Make tst_qsslsocket::protocolServerSide() less flaky

By accident, when we erroneously tried testing TlsV1_3 on macOS with
SecureTransport (which does not support TLS 1.3) we hit this quite
subtle problem: it can happen that a server-side socket is never
created but a client (after TCP connection was established) fails
in TLS initialization and ... stops the loop preventing
SslServer::incomingConnection() from creating its socket. Then we
dereference nullptr.

Task-number: QTBUG-71638
Change-Id: I8dc5a4c53022a25aafe2c80a6931087517a48441
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>

1 files changed, 10 insertions, 4 deletions

diff --git a/tests/auto/network/ssl/qsslsocket/tst_qsslsocket.cpp b/tests/auto/network/ssl/qsslsocket/tst_qsslsocket.cpp
index b759aed074..f45a5af5a1 100644
--- a/tests/auto/network/ssl/qsslsocket/tst_qsslsocket.cpp
+++ b/tests/auto/network/ssl/qsslsocket/tst_qsslsocket.cpp
@@ -1343,13 +1343,19 @@ void tst_QSslSocket::protocolServerSide()
     QAbstractSocket::SocketState expectedState = (works) ? QAbstractSocket::ConnectedState : QAbstractSocket::UnconnectedState;
     // Determine whether the client or the server caused the event loop
     // to quit due to a socket error, and investigate the culprit.
-    if (server.socket->error() != QAbstractSocket::UnknownSocketError) {
+    if (client.error() != QAbstractSocket::UnknownSocketError) {
+        // It can happen that the client, after TCP connection established, before
+        // incomingConnection() slot fired, hits TLS initialization error and stops
+        // the loop, so the server socket is not created yet.
+        if (server.socket)
+            QVERIFY(server.socket->error() == QAbstractSocket::UnknownSocketError);
+
+        QCOMPARE(int(client.state()), int(expectedState));
+    } else if (server.socket->error() != QAbstractSocket::UnknownSocketError) {
         QVERIFY(client.error() == QAbstractSocket::UnknownSocketError);
         QCOMPARE(int(server.socket->state()), int(expectedState));
-    } else if (client.error() != QAbstractSocket::UnknownSocketError) {
-        QVERIFY(server.socket->error() == QAbstractSocket::UnknownSocketError);
-        QCOMPARE(int(client.state()), int(expectedState));
     }
+
     QCOMPARE(client.isEncrypted(), works);
 }