2 files changed, 26 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;
 }
 
 /*!
diff --git a/tests/auto/corelib/text/qbytearray/tst_qbytearray.cpp b/tests/auto/corelib/text/qbytearray/tst_qbytearray.cpp
index bc84e256514..f5e149836ab 100644
--- a/tests/auto/corelib/text/qbytearray/tst_qbytearray.cpp
+++ b/tests/auto/corelib/text/qbytearray/tst_qbytearray.cpp
@@ -53,6 +53,7 @@ private slots:
     void append();
     void appendExtended_data();
     void appendExtended();
+    void appendEmptyNull();
     void assign();
     void assignShared();
     void assignUsesPrependBuffer();
@@ -937,6 +938,23 @@ void tst_QByteArray::appendExtended()
     QCOMPARE(array.size(), 11);
 }
 
+void tst_QByteArray::appendEmptyNull()
+{
+    QByteArray a;
+    QVERIFY(a.isEmpty());
+    QVERIFY(a.isNull());
+
+    QByteArray b("");
+    QVERIFY(b.isEmpty());
+    QVERIFY(!b.isNull());
+
+    // Concatenating a null and an empty-but-not-null byte arrays results in
+    // an empty but not null byte array
+    QByteArray r = a + b;
+    QVERIFY(r.isEmpty());
+    QVERIFY(!r.isNull());
+}
+
 void tst_QByteArray::assign()
 {
     // QByteArray &assign(QByteArrayView)