestDnsServer(store);
+        dnsServer.start();
+
+        resolver = newResolver().searchDomains(Collections.singleton("foo.com")).ndots(0).build();
+
+        // "host1" resolves directly as ndots = 0
+        String resolved = assertResolve(resolver, "host1");
+        assertEquals(store.getAddress("host1"), resolved);
+
+        // "host1.foo.com" resolves to host1.foo
+        resolved = assertResolve(resolver, "host1.foo.com");
+        assertEquals(store.getAddress("host1.foo.com"), resolved);
+
+        // "host2" resolves to host2.foo.com with the foo.com search domain
+        resolved = assertResolve(resolver, "host2");
+        assertEquals(store.getAddress("host2.foo.com"), resolved);
+    }
+
     private void assertNotResolve(DnsNameResolver resolver, String inetHost) throws InterruptedException {
         Future<InetAddress> fut = resolver.resolve(inetHost);
         assertTrue(fut.await(10, TimeUnit.SECONDS));