Fix connecting via an already open QIODevice transportv5.11.0-beta4v5.11.0-beta3

In case a transport is handed over to QMqttClient which is based on
QIODevice and already opened, the implementation was not sending a
CONNECT request and hence the broker never got informed about a new
client establishing connection. Hence manually send the connect
statement.

For QAbstractSocket based transports this was done already.

Task-number: QTBUG-66955
Change-Id: I50cba1b6dd03d0af561d4e39a3b57af5b2161a4b
Reviewed-by: Oliver Wolff <oliver.wolff@qt.io>

2 files changed, 37 insertions, 1 deletions

diff --git a/src/mqtt/qmqttconnection.cpp b/src/mqtt/qmqttconnection.cpp
index aaaa514..b60816a 100644
--- a/src/mqtt/qmqttconnection.cpp
+++ b/src/mqtt/qmqttconnection.cpp
@@ -126,7 +126,7 @@ bool QMqttConnection::ensureTransportOpen(const QString &sslPeerName)
 
     if (m_transportType == QMqttClient::IODevice) {
         if (m_transport->isOpen())
-            return true;
+            return sendControlConnect();
 
         if (!m_transport->open(QIODevice::ReadWrite)) {
             qWarning("Could not open Transport IO device");
diff --git a/tests/auto/qmqttclient/tst_qmqttclient.cpp b/tests/auto/qmqttclient/tst_qmqttclient.cpp
index e6cf055..b94bfd4 100644
--- a/tests/auto/qmqttclient/tst_qmqttclient.cpp
+++ b/tests/auto/qmqttclient/tst_qmqttclient.cpp
@@ -57,6 +57,7 @@ private Q_SLOTS:
     void dataIncludingZero();
     void publishLongTopic();
     void reconnect_QTBUG65726();
+    void openIODevice_QTBUG66955();
 private:
     QProcess m_brokerProcess;
     QString m_testBroker;
@@ -447,6 +448,41 @@ void Tst_QMqttClient::reconnect_QTBUG65726()
     QTRY_COMPARE(client.error(), QMqttClient::NoError);
 }
 
+class IOTransport : public QIODevice
+{
+public:
+    bool open(OpenMode mode) override {
+        return QIODevice::open(mode);
+    }
+    qint64 readData(char *data, qint64 maxlen) override {
+        Q_UNUSED(data);
+        Q_UNUSED(maxlen);
+        return 0;
+    }
+    qint64 writeData(const char *data, qint64 len) override {
+        Q_UNUSED(data);
+        Q_UNUSED(len);
+        if (data[0] == 0x10)
+            written = 1;
+        else
+            qWarning() << "Received unknown/invalid data";
+        return len;
+    }
+    QAtomicInt written{0};
+};
+
+void Tst_QMqttClient::openIODevice_QTBUG66955()
+{
+    IOTransport trans;
+    trans.open(QIODevice::ReadWrite);
+
+    QMqttClient client;
+    client.setTransport(&trans, QMqttClient::IODevice);
+    client.connectToHost();
+
+    QTRY_COMPARE(trans.written, 1);
+}
+
 QTEST_MAIN(Tst_QMqttClient)
 
 #include "tst_qmqttclient.moc"