address: Special-case null return-path in normalization functions

See #629.
foxcpp · Feb 8, 2024 · cee5777 · cee5777
1 parent 4a69c9e
commit cee5777
Showing 1 changed file with 8 additions and 0 deletions.
diff --git a/framework/address/norm.go b/framework/address/norm.go
@@ -36,6 +36,10 @@ import (
 //
 // On error, case-folded addr is also returned.
 func ForLookup(addr string) (string, error) {
+	if addr == "" { // Null return-path case.
+		return "", nil
+	}
+
 	mbox, domain, err := Split(addr)
 	if err != nil {
 		return strings.ToLower(addr), err
@@ -64,6 +68,10 @@ func ForLookup(addr string) (string, error) {
 //
 // Original value is also returned on the error.
 func CleanDomain(addr string) (string, error) {
+	if addr == "" { // Null return-path
+		return "", nil
+	}
+
 	mbox, domain, err := Split(addr)
 	if err != nil {
 		return addr, err