More checks for nodes without node objects.

When a NodeAction was queried for which nodes were applicable, it
filtered out nodes that didn't have a nodeObject.
However, when a NodeRequest is similarly queried, null nodeObjects
were not filtered out and I guess it was up to the NodeRequest to
say "no" to null nodeObjects. This is not part of the API specification
for NodeApplicant, and in Spiral Knights we have various requests/actions
that simply return true without regard to the contents of the nodeObject.

So that's fucking retarded. Do the null check just like it's done
for NodeActions. In addition, do an extra check if one of single-node
methods is called for an action or request, to make sure that one
pre-determined node has a nodeObject set up. If not, log a warning,
and return an error response in the NodeRequest case.

core/src/main/java/com/threerings/presents/peer/server/PeerManager.java

@@ -62,6 +62,7 @@ import com.threerings.presents.annotation.PeerInvoker;
 import com.threerings.presents.client.Client;
 import com.threerings.presents.client.InvocationService;
 import com.threerings.presents.data.ClientObject;
+import com.threerings.presents.data.InvocationCodes;
 import com.threerings.presents.dobj.DObject;
 import com.threerings.presents.dobj.ObjectAccessException;
 import com.threerings.presents.dobj.Subscriber;
@@ -320,9 +321,9 @@ public abstract class PeerManager
         String nodeName, String sharedSecret, String hostName, String publicHostName,
         String region, int port, String nodeNamespace)
     {
-        _nodeNamespace = nodeNamespace;
         _nodeName = nodeName;
         _sharedSecret = sharedSecret;
+        _nodeNamespace = nodeNamespace;
 
         // wire ourselves into the server
         _conmgr.addChainedAuthenticator(
@@ -494,7 +495,12 @@ public abstract class PeerManager
     {
         PeerNode peer = _peers.get(nodeName);
         if (peer != null) {
+            if (peer.nodeobj != null) {
                 peer.nodeobj.peerService.invokeAction(flattenAction(action));
+            } else {
+                log.warning("Dropped NodeAction", "nodeName", nodeName, "action", action);
+            }
+
         } else if (Objects.equal(nodeName, _nodeName)) {
             invokeAction(null, flattenAction(action));
         }
@@ -566,7 +572,7 @@ public abstract class PeerManager
             nodes.add(_nodeobj.nodeName);
         }
         for (PeerNode peer : _peers.values()) {
-            if (applicant.isApplicable(peer.nodeobj)) {
+            if (peer.nodeobj != null && applicant.isApplicable(peer.nodeobj)) {
                 nodes.add(peer.getNodeName());
             }
         }
@@ -1508,7 +1514,14 @@ public abstract class PeerManager
     {
         PeerNode peer = _peers.get(nodeName);
         if (peer != null) {
+            if (peer.nodeobj != null) {
                 peer.nodeobj.peerService.invokeRequest(requestBytes, listener);
+
+            } else {
+                log.warning("Dropped NodeRequest", "nodeName", nodeName);
+                listener.requestFailed(InvocationCodes.INTERNAL_ERROR);
+            }
+
         } else if (Objects.equal(nodeName, _nodeName)) {
             invokeRequest(null, requestBytes, listener);
         }