debugger: fix 'Detach debugger' action

src/plugins/debugger/debuggermanager.cpp

@@ -1695,8 +1695,6 @@ void DebuggerManager::setState(DebuggerState state)
     d->m_actions.runToFunctionAction->setEnabled(stopped);
     d->m_actions.jumpToLineAction->setEnabled(stopped);
     d->m_actions.nextAction->setEnabled(stopped);
-    //showStatusMessage(QString("stoppable: %1, running: %2")
-    // .arg(stoppable).arg(running));
     emit stateChanged(d->m_state);
     const bool notbusy = state == InferiorStopped
         || state == DebuggerNotReady

src/plugins/debugger/debuggerplugin.cpp

@@ -898,6 +898,7 @@ bool DebuggerPlugin::initialize(const QStringList &arguments, QString *errorMess
     connect(theDebuggerAction(SettingsDialog), SIGNAL(triggered()),
         this, SLOT(showSettingsDialog()));
 
+    handleStateChanged(DebuggerNotReady);
     return true;
 }
 
@@ -1120,8 +1121,8 @@ void DebuggerPlugin::handleStateChanged(int state)
     const bool starting = state == EngineStarting;
     //const bool running = state == InferiorRunning;
 
-    const bool ready = state == InferiorStopped
-            && m_manager->startParameters()->startMode != AttachCore;
+    const bool detachable = state == InferiorStopped
+        && m_manager->startParameters()->startMode != AttachCore;
 
     m_startExternalAction->setEnabled(!started && !starting);
     m_attachExternalAction->setEnabled(!started && !starting);
@@ -1131,7 +1132,7 @@ void DebuggerPlugin::handleStateChanged(int state)
     m_attachCoreAction->setEnabled(!started && !starting);
 #endif
     m_startRemoteAction->setEnabled(!started && !starting);
-    m_detachAction->setEnabled(ready);
+    m_detachAction->setEnabled(detachable);
 }
 
 void DebuggerPlugin::writeSettings() const

src/plugins/debugger/gdb/gdbengine.cpp

@@ -1444,7 +1444,11 @@ void GdbEngine::shutdown()
 
 void GdbEngine::detachDebugger()
 {
-    QTC_ASSERT(startMode() == AttachExternal, /**/);
+    QTC_ASSERT(state() == InferiorStopped, /**/);
+    QTC_ASSERT(startMode() != AttachCore, /**/);
+    postCommand(_("detach")); 
+    setState(InferiorShuttingDown);
+    setState(InferiorShutDown);
     shutdown();
 }