Gracefully handle empty existing property values when creating auxiliary

fields Fixes #46403
qgis · Feb 2, 2022 · 1f1e616 · 1f1e616
1 parent 20c289e
commit 1f1e616
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Showing 2 changed files with 37 additions and 1 deletion.
diff --git a/src/core/qgsauxiliarystorage.cpp b/src/core/qgsauxiliarystorage.cpp
@@ -244,7 +244,10 @@ int QgsAuxiliaryLayer::createProperty( QgsPalLayerSettings::Property property, Q
 
         // is there an existing property?
         const QgsProperty existingProperty = c.property( property );
-        if ( existingProperty.propertyType() == QgsProperty::InvalidProperty || overwriteExisting )
+        if ( existingProperty.propertyType() == QgsProperty::InvalidProperty
+             || ( existingProperty.propertyType() == QgsProperty::FieldBasedProperty && existingProperty.field().isEmpty() )
+             || ( existingProperty.propertyType() == QgsProperty::ExpressionBasedProperty && existingProperty.expressionString().isEmpty() )
+             || overwriteExisting )
         {
           const QgsProperty prop = QgsProperty::fromField( fieldName );
           c.setProperty( property, prop );

diff --git a/tests/src/python/test_qgsauxiliarystorage.py b/tests/src/python/test_qgsauxiliarystorage.py
@@ -429,6 +429,39 @@ def testCreateProperty(self):
         self.assertTrue(settings.dataDefinedProperties().property(key).isActive())
         self.assertEqual(settings.dataDefinedProperties().property(key).asExpression(), 'coalesce("auxiliary_storage_labeling_positiony",$y + 20)')
 
+        # with existing but invalid field name
+        key = QgsPalLayerSettings.PositionY
+        settings = QgsPalLayerSettings()
+        settings.dataDefinedProperties().setProperty(key, QgsProperty.fromField(''))
+        vl.setLabeling(QgsVectorLayerSimpleLabeling(settings))
+
+        # even when asked to not overwrite existing, this is an invalid property and should be overwritten
+        index = QgsAuxiliaryLayer.createProperty(key, vl, False)
+        p = QgsPalLayerSettings.propertyDefinitions()[key]
+        afName = QgsAuxiliaryLayer.nameFromProperty(p, True)
+        afIndex = vl.fields().indexOf(afName)
+        self.assertEqual(index, afIndex)
+
+        settings = vl.labeling().settings()
+        self.assertTrue(settings.dataDefinedProperties().property(key).isActive())
+        self.assertEqual(settings.dataDefinedProperties().property(key).asExpression(), '"auxiliary_storage_labeling_positiony"')
+
+        # with existing valid field name
+        key = QgsPalLayerSettings.PositionY
+        settings = QgsPalLayerSettings()
+        settings.dataDefinedProperties().setProperty(key, QgsProperty.fromField('asd'))
+        vl.setLabeling(QgsVectorLayerSimpleLabeling(settings))
+
+        index = QgsAuxiliaryLayer.createProperty(key, vl, False)
+        p = QgsPalLayerSettings.propertyDefinitions()[key]
+        afName = QgsAuxiliaryLayer.nameFromProperty(p, True)
+        afIndex = vl.fields().indexOf(afName)
+        self.assertEqual(index, afIndex)
+
+        settings = vl.labeling().settings()
+        self.assertTrue(settings.dataDefinedProperties().property(key).isActive())
+        self.assertEqual(settings.dataDefinedProperties().property(key).asExpression(), 'coalesce("auxiliary_storage_labeling_positiony","asd")')
+
         # with overwrite existing
         key = QgsPalLayerSettings.Show
         settings = QgsPalLayerSettings()