QDBus: improve error handling, to give the developer feedback.

For instance, exporting an object with a slot like
   QString complexMethod(const MyVariantMap& vars);
   (even with a simple typedef QVariantMap MyVariantMap)
used to silently skip that method in the introspection.
Now it outputs:
 generateInterfaceXml: Skipped method "complexMethod" : Invalid type in parameter list: MyVariantMap

Change-Id: I7964cfb63e973257ce1abe47b9625e361b2ad23f
Reviewed-by: Kevin Ottens <kevin.ottens@kdab.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

1 files changed, 7 insertions, 4 deletions

diff --git a/src/dbus/qdbusabstractadaptor.cpp b/src/dbus/qdbusabstractadaptor.cpp
index e08714f04d..1dbc79d6ec 100644
--- a/src/dbus/qdbusabstractadaptor.cpp
+++ b/src/dbus/qdbusabstractadaptor.cpp
@@ -298,15 +298,18 @@ void QDBusAdaptorConnector::relay(QObject *senderObj, int lastSignalIdx, void **
 
     // break down the parameter list
     QVector<int> types;
-    int inputCount = qDBusParametersForMethod(mm, types);
-    if (inputCount == -1)
+    QString errorMsg;
+    int inputCount = qDBusParametersForMethod(mm, types, errorMsg);
+    if (inputCount == -1) {
         // invalid signal signature
-        // qDBusParametersForMethod has already complained
+        qWarning("QDBusAbstractAdaptor: Cannot relay signal %s::%s: %s",
+                 senderMetaObject->className(), mm.methodSignature().constData(),
+                 qPrintable(errorMsg));
         return;
+    }
     if (inputCount + 1 != types.count() ||
         types.at(inputCount) == QDBusMetaTypeId::message()) {
         // invalid signal signature
-        // qDBusParametersForMethod has not yet complained about this one
         qWarning("QDBusAbstractAdaptor: Cannot relay signal %s::%s",
                  senderMetaObject->className(), mm.methodSignature().constData());
         return;