Fix crash caused by NULL vehicle

src/FactSystem/ParameterManager.cc

@@ -1177,7 +1177,7 @@ void ParameterManager::_initialRequestTimeout(void)
 QString ParameterManager::parameterMetaDataFile(Vehicle* vehicle, MAV_AUTOPILOT firmwareType, int wantedMajorVersion, int& majorVersion, int& minorVersion)
 {
     bool            cacheHit = false;
-    FirmwarePlugin* plugin = vehicle->firmwarePlugin();
+    FirmwarePlugin* plugin = _anyVehicleTypeFirmwarePlugin(firmwareType);
 
     // Cached files are stored in settings location
     QSettings settings;
@@ -1270,14 +1270,17 @@ QString ParameterManager::parameterMetaDataFile(Vehicle* vehicle, MAV_AUTOPILOT
     return metaDataFile;
 }
 
-void ParameterManager::cacheMetaDataFile(const QString& metaDataFile, MAV_AUTOPILOT firmwareType)
+FirmwarePlugin* ParameterManager::_anyVehicleTypeFirmwarePlugin(MAV_AUTOPILOT firmwareType)
 {
-    // In order to call FirmwarePlugin::getParameterMetaDataVersionInfo we need the firmware plugin. But at this point we do not have a vehicle associated
-    // with the call. Since the call to FirmwarePlugin::getParameterMetaDataVersionInfo is invariant to vehicle type we just need to use any one of the
-    // supported vehicle types to get the correct FirmwarePlugin.
+    // There are cases where we need a FirmwarePlugin but we don't have a vehicle. In those specified case the plugin for any of the supported vehicle types will do.
     MAV_TYPE anySupportedVehicleType = qgcApp()->toolbox()->firmwarePluginManager()->supportedVehicleTypes(firmwareType)[0];
 
-    FirmwarePlugin* plugin = qgcApp()->toolbox()->firmwarePluginManager()->firmwarePluginForAutopilot(firmwareType, anySupportedVehicleType);
+    return qgcApp()->toolbox()->firmwarePluginManager()->firmwarePluginForAutopilot(firmwareType, anySupportedVehicleType);
+}
+
+void ParameterManager::cacheMetaDataFile(const QString& metaDataFile, MAV_AUTOPILOT firmwareType)
+{
+    FirmwarePlugin* plugin = _anyVehicleTypeFirmwarePlugin(firmwareType);
 
     int newMajorVersion, newMinorVersion;
     plugin->getParameterMetaDataVersionInfo(metaDataFile, newMajorVersion, newMinorVersion);

src/FactSystem/ParameterManager.h

@@ -130,6 +130,8 @@ protected:
 
 private:
     static QVariant         _stringToTypedVariant(const QString& string, FactMetaData::ValueType_t type, bool failOk = false);
+    static FirmwarePlugin*  _anyVehicleTypeFirmwarePlugin(MAV_AUTOPILOT firmwareType);
+
     int     _actualComponentId(int componentId);
     void    _setupDefaultComponentCategoryMap(void);
     void    _readParameterRaw(int componentId, const QString& paramName, int paramIndex);