LanguageClient: track clients scheduled for deletion

So report an async shutdown if we have clients scheduled for deletion
and wait until all clients have been fully deleted.

Change-Id: I40d35d3429003ab2a5c68cb81486c3e16b5f6f63
Reviewed-by: Christian Stenger <christian.stenger@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>

src/plugins/languageclient/languageclientmanager.cpp

@@ -189,7 +189,7 @@ void LanguageClientManager::clientFinished(Client *client)
         }
     }
     deleteClient(client);
-    if (PluginManager::isShuttingDown() && managerInstance->m_clients.isEmpty())
+    if (isShutdownFinished())
         emit managerInstance->shutdownFinished();
 }
 
@@ -243,6 +243,7 @@ void LanguageClientManager::deleteClient(Client *client)
     // that will not handle the delete later event. Use invokeMethod with Qt::QueuedConnection
     // instead.
     QMetaObject::invokeMethod(client, [client] {delete client;}, Qt::QueuedConnection);
+    managerInstance->trackClientDeletion(client);
 
     if (!PluginManager::isShuttingDown())
         emit instance()->clientRemoved(client);
@@ -608,4 +609,24 @@ void LanguageClientManager::projectAdded(ProjectExplorer::Project *project)
         client->projectOpened(project);
 }
 
+void LanguageClientManager::trackClientDeletion(Client *client)
+{
+    QTC_ASSERT(!m_scheduledForDeletion.contains(client->id()), return);
+    m_scheduledForDeletion.insert(client->id());
+    connect(client, &QObject::destroyed, [this, id = client->id()](){
+        m_scheduledForDeletion.remove(id);
+        if (isShutdownFinished())
+            emit shutdownFinished();
+    });
+}
+
+bool LanguageClientManager::isShutdownFinished()
+{
+    if (!PluginManager::isShuttingDown())
+        return false;
+    QTC_ASSERT(managerInstance, return true);
+    return managerInstance->m_clients.isEmpty()
+           && managerInstance->m_scheduledForDeletion.isEmpty();
+}
+
 } // namespace LanguageClient

src/plugins/languageclient/languageclientmanager.h

@@ -48,6 +48,7 @@ public:
     static void deleteClient(Client *client);
 
     static void shutdown();
+    static bool isShutdownFinished();
 
     static LanguageClientManager *instance();
 
@@ -96,6 +97,8 @@ private:
     void updateProject(ProjectExplorer::Project *project);
     void projectAdded(ProjectExplorer::Project *project);
 
+    void trackClientDeletion(Client *client);
+
     QList<Client *> reachableClients();
 
     QList<Client *> m_clients;
@@ -105,6 +108,7 @@ private:
     QHash<TextEditor::TextDocument *, QPointer<Client>> m_clientForDocument;
     std::unique_ptr<LanguageClientManagerPrivate> d;
     LspInspector m_inspector;
+    QSet<Utils::Id> m_scheduledForDeletion;
 };
 
 template<typename T> bool LanguageClientManager::hasClients()

src/plugins/languageclient/languageclientplugin.cpp

@@ -60,12 +60,12 @@ void LanguageClientPlugin::extensionsInitialized()
 ExtensionSystem::IPlugin::ShutdownFlag LanguageClientPlugin::aboutToShutdown()
 {
     LanguageClientManager::shutdown();
-    if (LanguageClientManager::clients().isEmpty())
+    if (LanguageClientManager::isShutdownFinished())
         return ExtensionSystem::IPlugin::SynchronousShutdown;
     QTC_ASSERT(LanguageClientManager::instance(),
                return ExtensionSystem::IPlugin::SynchronousShutdown);
     connect(LanguageClientManager::instance(), &LanguageClientManager::shutdownFinished,
-            this, &ExtensionSystem::IPlugin::asynchronousShutdownFinished, Qt::QueuedConnection);
+            this, &ExtensionSystem::IPlugin::asynchronousShutdownFinished);
     return ExtensionSystem::IPlugin::AsynchronousShutdown;
 }