code review 163083: fix segfault printing errors. add test case and improve...

src/pkg/rpc/server.go

 // Copyright 2009 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
 /*
         The rpc package provides access to the public methods of an object across a
         network or other I/O connection.  A server registers an object, making it visible
         as a service with the name of the type of the object.  After registration, public
         methods of the object will be accessible remotely.  A server may register multiple
         objects (services) of different types but it is an error to register multiple
@@ skipping 196 matching lines @@
                         continue
                 }
                 // Method needs three ins: receiver, *args, *reply.
                 // The args and reply must be structs until gobs are more general.
                 if mtype.NumIn() != 3 {
                         log.Stderr("method", mname, "has wrong number of ins:", mtype.NumIn());
                         continue;
                 }
                 argType, ok := mtype.In(1).(*reflect.PtrType);
                 if !ok {
-                        log.Stderr(mname, "arg type not a pointer:", argType.String());
+                        log.Stderr(mname, "arg type not a pointer:", mtype.In(1));
                         continue;
                 }
                 if _, ok := argType.Elem().(*reflect.StructType); !ok {
-                        log.Stderr(mname, "arg type not a pointer to a struct:", argType.String());
+                        log.Stderr(mname, "arg type not a pointer to a struct:", argType);
                         continue;
                 }
                 replyType, ok := mtype.In(2).(*reflect.PtrType);
                 if !ok {
-                        log.Stderr(mname, "reply type not a pointer:", replyType.String());
+                        log.Stderr(mname, "reply type not a pointer:", mtype.In(2));
                         continue;
                 }
                 if _, ok := replyType.Elem().(*reflect.StructType); !ok {
-                        log.Stderr(mname, "reply type not a pointer to a struct:", replyType.String());
+                        log.Stderr(mname, "reply type not a pointer to a struct:", replyType);
                         continue;
                 }
                 if !isPublic(argType.Elem().Name()) {
-                        log.Stderr(mname, "argument type not public:", argType.String());
+                        log.Stderr(mname, "argument type not public:", argType);
                         continue;
                 }
                 if !isPublic(replyType.Elem().Name()) {
-                        log.Stderr(mname, "reply type not public:", replyType.String());
+                        log.Stderr(mname, "reply type not public:", replyType);
                         continue;
                 }
                 // Method needs one out: os.Error.
                 if mtype.NumOut() != 1 {
                         log.Stderr("method", mname, "has wrong number of outs:", mtype.NumOut());
                         continue;
                 }
                 if returnType := mtype.Out(0); returnType != typeOfOsError {
                         log.Stderr("method", mname, "returns", returnType.String(), "not os.Error");
                         continue;
@@ skipping 155 matching lines @@
         io.WriteString(conn, "HTTP/1.0 "+connected+"\n\n");
         server.input(conn);
 }
 
 // HandleHTTP registers an HTTP handler for RPC messages.
 // It is still necessary to invoke http.Serve(), typically in a go statement.
 func HandleHTTP() {
         http.Handle(rpcPath, http.HandlerFunc(serveHTTP));
         http.Handle(debugPath, http.HandlerFunc(debugHTTP));
 }