Merge pull request #42550 from 3nids/bp318

QgsAbstractRelationEditor fixes

src/gui/qgsabstractrelationeditorwidget.cpp

@@ -213,6 +213,16 @@ void QgsAbstractRelationEditorWidget::addFeature( const QgsGeometry &geometry )
 
   const QgsVectorLayerTools *vlTools = mEditorContext.vectorLayerTools();
 
+  // Fields of the linking table
+  const QgsFields fields = mRelation.referencingLayer()->fields();
+
+  // For generated relations insert the referenced layer field
+  if ( mRelation.type() == QgsRelation::Generated )
+  {
+    QgsPolymorphicRelation polyRel = mRelation.polymorphicRelation();
+    keyAttrs.insert( fields.indexFromName( polyRel.referencedLayerField() ), polyRel.layerRepresentation( mRelation.referencedLayer() ) );
+  }
+
   if ( mNmRelation.isValid() )
   {
     // only normal relations support m:n relation
@@ -221,52 +231,43 @@ void QgsAbstractRelationEditorWidget::addFeature( const QgsGeometry &geometry )
     // n:m Relation: first let the user create a new feature on the other table
     // and autocreate a new linking feature.
     QgsFeature f;
-    if ( vlTools->addFeature( mNmRelation.referencedLayer(), QgsAttributeMap(), geometry, &f ) )
-    {
-      // Fields of the linking table
-      const QgsFields fields = mRelation.referencingLayer()->fields();
-
-      // Expression context for the linking table
-      QgsExpressionContext context = mRelation.referencingLayer()->createExpressionContext();
-
-      QgsAttributeMap linkAttributes;
-      const auto constFieldPairs = mRelation.fieldPairs();
-      for ( const QgsRelation::FieldPair &fieldPair : constFieldPairs )
-      {
-        int index = fields.indexOf( fieldPair.first );
-        linkAttributes.insert( index,  mFeature.attribute( fieldPair.second ) );
-      }
+    if ( !vlTools->addFeature( mNmRelation.referencedLayer(), QgsAttributeMap(), geometry, &f ) )
+      return;
 
-      const auto constNmFieldPairs = mNmRelation.fieldPairs();
-      for ( const QgsRelation::FieldPair &fieldPair : constNmFieldPairs )
-      {
-        int index = fields.indexOf( fieldPair.first );
-        linkAttributes.insert( index, f.attribute( fieldPair.second ) );
-      }
-      QgsFeature linkFeature = QgsVectorLayerUtils::createFeature( mRelation.referencingLayer(), QgsGeometry(), linkAttributes, &context );
+    // Expression context for the linking table
+    QgsExpressionContext context = mRelation.referencingLayer()->createExpressionContext();
 
-      mRelation.referencingLayer()->addFeature( linkFeature );
+    QgsAttributeMap linkAttributes = keyAttrs;
+    const auto constFieldPairs = mRelation.fieldPairs();
+    for ( const QgsRelation::FieldPair &fieldPair : constFieldPairs )
+    {
+      int index = fields.indexOf( fieldPair.first );
+      linkAttributes.insert( index,  mFeature.attribute( fieldPair.second ) );
+    }
 
-      updateUi();
+    const auto constNmFieldPairs = mNmRelation.fieldPairs();
+    for ( const QgsRelation::FieldPair &fieldPair : constNmFieldPairs )
+    {
+      int index = fields.indexOf( fieldPair.first );
+      linkAttributes.insert( index, f.attribute( fieldPair.second ) );
     }
+    QgsFeature linkFeature = QgsVectorLayerUtils::createFeature( mRelation.referencingLayer(), QgsGeometry(), linkAttributes, &context );
+
+    mRelation.referencingLayer()->addFeature( linkFeature );
   }
   else
   {
-    QgsFields fields = mRelation.referencingLayer()->fields();
-    if ( mRelation.type() == QgsRelation::Generated )
-    {
-      QgsPolymorphicRelation polyRel = mRelation.polymorphicRelation();
-      keyAttrs.insert( fields.indexFromName( polyRel.referencedLayerField() ), polyRel.layerRepresentation( mRelation.referencedLayer() ) );
-    }
-
     const auto constFieldPairs = mRelation.fieldPairs();
     for ( const QgsRelation::FieldPair &fieldPair : constFieldPairs )
     {
       keyAttrs.insert( fields.indexFromName( fieldPair.referencingField() ), mFeature.attribute( fieldPair.referencedField() ) );
     }
 
-    vlTools->addFeature( mRelation.referencingLayer(), keyAttrs, geometry );
+    if ( !vlTools->addFeature( mRelation.referencingLayer(), keyAttrs, geometry ) )
+      return;
   }
+
+  updateUi();
 }
 
 void QgsAbstractRelationEditorWidget::deleteFeature( const QgsFeatureId fid )
@@ -439,6 +440,16 @@ void QgsAbstractRelationEditorWidget::onLinkFeatureDlgAccepted()
     QgsExpressionContext context = mRelation.referencingLayer()->createExpressionContext();
 
     QgsAttributeMap linkAttributes;
+
+    if ( mRelation.type() == QgsRelation::Generated )
+    {
+      QgsPolymorphicRelation polyRel = mRelation.polymorphicRelation();
+      Q_ASSERT( polyRel.isValid() );
+
+      linkAttributes.insert( fields.indexFromName( polyRel.referencedLayerField() ),
+                             polyRel.layerRepresentation( mRelation.referencedLayer() ) );
+    }
+
     const auto constFieldPairs = mRelation.fieldPairs();
     for ( const QgsRelation::FieldPair &fieldPair : constFieldPairs )
     {
@@ -485,7 +496,7 @@ void QgsAbstractRelationEditorWidget::onLinkFeatureDlgAccepted()
       {
         QgsPolymorphicRelation polyRel = mRelation.polymorphicRelation();
 
-        Q_ASSERT( mRelation.polymorphicRelation().isValid() );
+        Q_ASSERT( polyRel.isValid() );
 
         mRelation.referencingLayer()->changeAttributeValue( fid,
             referencingLayer->fields().indexFromName( polyRel.referencedLayerField() ),
@@ -547,8 +558,6 @@ void QgsAbstractRelationEditorWidget::unlinkFeatures( const QgsFeatureIds &fids
     }
 
     mRelation.referencingLayer()->deleteFeatures( fids );
-
-    updateUi();
   }
   else
   {
@@ -589,6 +598,8 @@ void QgsAbstractRelationEditorWidget::unlinkFeatures( const QgsFeatureIds &fids
       }
     }
   }
+
+  updateUi();
 }
 
 void QgsAbstractRelationEditorWidget::updateUi()