QByteArray: change append(QByteArray) to match QStringBuilder behavior

I.e. concatenating a null byte array and an empty-but-not-null byte
array should result in an empty-but-not-null byte array.

This matches the behavior of QString::append(QString) too.

Fixes: QTBUG-114238
Pick-to: 6.6
Change-Id: Id36d10ee09c08041b7dabda102df48ca6d413d8b
Reviewed-by: Thiago Macieira <[email protected]>

1 files changed, 8 insertions, 3 deletions

diff --git a/src/corelib/text/qbytearray.cpp b/src/corelib/text/qbytearray.cpp
index 7f8349131d8..42921e99d76 100644
--- a/src/corelib/text/qbytearray.cpp
+++ b/src/corelib/text/qbytearray.cpp
@@ -2044,9 +2044,14 @@ QByteArray &QByteArray::prepend(const QByteArray &ba)
 
 QByteArray &QByteArray::append(const QByteArray &ba)
 {
-    if (size() == 0 && ba.size() > d->freeSpaceAtEnd() && ba.d.isMutable())
-        return (*this = ba);
-    return append(QByteArrayView(ba));
+    if (!ba.isNull()) {
+        if (isNull()) {
+            operator=(ba);
+        } else if (ba.size()) {
+            append(QByteArrayView(ba));
+        }
+    }
+    return *this;
 }
 
 /*!