audit: codec/types: AnyUnpacker unnecessary creates a reflect.Value, boxes it then casts its to an interface just to see if it implements proto.Message, but could really just check if the original type implements the interface

[odeke-em]

Summary of Bug

Noticed while auditing changes between v0.47.0 and the latest that the code in question in cases that don't matter creates an unnecessary reflect.Value, boxes its zero value to an interface then performs a type assertion to see if it implements proto.Message

Version

3d15233

Suggestion

We can simply check against the original type that it implements proto.Message like this

diff --git a/codec/types/interface_registry.go b/codec/types/interface_registry.go
index 50a5ca01c..c8b18f08d 100644
--- a/codec/types/interface_registry.go
+++ b/codec/types/interface_registry.go
@@ -12,6 +12,8 @@ import (
        "cosmossdk.io/x/tx/signing"
 )
 
+var protoMessageType = reflect.TypeOf((*proto.Message)(nil)).Elem()
+
 // AnyUnpacker is an interface which allows safely unpacking types packed
 // in Any's against a whitelist of registered types
 type AnyUnpacker interface {
@@ -305,11 +307,13 @@ func (registry *interfaceRegistry) UnpackAny(any *Any, iface interface{}) error
                return fmt.Errorf("no concrete type registered for type URL %s against interface %T", any.TypeUrl, iface)
        }
 
-       msg, ok := reflect.New(typ.Elem()).Interface().(proto.Message)
-       if !ok {
-               return fmt.Errorf("can't proto unmarshal %T", msg)
+       // Firstly check if the type implements proto.Message to avoid
+        // unnecessary invocations to reflect.New
+       if !typ.Implements(protoMessageType) {
+               return fmt.Errorf("can't proto unmarshal %T", typ)
        }
 
+       msg := reflect.New(typ.Elem()).Interface().(proto.Message)
        err := proto.Unmarshal(any.Value, msg)
        if err != nil {
                return err

/cc @ elias-orijtech