Fix multi-editing can lead to crash

src/core/featuremodel.cpp

@@ -533,16 +533,19 @@ bool FeatureModel::save()
 
  case MultiFeatureModel:
  {
- for ( QgsFeature &feature : mFeatures )
+ // We need to copy these members as the first feature updated triggers a refresh of the selected features, leading to changes in feature model members
+ const QgsFeature referenceFeature = mFeature;
+ const QList<bool> attributesAllowEdit = mAttributesAllowEdit;
+ QList<QgsFeature> features = mFeatures;
+ for ( QgsFeature &feature : features )
  {
- for ( int i = 0; i < mFeature.attributes().count(); i++ )
+ for ( int i = 0; i < referenceFeature.attributes().count(); i++ )
  {
- if ( !mAttributesAllowEdit[i] )
+ if ( !attributesAllowEdit[i] )
  continue;
 
- feature.setAttribute( i, mFeature.attributes().at( i ) );
+ feature.setAttribute( i, referenceFeature.attributes().at( i ) );
  }
-
  if ( !mLayer->updateFeature( feature ) )
  {
  QgsMessageLog::logMessage( tr( "Cannot update feature" ), QStringLiteral( "QField" ), Qgis::Warning );