From 061c065cc1eef1b039f09076f4eb7cc612f45234 Mon Sep 17 00:00:00 2001
From: willem <itsme@xs4all.nl>
Date: Tue, 17 Sep 2024 11:39:58 +0200
Subject: [PATCH] binary: fix encoding attribute count when there are empty
 values (#658)

Co-authored-by: Tulir Asokan <tulir@maunium.net>
---
 binary/encoder.go | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/binary/encoder.go b/binary/encoder.go
index 21e22cf8..eed07184 100644
--- a/binary/encoder.go
+++ b/binary/encoder.go
@@ -90,7 +90,7 @@ func (w *binaryEncoder) writeNode(n Node) {
 		hasContent = 1
 	}
 
-	w.writeListStart(2*len(n.Attrs) + tagSize + hasContent)
+	w.writeListStart(2*w.countAttributes(n.Attrs) + tagSize + hasContent)
 	w.writeString(n.Tag)
 	w.writeAttributes(n.Attrs)
 	if n.Content != nil {
@@ -187,10 +187,6 @@ func (w *binaryEncoder) writeJID(jid types.JID) {
 }
 
 func (w *binaryEncoder) writeAttributes(attributes Attrs) {
-	if attributes == nil {
-		return
-	}
-
 	for key, val := range attributes {
 		if val == "" || val == nil {
 			continue
@@ -201,6 +197,16 @@ func (w *binaryEncoder) writeAttributes(attributes Attrs) {
 	}
 }
 
+func (w *binaryEncoder) countAttributes(attributes Attrs) (count int) {
+	for _, val := range attributes {
+		if val == "" || val == nil {
+			continue
+		}
+		count += 1
+	}
+	return
+}
+
 func (w *binaryEncoder) writeListStart(listSize int) {
 	if listSize == 0 {
 		w.pushByte(byte(token.ListEmpty))