Panic when registering the same type but diff urls

Panic on typeurl registration when you register the same type but
different urls for that type.

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

typeurl/types.go

@@ -22,13 +22,19 @@ var (
 
 // Register a type with the base url of the type
 func Register(v interface{}, args ...string) {
-	t := tryDereference(v)
+	var (
+		t = tryDereference(v)
+		p = path.Join(append([]string{Prefix}, args...)...)
+	)
 	mu.Lock()
 	defer mu.Unlock()
-	if _, ok := registry[t]; ok {
+	if et, ok := registry[t]; ok {
+		if et != p {
+			panic(errors.Errorf("type registred with alternate path %q != %q", et, p))
+		}
 		return
 	}
-	registry[t] = path.Join(append([]string{Prefix}, args...)...)
+	registry[t] = p
 }
 
 // TypeURL returns the type url for a registred type

typeurl/types_test.go

@@ -130,6 +130,17 @@ func TestMarshalEvent(t *testing.T) {
 	}
 }
 
+func TestRegisterDiffUrls(t *testing.T) {
+	clear()
+	defer func() {
+		if err := recover(); err == nil {
+			t.Error("registering the same type with different urls should panic")
+		}
+	}()
+	Register(&test{}, "test")
+	Register(&test{}, "test", "two")
+}
+
 func BenchmarkMarshalEvent(b *testing.B) {
 	ev := &eventsapi.TaskStart{}
 	expected, err := MarshalAny(ev)