QDBusConnection: Print error from prepareHook

When the operation fails we print a warning, but that warning does not
include the error message that prepareHook internally collects but
ignores.

Printing the error is useful for debugging.

Pick-to: 6.6
Change-Id: I946c4781942115a17ffd43a79bff7676b6674be1
Reviewed-by: Thiago Macieira <[email protected]>

2 files changed, 25 insertions, 20 deletions

diff --git a/src/dbus/qdbusconnection_p.h b/src/dbus/qdbusconnection_p.h
index 1b79d3911ce..53e68748186 100644
--- a/src/dbus/qdbusconnection_p.h
+++ b/src/dbus/qdbusconnection_p.h
@@ -320,11 +320,10 @@ public:
     static int findSlot(QObject *obj, const QByteArray &normalizedName, QList<QMetaType> &params,
                         QString &errorMsg);
     static bool prepareHook(QDBusConnectionPrivate::SignalHook &hook, QString &key,
-                            const QString &service,
-                            const QString &path, const QString &interface, const QString &name,
-                            const ArgMatchRules &argMatch,
-                            QObject *receiver, const char *signal, int minMIdx,
-                            bool buildSignature);
+                            const QString &service, const QString &path, const QString &interface,
+                            const QString &name, const ArgMatchRules &argMatch, QObject *receiver,
+                            const char *signal, int minMIdx, bool buildSignature,
+                            QString &errorMsg);
     static QDBusCallDeliveryEvent *prepareReply(QDBusConnectionPrivate *target, QObject *object,
                                                 int idx, const QList<QMetaType> &metaTypes,
                                                 const QDBusMessage &msg);
diff --git a/src/dbus/qdbusintegrator.cpp b/src/dbus/qdbusintegrator.cpp
index c61ca27b5d1..276a3fcc3fb 100644
--- a/src/dbus/qdbusintegrator.cpp
+++ b/src/dbus/qdbusintegrator.cpp
@@ -1304,14 +1304,13 @@ int QDBusConnectionPrivate::findSlot(QObject *obj, const QByteArray &normalizedN
 }
 
 bool QDBusConnectionPrivate::prepareHook(QDBusConnectionPrivate::SignalHook &hook, QString &key,
-                                         const QString &service,
-                                         const QString &path, const QString &interface, const QString &name,
-                                         const ArgMatchRules &argMatch,
-                                         QObject *receiver, const char *signal, int minMIdx,
-                                         bool buildSignature)
+                                         const QString &service, const QString &path,
+                                         const QString &interface, const QString &name,
+                                         const ArgMatchRules &argMatch, QObject *receiver,
+                                         const char *signal, int minMIdx, bool buildSignature,
+                                         QString &errorMsg)
 {
     QByteArray normalizedName = signal + 1;
-    QString errorMsg;
     hook.midx = findSlot(receiver, signal + 1, hook.params, errorMsg);
     if (hook.midx == -1) {
         normalizedName = QMetaObject::normalizedSignature(signal + 1);
@@ -2225,9 +2224,11 @@ bool QDBusConnectionPrivate::connectSignal(const QString &service,
     QString key;
 
     hook.signature = signature;
+    QString errorMsg;
     if (!prepareHook(hook, key, service, path, interface, name, argumentMatch, receiver, slot, 0,
-                     false)) {
-        qCWarning(dbusIntegration) << "Could not connect" << interface << "to" << slot + 1;
+                     false, errorMsg)) {
+        qCWarning(dbusIntegration)
+                << "Could not connect" << interface << "to" << slot + 1 << ":" << qPrintable(errorMsg);
         return false;           // don't connect
     }
 
@@ -2328,9 +2329,11 @@ bool QDBusConnectionPrivate::disconnectSignal(const QString &service,
         name2.detach();
 
     hook.signature = signature;
+    QString errorMsg;
     if (!prepareHook(hook, key, service, path, interface, name, argumentMatch, receiver, slot, 0,
-                     false)) {
-        qCWarning(dbusIntegration) << "Could not disconnect" << interface << "to" << slot + 1;
+                     false, errorMsg)) {
+        qCWarning(dbusIntegration)
+                << "Could not disconnect" << interface << "to" << slot + 1 << ":" << qPrintable(errorMsg);
         return false;           // don't disconnect
     }
 
@@ -2470,9 +2473,11 @@ void QDBusConnectionPrivate::connectRelay(const QString &service,
     QByteArray sig;
     sig.append(QSIGNAL_CODE + '0');
     sig.append(signal.methodSignature());
+    QString errorMsg;
     if (!prepareHook(hook, key, service, path, interface, QString(), ArgMatchRules(), receiver, sig,
-                     QDBusAbstractInterface::staticMetaObject.methodCount(), true)) {
-        qCWarning(dbusIntegration) << "Could not connect" << interface << "to" << signal.name();
+                     QDBusAbstractInterface::staticMetaObject.methodCount(), true, errorMsg)) {
+        qCWarning(dbusIntegration)
+                << "Could not connect" << interface << "to" << signal.name() << ":" << qPrintable(errorMsg);
         return;                 // don't connect
     }
 
@@ -2493,10 +2498,11 @@ void QDBusConnectionPrivate::disconnectRelay(const QString &service,
     QByteArray sig;
     sig.append(QSIGNAL_CODE + '0');
     sig.append(signal.methodSignature());
+    QString errorMsg;
     if (!prepareHook(hook, key, service, path, interface, QString(), ArgMatchRules(), receiver, sig,
-                     QDBusAbstractInterface::staticMetaObject.methodCount(), true)) {
-        qCWarning(dbusIntegration)
-                << "Could not disconnect" << interface << "to" << signal.methodSignature();
+                     QDBusAbstractInterface::staticMetaObject.methodCount(), true, errorMsg)) {
+        qCWarning(dbusIntegration) << "Could not disconnect" << interface << "to"
+                                   << signal.methodSignature() << ":" << qPrintable(errorMsg);
         return;                 // don't disconnect
     }