Skip Welcome mode when loading session or file at startup

Fixes: QTCREATORBUG-32321
Change-Id: I469437ab4b5dea917cdaff2341264f5eebf675e8
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>
Reviewed-by: hjk <hjk@qt.io>

src/plugins/coreplugin/session.cpp

@@ -409,6 +409,12 @@ static QString determineSessionToRestoreAtStartup()
     return {};
 }
 
+bool SessionManager::loadsSessionOrFileAtStartup()
+{
+    // "left-over arguments" usually mean a session or files
+    return !PluginManager::arguments().isEmpty() || !determineSessionToRestoreAtStartup().isEmpty();
+}
+
 void SessionManagerPrivate::restoreStartupSession()
 {
     NANOTRACE_SCOPE("Core", "SessionManagerPrivate::restoreStartupSession");

src/plugins/coreplugin/session.h

@@ -28,6 +28,8 @@ public:
 
     static SessionManager *instance();
 
+    static bool loadsSessionOrFileAtStartup();
+
     // higher level session management
     static QString activeSession();
     static QString lastSession();

src/plugins/welcome/welcomeplugin.cpp

@@ -16,6 +16,7 @@
 #include <coreplugin/imode.h>
 #include <coreplugin/iwelcomepage.h>
 #include <coreplugin/modemanager.h>
+#include <coreplugin/session.h>
 #include <coreplugin/welcomepagehelper.h>
 
 #include <utils/algorithm.h>
@@ -360,6 +361,7 @@ public:
     void extensionsInitialized()
     {
         m_modeWidget->initPlugins();
+        if (!SessionManager::loadsSessionOrFileAtStartup())
             ModeManager::activateMode(id());
     }