Bugfix: avoid spurious tautology pruning when dealing with certain re…

…cursive messages (#142)

internal/evaluator/builder.go

@@ -83,7 +83,7 @@ func (bldr *Builder) load(desc protoreflect.MessageDescriptor) MessageEvaluator
 }
 
 // loadOrBuild either returns a memoized MessageEvaluator for the given
-// descriptor, or lazily constructs a new one. This method is thread-safe via
+// descriptor or lazily constructs a new one. This method is thread-safe via
 // locking.
 func (bldr *Builder) loadOrBuild(desc protoreflect.MessageDescriptor) MessageEvaluator {
 	if eval, ok := (*bldr.cache.Load())[desc]; ok {

internal/evaluator/message.go

@@ -41,7 +41,12 @@ func (m *message) EvaluateMessage(msg protoreflect.Message, failFast bool) error
 }
 
 func (m *message) Tautology() bool {
-	return m.Err == nil && m.evaluators.Tautology()
+	// returning false for now to avoid recursive messages causing false positives
+	// on tautology detection.
+	//
+	// TODO: use a more sophisticated method to detect recursions so we can
+	//  continue to detect tautologies on message evaluators.
+	return false
 }
 
 func (m *message) Append(eval MessageEvaluator) {