From 5615f60bb05d687df842f002ffb8c2ebb063d50b Mon Sep 17 00:00:00 2001
From: Blake Mizerany <blake.mizerany@gmail.com>
Date: Sat, 6 Apr 2024 21:56:28 -0700
Subject: [PATCH] x/model: more comments on UnmarshalText and immutability

---
 x/model/name.go | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/x/model/name.go b/x/model/name.go
index 0319c7ea6..1a4fa4d42 100644
--- a/x/model/name.go
+++ b/x/model/name.go
@@ -320,6 +320,10 @@ func (r Name) MarshalText() ([]byte, error) {
 // It is an error to call UnmarshalText on a valid Name.
 func (r *Name) UnmarshalText(text []byte) error {
 	if r.Valid() {
+		// The invariant of UnmarshalText is that it should only be
+		// called on an invalid/zero Name. If we allow UnmarshalText
+		// on a valid Name, then the Name will be mutated, breaking
+		// the immutability of the Name.
 		return errors.New("model.Name: UnmarshalText on valid Name")
 	}
 	// unsafeString is safe here because the contract of UnmarshalText