Keep attributes when adding 1-N related features with a multi-edition attribute form

python/PyQt6/core/auto_generated/vector/qgsvectorlayertoolscontext.sip.in

@@ -99,6 +99,15 @@ Returns whether the parent widget should be hidden when showing tools' dialogues
     void setHideParent( bool hide );
 %Docstring
 Sets whether the parent widget should be hidden when showing tools' dialogues.
+%End
+
+    bool forceSuppressFormPopup() const;
+%Docstring
+Returns whether the add feature form popup should be shown
+%End
+    void setForceSuppressFormPopup( bool forceSuppressFormPopup );
+%Docstring
+Sets whether the add feature form popup should be shown
 %End
 
 };

python/core/auto_generated/vector/qgsvectorlayertoolscontext.sip.in

@@ -99,6 +99,15 @@ Returns whether the parent widget should be hidden when showing tools' dialogues
     void setHideParent( bool hide );
 %Docstring
 Sets whether the parent widget should be hidden when showing tools' dialogues.
+%End
+
+    bool forceSuppressFormPopup() const;
+%Docstring
+Returns whether the add feature form popup should be shown
+%End
+    void setForceSuppressFormPopup( bool forceSuppressFormPopup );
+%Docstring
+Sets whether the add feature form popup should be shown
 %End
 
 };

src/app/qgsguivectorlayertools.cpp

@@ -37,6 +37,11 @@ bool QgsGuiVectorLayerTools::addFeatureV2( QgsVectorLayer *layer, const QgsAttri
   f->setGeometry( defaultGeometry );
   QgsFeatureAction *a = new QgsFeatureAction( tr( "Add feature" ), *f, layer, QUuid(), -1, context.parentWidget() );
   a->setForceSuppressFormPopup( forceSuppressFormPopup() );
+
+  // Override with context
+  if ( context.forceSuppressFormPopup() )
+    a->setForceSuppressFormPopup( true );
+
   connect( a, &QgsFeatureAction::addFeatureFinished, a, &QObject::deleteLater );
   const QgsFeatureAction::AddFeatureResult result = a->addFeature( defaultValues, context.showModal(), std::unique_ptr<QgsExpressionContextScope>( context.additionalExpressionContextScope() ? new QgsExpressionContextScope( *context.additionalExpressionContextScope() ) : nullptr ), context.hideParent() );
   if ( !feature )

src/core/vector/qgsvectorlayertoolscontext.h

@@ -101,6 +101,16 @@ class CORE_EXPORT QgsVectorLayerToolsContext
      */
     void setHideParent( bool hide ) { mHideParent = hide; }
 
+    /**
+     * Returns whether the add feature form popup should be shown
+     */
+    bool forceSuppressFormPopup() const { return mForceSuppressFormPopup; };
+
+    /**
+     * Sets whether the add feature form popup should be shown
+     */
+    void setForceSuppressFormPopup( bool forceSuppressFormPopup ) { mForceSuppressFormPopup = forceSuppressFormPopup; }
+
   private:
 
     std::unique_ptr< QgsExpressionContext > mExpressionContext;
@@ -109,6 +119,7 @@ class CORE_EXPORT QgsVectorLayerToolsContext
     QWidget *mParentWidget = nullptr;
     bool mShowModal = true;
     bool mHideParent = false;
+    bool mForceSuppressFormPopup = false;
 };
 
 #endif // QGSVECTORLAYERTOOLSCONTEXT_H

src/gui/qgsabstractrelationeditorwidget.cpp

@@ -29,6 +29,8 @@
 #include "qgsproject.h"
 #include "qgstransactiongroup.h"
 #include "qgsvectorlayerutils.h"
+#include "qgssettingsregistrycore.h"
+#include "qgssettingsentryimpl.h"
 
 #include <QMessageBox>
 #include <QPushButton>
@@ -283,35 +285,34 @@ QgsFeatureIds QgsAbstractRelationEditorWidget::addFeature( const QgsGeometry &ge
   }
   else
   {
-    const auto constFieldPairs = mRelation.fieldPairs();
-    for ( const QgsRelation::FieldPair &fieldPair : constFieldPairs )
-      keyAttrs.insert( fields.indexFromName( fieldPair.referencingField() ), mFeatureList.first().attribute( fieldPair.referencedField() ) );
-
+    const bool prevReuseAllLastValues = QgsSettingsRegistryCore::settingsDigitizingReuseLastValues->value();
     QgsVectorLayerToolsContext context;
     context.setParentWidget( this );
     context.setShowModal( false );
     context.setHideParent( true );
-    std::unique_ptr<QgsExpressionContextScope> scope( QgsExpressionContextUtils::parentFormScope( mFeatureList.first(), mEditorContext.attributeFormModeString() ) );
-    context.setAdditionalExpressionContextScope( scope.get() );
-    QgsFeature linkFeature;
-    if ( !vlTools->addFeatureV2( mRelation.referencingLayer(), keyAttrs, geometry, &linkFeature, context ) )
-      return QgsFeatureIds();
-
-    addedFeatureIds.insert( linkFeature.id() );
-
-    // In multiedit add to other features to but without dialog
-    for ( const QgsFeature &feature : std::as_const( mFeatureList ) )
+    for ( const QgsFeature &editingFeature : std::as_const( mFeatureList ) )
     {
-      // First feature already added
-      if ( mFeatureList.first() == feature )
-        continue;
-
+      const auto constFieldPairs = mRelation.fieldPairs();
       for ( const QgsRelation::FieldPair &fieldPair : constFieldPairs )
-        linkFeature.setAttribute( fields.indexFromName( fieldPair.referencingField() ), feature.attribute( fieldPair.referencedField() ) );
+        keyAttrs.insert( fields.indexFromName( fieldPair.referencingField() ), editingFeature.attribute( fieldPair.referencedField() ) );
 
-      mRelation.referencingLayer()->addFeature( linkFeature );
+      // In multiedit add to other features too but without dialog
+      if ( editingFeature != mFeatureList.first() )
+      {
+        QgsSettingsRegistryCore::settingsDigitizingReuseLastValues->setValue( true );
+        context.setForceSuppressFormPopup( true );
+      }
+      std::unique_ptr<QgsExpressionContextScope> scope( QgsExpressionContextUtils::parentFormScope( editingFeature, mEditorContext.attributeFormModeString() ) );
+      context.setAdditionalExpressionContextScope( scope.get() );
+      QgsFeature linkFeature;
+      if ( !vlTools->addFeatureV2( mRelation.referencingLayer(), keyAttrs, geometry, &linkFeature, context ) )
+      {
+        QgsSettingsRegistryCore::settingsDigitizingReuseLastValues->setValue( prevReuseAllLastValues );
+        return QgsFeatureIds();
+      }
       addedFeatureIds.insert( linkFeature.id() );
     }
+    QgsSettingsRegistryCore::settingsDigitizingReuseLastValues->setValue( prevReuseAllLastValues );
   }
 
   updateUi();