[atribute form] Add parent context when editing a child feature throu…

…gh the relation editor widget

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

@@ -1777,7 +1777,7 @@ be updated. This can be used to override default field value expressions.
 .. seealso:: :py:func:`updateFeature`
 %End
 
-    bool changeAttributeValue( QgsFeatureId fid, int field, const QVariant &newValue, const QVariant &oldValue = QVariant(), bool skipDefaultValues = false );
+    bool changeAttributeValue( QgsFeatureId fid, int field, const QVariant &newValue, const QVariant &oldValue = QVariant(), bool skipDefaultValues = false,  QgsExpressionContext *context = 0 );
 %Docstring
 Changes an attribute value for a feature (but does not immediately commit the changes).
 The ``fid`` argument specifies the ID of the feature to be changed.
@@ -1796,6 +1796,8 @@ so it is more efficient to explicitly pass an ``oldValue`` if it is already avai
 If ``skipDefaultValues`` is set to ``True``, default field values will not
 be updated. This can be used to override default field value expressions.
 
+If ``context`` is provided, it will be used when updating default values.
+
 :return: ``True`` if the feature's attribute was successfully changed.
 
 .. note::
@@ -1815,7 +1817,7 @@ be updated. This can be used to override default field value expressions.
 .. seealso:: :py:func:`updateFeature`
 %End
 
-    bool changeAttributeValues( QgsFeatureId fid, const QgsAttributeMap &newValues, const QgsAttributeMap &oldValues = QgsAttributeMap(), bool skipDefaultValues = false );
+    bool changeAttributeValues( QgsFeatureId fid, const QgsAttributeMap &newValues, const QgsAttributeMap &oldValues = QgsAttributeMap(), bool skipDefaultValues = false, QgsExpressionContext *context = 0 );
 %Docstring
 Changes attributes' values for a feature (but does not immediately
 commit the changes).
@@ -1835,6 +1837,8 @@ If ``skipDefaultValues`` is set to ``True``, default field values will not
 be updated. This can be used to override default field value
 expressions.
 
+If ``context`` is provided, it will be used when updating default values.
+
 :return: ``True`` if feature's attributes was successfully changed.
 
 .. note::

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

@@ -1777,7 +1777,7 @@ be updated. This can be used to override default field value expressions.
 .. seealso:: :py:func:`updateFeature`
 %End
 
-    bool changeAttributeValue( QgsFeatureId fid, int field, const QVariant &newValue, const QVariant &oldValue = QVariant(), bool skipDefaultValues = false );
+    bool changeAttributeValue( QgsFeatureId fid, int field, const QVariant &newValue, const QVariant &oldValue = QVariant(), bool skipDefaultValues = false,  QgsExpressionContext *context = 0 );
 %Docstring
 Changes an attribute value for a feature (but does not immediately commit the changes).
 The ``fid`` argument specifies the ID of the feature to be changed.
@@ -1796,6 +1796,8 @@ so it is more efficient to explicitly pass an ``oldValue`` if it is already avai
 If ``skipDefaultValues`` is set to ``True``, default field values will not
 be updated. This can be used to override default field value expressions.
 
+If ``context`` is provided, it will be used when updating default values.
+
 :return: ``True`` if the feature's attribute was successfully changed.
 
 .. note::
@@ -1815,7 +1817,7 @@ be updated. This can be used to override default field value expressions.
 .. seealso:: :py:func:`updateFeature`
 %End
 
-    bool changeAttributeValues( QgsFeatureId fid, const QgsAttributeMap &newValues, const QgsAttributeMap &oldValues = QgsAttributeMap(), bool skipDefaultValues = false );
+    bool changeAttributeValues( QgsFeatureId fid, const QgsAttributeMap &newValues, const QgsAttributeMap &oldValues = QgsAttributeMap(), bool skipDefaultValues = false, QgsExpressionContext *context = 0 );
 %Docstring
 Changes attributes' values for a feature (but does not immediately
 commit the changes).
@@ -1835,6 +1837,8 @@ If ``skipDefaultValues`` is set to ``True``, default field values will not
 be updated. This can be used to override default field value
 expressions.
 
+If ``context`` is provided, it will be used when updating default values.
+
 :return: ``True`` if feature's attributes was successfully changed.
 
 .. note::

src/core/vector/qgsvectorlayer.cpp

@@ -1002,7 +1002,7 @@ void QgsVectorLayer::setExtent3D( const QgsBox3D &r )
   mValidExtent3D = true;
 }
 
-void QgsVectorLayer::updateDefaultValues( QgsFeatureId fid, QgsFeature feature )
+void QgsVectorLayer::updateDefaultValues( QgsFeatureId fid, QgsFeature feature, QgsExpressionContext *context )
 {
   QGIS_PROTECT_QOBJECT_THREAD_ACCESS
 
@@ -1016,7 +1016,7 @@ void QgsVectorLayer::updateDefaultValues( QgsFeatureId fid, QgsFeature feature )
     {
       if ( idx < 0 || idx >= size )
         continue;
-      feature.setAttribute( idx, defaultValue( idx, feature ) );
+      feature.setAttribute( idx, defaultValue( idx, feature, context ) );
       updateFeature( feature, true );
     }
   }
@@ -3398,7 +3398,7 @@ bool QgsVectorLayer::changeGeometry( QgsFeatureId fid, QgsGeometry &geom, bool s
 }
 
 
-bool QgsVectorLayer::changeAttributeValue( QgsFeatureId fid, int field, const QVariant &newValue, const QVariant &oldValue, bool skipDefaultValues )
+bool QgsVectorLayer::changeAttributeValue( QgsFeatureId fid, int field, const QVariant &newValue, const QVariant &oldValue, bool skipDefaultValues, QgsExpressionContext *context )
 {
   QGIS_PROTECT_QOBJECT_THREAD_ACCESS
 
@@ -3426,12 +3426,12 @@ bool QgsVectorLayer::changeAttributeValue( QgsFeatureId fid, int field, const QV
   }
 
   if ( result && !skipDefaultValues && !mDefaultValueOnUpdateFields.isEmpty() )
-    updateDefaultValues( fid );
+    updateDefaultValues( fid, QgsFeature(), context );
 
   return result;
 }
 
-bool QgsVectorLayer::changeAttributeValues( QgsFeatureId fid, const QgsAttributeMap &newValues, const QgsAttributeMap &oldValues, bool skipDefaultValues )
+bool QgsVectorLayer::changeAttributeValues( QgsFeatureId fid, const QgsAttributeMap &newValues, const QgsAttributeMap &oldValues, bool skipDefaultValues, QgsExpressionContext *context )
 {
   QGIS_PROTECT_QOBJECT_THREAD_ACCESS
 
@@ -3488,7 +3488,7 @@ bool QgsVectorLayer::changeAttributeValues( QgsFeatureId fid, const QgsAttribute
 
   if ( result && !skipDefaultValues && !mDefaultValueOnUpdateFields.isEmpty() )
   {
-    updateDefaultValues( fid );
+    updateDefaultValues( fid, QgsFeature(), context );
   }
 
   return result;

src/core/vector/qgsvectorlayer.h

@@ -1735,6 +1735,8 @@ class CORE_EXPORT QgsVectorLayer : public QgsMapLayer, public QgsExpressionConte
      * If \a skipDefaultValues is set to TRUE, default field values will not
      * be updated. This can be used to override default field value expressions.
      *
+     * If \a context is provided, it will be used when updating default values.
+     *
      * \returns TRUE if the feature's attribute was successfully changed.
      *
      * \note Calls to changeAttributeValue() are only valid for layers in which edits have been enabled
@@ -1747,7 +1749,7 @@ class CORE_EXPORT QgsVectorLayer : public QgsMapLayer, public QgsExpressionConte
      * \see changeGeometry()
      * \see updateFeature()
      */
-    Q_INVOKABLE bool changeAttributeValue( QgsFeatureId fid, int field, const QVariant &newValue, const QVariant &oldValue = QVariant(), bool skipDefaultValues = false );
+    Q_INVOKABLE bool changeAttributeValue( QgsFeatureId fid, int field, const QVariant &newValue, const QVariant &oldValue = QVariant(), bool skipDefaultValues = false,  QgsExpressionContext *context = nullptr );
 
     /**
      * Changes attributes' values for a feature (but does not immediately
@@ -1768,6 +1770,8 @@ class CORE_EXPORT QgsVectorLayer : public QgsMapLayer, public QgsExpressionConte
      * be updated. This can be used to override default field value
      * expressions.
      *
+     * If \a context is provided, it will be used when updating default values.
+     *
      * \returns TRUE if feature's attributes was successfully changed.
      *
      * \note Calls to changeAttributeValues() are only valid for layers in
@@ -1783,7 +1787,7 @@ class CORE_EXPORT QgsVectorLayer : public QgsMapLayer, public QgsExpressionConte
      * \see changeAttributeValue()
      *
      */
-    Q_INVOKABLE bool changeAttributeValues( QgsFeatureId fid, const QgsAttributeMap &newValues, const QgsAttributeMap &oldValues = QgsAttributeMap(), bool skipDefaultValues = false );
+    Q_INVOKABLE bool changeAttributeValues( QgsFeatureId fid, const QgsAttributeMap &newValues, const QgsAttributeMap &oldValues = QgsAttributeMap(), bool skipDefaultValues = false, QgsExpressionContext *context = nullptr );
 
     /**
      * Add an attribute field (but does not commit it)
@@ -2794,7 +2798,7 @@ class CORE_EXPORT QgsVectorLayer : public QgsMapLayer, public QgsExpressionConte
     void onAfterCommitChangesDependency();
 
   private:
-    void updateDefaultValues( QgsFeatureId fid, QgsFeature feature = QgsFeature() );
+    void updateDefaultValues( QgsFeatureId fid, QgsFeature feature = QgsFeature(), QgsExpressionContext *context = nullptr );
 
     /**
      * Returns TRUE if the layer is in read-only mode

src/gui/attributeformconfig/qgsattributetypedialog.cpp

@@ -352,6 +352,7 @@ QgsExpressionContext QgsAttributeTypeDialog::createExpressionContext() const
       << QgsExpressionContextUtils::projectScope( QgsProject::instance() )
       << QgsExpressionContextUtils::layerScope( mLayer )
       << QgsExpressionContextUtils::formScope( )
+      << QgsExpressionContextUtils::parentFormScope( QgsFeature() )
       << QgsExpressionContextUtils::mapToolCaptureScope( QList<QgsPointLocator::Match>() );
 
   return context;

src/gui/qgsattributeform.cpp

@@ -353,7 +353,9 @@ bool QgsAttributeForm::saveEdits( QString *error )
     // An add dialog should perform an action by default
     // and not only if attributes have "changed"
     if ( mMode == QgsAttributeEditorContext::AddFeatureMode || mMode == QgsAttributeEditorContext::FixAttributeMode )
+    {
       doUpdate = true;
+    }
 
     QgsAttributes src = mFeature.attributes();
     QgsAttributes dst = mFeature.attributes();
@@ -461,7 +463,8 @@ bool QgsAttributeForm::saveEdits( QString *error )
           n++;
         }
 
-        success = mLayer->changeAttributeValues( mFeature.id(), newValues, oldValues );
+        QgsExpressionContext context = createExpressionContext( updatedFeature );
+        success = mLayer->changeAttributeValues( mFeature.id(), newValues, oldValues, false, &context );
 
         if ( success && n > 0 )
         {
@@ -569,6 +572,7 @@ void QgsAttributeForm::updateValuesDependenciesDefaultValues( const int originId
         continue;
 
       QgsExpressionContext context = createExpressionContext( updatedFeature );
+
       const QVariant value = mLayer->defaultValue( eww->fieldIdx(), updatedFeature, &context );
       eww->setValue( value );
       mCurrentFormFeature.setAttribute( eww->field().name(), value );
@@ -983,7 +987,13 @@ QgsExpressionContext QgsAttributeForm::createExpressionContext( const QgsFeature
   context.appendScopes( QgsExpressionContextUtils::globalProjectLayerScopes( mLayer ) );
   context.appendScope( QgsExpressionContextUtils::formScope( feature, mContext.attributeFormModeString() ) );
   if ( mExtraContextScope )
+  {
     context.appendScope( new QgsExpressionContextScope( *mExtraContextScope.get() ) );
+  }
+  if ( mContext.parentFormFeature().isValid() )
+  {
+    context.appendScope( QgsExpressionContextUtils::parentFormScope( mContext.parentFormFeature() ) );
+  }
   context.setFeature( feature );
   return context;
 }

tests/src/python/test_qgsrelationeditwidget.py

@@ -341,7 +341,7 @@ def test_add_feature_geometry(self):
         # Mock vector layer tool to just set default value on created feature
         class DummyVlTools(QgsVectorLayerTools):
 
-            def addFeature(self, layer, defaultValues, defaultGeometry, parentWidget=None, showModal=True, hideParent=False):
+            def addFeature(self, layer, defaultValues, defaultGeometry, parentWidget=None, showModal=True, hideParent=False, scope=None):
                 f = QgsFeature(layer.fields())
                 for idx, value in defaultValues.items():
                     f.setAttribute(idx, value)
@@ -440,7 +440,7 @@ def setValues(self, values):
         """
         self.values = values
 
-    def addFeature(self, layer, defaultValues, defaultGeometry, parentWidget=None, showModal=True, hideParent=False):
+    def addFeature(self, layer, defaultValues, defaultGeometry, parentWidget=None, showModal=True, hideParent=False, scope=None):
         """
         Overrides the addFeature method
         :param layer: vector layer