Allow empty path for unix socket addresses to represent unnamed addre…

…sses and work around the null domain socket address returned by Netty client channels.

src/main/java/io/vertx/core/impl/transports/KQueueTransport.java

@@ -53,11 +53,7 @@ public SocketAddress convert(io.vertx.core.net.SocketAddress address) {
   @Override
   public io.vertx.core.net.SocketAddress convert(SocketAddress address) {
     if (address instanceof DomainSocketAddress) {
-      String path = ((DomainSocketAddress) address).path();
-      if (path.isEmpty()) {
-        return null;
-      }
-      return new SocketAddressImpl(path);
+      return new SocketAddressImpl(((DomainSocketAddress) address).path());
     }
     return Transport.super.convert(address);
   }

src/main/java/io/vertx/core/net/SocketAddress.java

@@ -125,7 +125,7 @@ static SocketAddress inetSocketAddress(InetSocketAddress address) {
   int port();
 
   /**
-   * @return the domain socket path or {@code null} for a inet socket address.
+   * @return the domain socket path or {@code null} for inet socket address, empty path represents unnamed domain socket addresses.
    */
   @CacheReturn
   String path();

src/main/java/io/vertx/core/net/impl/ConnectionBase.java

@@ -654,6 +654,10 @@ public SocketAddress remoteAddress(boolean real) {
 
   private SocketAddress channelLocalAddress() {
     java.net.SocketAddress addr = chctx.channel().localAddress();
+    if (addr == null && channel().getClass().getSimpleName().endsWith("DomainSocketChannel")) {
+      // Workaround bug https://github.com/netty/netty/issues/13417
+      return SocketAddress.domainSocketAddress("");
+    }
     return addr != null ? vertx.transport().convert(addr) : null;
   }
 

src/main/java/io/vertx/core/net/impl/SocketAddressImpl.java

@@ -82,7 +82,6 @@ public SocketAddressImpl(int port, String host) {
 
   public SocketAddressImpl(String path) {
     Objects.requireNonNull(path, "domain socket path must be non null");
-    Arguments.require(!path.isEmpty(), "domain socket must not be empty");
     this.port = -1;
     this.host = null;
     this.ipAddress = null;

src/test/java/io/vertx/core/net/NetTest.java

@@ -2206,24 +2206,33 @@ public void testFanout() throws Exception {
   }
 
   @Test
-  public void testRemoteAddress() {
+  public void  testSocketAddress() {
     server.connectHandler(socket -> {
-      SocketAddress addr = socket.remoteAddress();
-      assertEquals("127.0.0.1", addr.host());
-      assertEquals(null, addr.hostName());
-      assertEquals("127.0.0.1", addr.hostAddress());
+      SocketAddress addr = socket.localAddress();
+      if (addr.isInetSocket()) {
+        assertEquals("127.0.0.1", addr.host());
+        assertEquals(null, addr.hostName());
+        assertEquals("127.0.0.1", addr.hostAddress());
+      } else {
+        assertEquals(testAddress.path(), addr.path());
+        assertEquals("", socket.remoteAddress().path());
+      }
       socket.close();
-    }).listen(1234, "localhost", ar -> {
-      assertTrue(ar.succeeded());
-      vertx.createNetClient(new NetClientOptions()).connect(1234, "localhost", onSuccess(socket -> {
+    }).listen(1234, "localhost").onComplete(onSuccess(v -> {
+      vertx.createNetClient(new NetClientOptions()).connect(1234, "localhost").onComplete(onSuccess(socket -> {
         SocketAddress addr = socket.remoteAddress();
-        assertEquals("localhost", addr.host());
-        assertEquals("localhost", addr.hostName());
-        assertEquals("127.0.0.1", addr.hostAddress());
-        assertEquals(addr.port(), 1234);
-        socket.closeHandler(v -> testComplete());
+        if (addr.isInetSocket()) {
+          assertEquals("localhost", addr.host());
+          assertEquals("localhost", addr.hostName());
+          assertEquals("127.0.0.1", addr.hostAddress());
+          assertEquals(addr.port(), 1234);
+        } else {
+          assertEquals(testAddress.path(), addr.path());
+          assertEquals("", socket.localAddress().path());
+        }
+        socket.closeHandler(v2 -> testComplete());
       }));
-    });
+    }));
     await();
   }
 
@@ -4324,10 +4333,14 @@ private void testHAProxyProtocolAccepted(Buffer header, SocketAddress remote, So
     server = vertx.createNetServer(new NetServerOptions()
       .setUseProxyProtocol(true))
       .connectHandler(so -> {
-        SocketAddress ra = so.remoteAddress();
-        SocketAddress la = so.localAddress();
-        assertAddresses(remote == null && testAddress.isInetSocket() ? proxy.getConnectionLocalAddress() : remote, ra);
-        assertAddresses(local == null && testAddress.isInetSocket() ? proxy.getConnectionRemoteAddress() : local, la);
+        assertAddresses(remote == null && testAddress.isInetSocket() ?
+            proxy.getConnectionLocalAddress() :
+            remote,
+          so.remoteAddress());
+        assertAddresses(local == null && testAddress.isInetSocket() ?
+            proxy.getConnectionRemoteAddress() :
+            local,
+          so.localAddress());
         complete();
       });
     startServer();