Improve warning messages (and readability) of connectSlotsByName()

While adding a test case for the new behavior, two issues
with the connectSlotsByName implementation came up:

  1. for auto-connected slots that don't exactly match a signal,
     a 'compatible' one is searched. There might be more than
     one of those. The implementation randomly picks any.
  2. The "No matching signal for %s" warning gets printed even for
     slots that can never be connected via connectSlotsMyName
     anyway (e.g. "on_something"). This is inconsistent.

This fixed both: an explicit warning is printed if more than one
'compatible' signal is found and the "No matching signal for %s"
warning is only printed if the slot adheres to the full
"on_child_signal()" naming convention.

In the process I added comments and changed the code slightly to
make it more readable and explicitly hint at non-obvious behavior.

Change-Id: Icc8e3b9936188d2da8dfff9f0373c8e5c776eb14
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/tests/auto/corelib/kernel/qobject/tst_qobject.cpp b/tests/auto/corelib/kernel/qobject/tst_qobject.cpp
index db21ab4fe4..dd88d863c9 100644
--- a/tests/auto/corelib/kernel/qobject/tst_qobject.cpp
+++ b/tests/auto/corelib/kernel/qobject/tst_qobject.cpp
@@ -427,6 +427,9 @@ public slots:
 protected slots:
     void o() { called_slots << -1; }
     void on() { called_slots << -1; }
+    void on_() { called_slots << -1; }
+    void on_something() { called_slots << -1; }
+    void on_child_signal() { called_slots << -1; }
 
 signals:
     void on_Sender_signalLoopBack();
@@ -441,6 +444,8 @@ void tst_QObject::connectSlotsByName()
     AutoConnectSender sender(&receiver);
     sender.setObjectName("Sender");
 
+    QTest::ignoreMessage(QtWarningMsg, "QMetaObject::connectSlotsByName: No matching signal for on_child_signal()");
+    QTest::ignoreMessage(QtWarningMsg, "QMetaObject::connectSlotsByName: Connecting slot on_Sender_signalManyParams() with the first of the following compatible signals: (\"signalManyParams(int,int,int,QString,bool)\", \"signalManyParams(int,int,int,QString,bool,bool)\") ");
     QMetaObject::connectSlotsByName(&receiver);
 
     receiver.called_slots.clear();