Correctly utilise expression contexts for attribute form container vi…

…sibility - we shouldn't use a single member instance of the context here, because continually adding new scopes to that single instance will eventually cause the context to become massive and slow - correctly populate the context with the global/project/layer scopes Fixes #35558
qgis · Apr 20, 2020 · 4ca931d · 4ca931d
1 parent ea9613e
commit 4ca931d
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Showing 2 changed files with 16 additions and 11 deletions.
diff --git a/src/gui/qgsattributeform.cpp b/src/gui/qgsattributeform.cpp
@@ -306,7 +306,6 @@ void QgsAttributeForm::setFeature( const QgsFeature &feature )
     }
   }
   mIsSettingFeature = false;
-  mExpressionContext.setFeature( feature );
 }
 
 bool QgsAttributeForm::saveEdits()
@@ -951,28 +950,32 @@ void QgsAttributeForm::updateConstraints( QgsEditorWidgetWrapper *eww )
     // sync OK button status
     synchronizeEnabledState();
 
-    mExpressionContext.setFeature( ft );
-
-    mExpressionContext << QgsExpressionContextUtils::formScope( ft, mContext.attributeFormModeString() );
+    QgsExpressionContext context;
+    context.appendScopes( QgsExpressionContextUtils::globalProjectLayerScopes( mLayer ) );
+    context.appendScope( QgsExpressionContextUtils::formScope( ft, mContext.attributeFormModeString() ) );
+    context.setFeature( ft );
 
     // Recheck visibility for all containers which are controlled by this value
     const QVector<ContainerInformation *> infos = mContainerInformationDependency.value( eww->field().name() );
     for ( ContainerInformation *info : infos )
     {
-      info->apply( &mExpressionContext );
+      info->apply( &context );
     }
   }
 }
 
 void QgsAttributeForm::updateContainersVisibility()
 {
-  mExpressionContext << QgsExpressionContextUtils::formScope( QgsFeature( mFeature ), mContext.attributeFormModeString() );
+  QgsExpressionContext context;
+  context.appendScopes( QgsExpressionContextUtils::globalProjectLayerScopes( mLayer ) );
+  context.appendScope( QgsExpressionContextUtils::formScope( mFeature, mContext.attributeFormModeString() ) );
+  context.setFeature( mFeature );
 
   const QVector<ContainerInformation *> infos = mContainerVisibilityInformation;
 
   for ( ContainerInformation *info : infos )
   {
-    info->apply( &mExpressionContext );
+    info->apply( &context );
   }
 
   //and update the constraints
@@ -1014,13 +1017,16 @@ void QgsAttributeForm::updateLabels()
     QgsFeature currentFeature;
     if ( currentFormFeature( currentFeature ) )
     {
-      mExpressionContext << QgsExpressionContextUtils::formScope( currentFeature, mContext.attributeFormModeString() );
-      mExpressionContext.setFields( mLayer->fields() );
+      QgsExpressionContext context;
+      context.appendScopes( QgsExpressionContextUtils::globalProjectLayerScopes( mLayer ) );
+      context.appendScope( QgsExpressionContextUtils::formScope( currentFeature, mContext.attributeFormModeString() ) );
+      context.setFeature( currentFeature );
+
       for ( auto it = mLabelDataDefinedProperties.constBegin() ; it != mLabelDataDefinedProperties.constEnd(); ++it )
       {
         QLabel *label { it.key() };
         bool ok;
-        const QString value { it->valueAsString( mExpressionContext, QString(), &ok ) };
+        const QString value { it->valueAsString( context, QString(), &ok ) };
         if ( ok && ! value.isEmpty() )
         {
           label->setText( value );

diff --git a/src/gui/qgsattributeform.h b/src/gui/qgsattributeform.h
@@ -412,7 +412,6 @@ class GUI_EXPORT QgsAttributeForm : public QWidget
     QList<QgsAttributeFormInterface *> mInterfaces;
     QMap< int, QgsAttributeFormEditorWidget * > mFormEditorWidgets;
     QList< QgsAttributeFormWidget *> mFormWidgets;
-    QgsExpressionContext mExpressionContext;
     QMap<const QgsVectorLayerJoinInfo *, QgsFeature> mJoinedFeatures;
     QMap<QLabel *, QgsProperty> mLabelDataDefinedProperties;
     bool mValuesInitialized = false;