client.go

@@ -1261,13 +1261,14 @@ func (c *Client) sendSingleMsg(message *Msg) error {
 			affectedMsg: message,
 		}
 	}
+	message.isDelivered = true
+
 	if err = writer.Close(); err != nil {
 		return &SendError{
 			Reason: ErrSMTPDataClose, errlist: []error{err}, isTemp: isTempError(err),
 			affectedMsg: message,
 		}
 	}
-	message.isDelivered = true
 
 	if err = c.Reset(); err != nil {
 		return &SendError{

client_test.go

@@ -3527,9 +3527,6 @@ func parseJSONLog(t *testing.T, buf *bytes.Buffer) logData {
 func testMessage(t *testing.T) *Msg {
 	t.Helper()
 	message := NewMsg()
-	if message == nil {
-		t.Fatal("failed to create new message")
-	}
 	if err := message.From(TestSenderValid); err != nil {
 		t.Errorf("failed to set sender address: %s", err)
 	}

msg.go

@@ -847,16 +847,7 @@ func (m *Msg) CcIgnoreInvalid(rcpts ...string) {
 // References:
 //   - https://datatracker.ietf.org/doc/html/rfc5322#section-3.6.3
 func (m *Msg) CcFromString(rcpts string) error {
-	src := strings.Split(rcpts, ",")
-	var dst []string
-	for _, address := range src {
-		address = strings.TrimSpace(address)
-		if address == "" {
-			continue
-		}
-		dst = append(dst, address)
-	}
-	return m.Cc(dst...)
+	return m.Cc(strings.Split(rcpts, ",")...)
 }
 
 // Bcc sets one or more "BCC" (blind carbon copy) addresses in the mail body for the Msg.
@@ -942,16 +933,7 @@ func (m *Msg) BccIgnoreInvalid(rcpts ...string) {
 // References:
 //   - https://datatracker.ietf.org/doc/html/rfc5322#section-3.6.3
 func (m *Msg) BccFromString(rcpts string) error {
-	src := strings.Split(rcpts, ",")
-	var dst []string
-	for _, address := range src {
-		address = strings.TrimSpace(address)
-		if address == "" {
-			continue
-		}
-		dst = append(dst, address)
-	}
-	return m.Bcc(dst...)
+	return m.Bcc(strings.Split(rcpts, ",")...)
 }
 
 // ReplyTo sets the "Reply-To" address for the Msg, specifying where replies should be sent.
@@ -1087,7 +1069,8 @@ func (m *Msg) SetBulk() {
 //   - https://datatracker.ietf.org/doc/html/rfc5322#section-3.3
 //   - https://datatracker.ietf.org/doc/html/rfc1123
 func (m *Msg) SetDate() {
-	m.SetDateWithValue(time.Now())
+	now := time.Now().Format(time.RFC1123Z)
+	m.SetGenHeader(HeaderDate, now)
 }
 
 // SetDateWithValue sets the "Date" header for the Msg using the provided time value in a valid RFC 1123 format.
@@ -1187,9 +1170,6 @@ func (m *Msg) IsDelivered() bool {
 // References:
 //   - https://datatracker.ietf.org/doc/html/rfc8098
 func (m *Msg) RequestMDNTo(rcpts ...string) error {
-	if m.genHeader == nil {
-		m.genHeader = make(map[Header][]string)
-	}
 	var addresses []string
 	for _, addrVal := range rcpts {
 		address, err := mail.ParseAddress(addrVal)
@@ -1198,7 +1178,9 @@ func (m *Msg) RequestMDNTo(rcpts ...string) error {
 		}
 		addresses = append(addresses, address.String())
 	}
-	m.genHeader[HeaderDispositionNotificationTo] = addresses
+	if _, ok := m.genHeader[HeaderDispositionNotificationTo]; ok {
+		m.genHeader[HeaderDispositionNotificationTo] = addresses
+	}
 	return nil
 }
 
@@ -1237,11 +1219,11 @@ func (m *Msg) RequestMDNAddTo(rcpt string) error {
 		return fmt.Errorf(errParseMailAddr, rcpt, err)
 	}
 	var addresses []string
-	if current, ok := m.genHeader[HeaderDispositionNotificationTo]; ok {
-		addresses = current
-	}
+	addresses = append(addresses, m.genHeader[HeaderDispositionNotificationTo]...)
 	addresses = append(addresses, address.String())
-	m.genHeader[HeaderDispositionNotificationTo] = addresses
+	if _, ok := m.genHeader[HeaderDispositionNotificationTo]; ok {
+		m.genHeader[HeaderDispositionNotificationTo] = addresses
+	}
 	return nil
 }