Classifications on joined fields should only consider values which

are matched to layer's features (fix #9051)

src/core/qgsvectorlayer.cpp

@@ -3136,12 +3136,12 @@ void QgsVectorLayer::uniqueValues( int index, QList<QVariant> &uniqueValues, int
   }
 
   QgsFields::FieldOrigin origin = mUpdatedFields.fieldOrigin( index );
-  if ( origin == QgsFields::OriginUnknown )
+  switch ( origin )
   {
+    case QgsFields::OriginUnknown:
       return;
-  }
 
-  if ( origin == QgsFields::OriginProvider ) //a provider field
+    case QgsFields::OriginProvider: //a provider field
     {
       mDataProvider->uniqueValues( index, uniqueValues, limit );
 
@@ -3172,29 +3172,22 @@ void QgsVectorLayer::uniqueValues( int index, QList<QVariant> &uniqueValues, int
 
       return;
     }
-  else if ( origin == QgsFields::OriginJoin )
-  {
-    int sourceLayerIndex;
-    const QgsVectorJoinInfo* join = mJoinBuffer->joinForFieldIndex( index, mUpdatedFields, sourceLayerIndex );
-    Q_ASSERT( join );
 
-    QgsVectorLayer *vl = dynamic_cast<QgsVectorLayer*>( QgsMapLayerRegistry::instance()->mapLayer( join->joinLayerId ) );
+    case QgsFields::OriginEdit:
-
-    if ( vl )
-      vl->dataProvider()->uniqueValues( sourceLayerIndex, uniqueValues, limit );
-
-    return;
-  }
-  else if ( origin == QgsFields::OriginEdit || origin == QgsFields::OriginExpression )
-  {
       // the layer is editable, but in certain cases it can still be avoided going through all features
-    if ( origin == QgsFields::OriginEdit && mEditBuffer->mDeletedFeatureIds.isEmpty() && mEditBuffer->mAddedFeatures.isEmpty() && !mEditBuffer->mDeletedAttributeIds.contains( index ) && mEditBuffer->mChangedAttributeValues.isEmpty() )
+      if ( mEditBuffer->mDeletedFeatureIds.isEmpty() &&
+           mEditBuffer->mAddedFeatures.isEmpty() &&
+           !mEditBuffer->mDeletedAttributeIds.contains( index ) &&
+           mEditBuffer->mChangedAttributeValues.isEmpty() )
       {
         mDataProvider->uniqueValues( index, uniqueValues, limit );
         return;
       }
-
+      FALLTHROUGH
       //we need to go through each feature
+    case QgsFields::OriginJoin:
+    case QgsFields::OriginExpression:
+    {
       QgsAttributeList attList;
       attList << index;
 
@@ -3218,6 +3211,7 @@ void QgsVectorLayer::uniqueValues( int index, QList<QVariant> &uniqueValues, int
       uniqueValues = val.values();
       return;
     }
+  }
 
   Q_ASSERT_X( false, "QgsVectorLayer::uniqueValues()", "Unknown source of the field!" );
 }
@@ -3230,38 +3224,31 @@ QVariant QgsVectorLayer::minimumValue( int index )
   }
 
   QgsFields::FieldOrigin origin = mUpdatedFields.fieldOrigin( index );
-  if ( origin == QgsFields::OriginUnknown )
+
+  switch ( origin )
   {
+    case QgsFields::OriginUnknown:
       return QVariant();
-  }
 
-  if ( origin == QgsFields::OriginProvider ) //a provider field
+    case QgsFields::OriginProvider: //a provider field
-  {
       return mDataProvider->minimumValue( index );
-  }
-  else if ( origin == QgsFields::OriginJoin )
-  {
-    int sourceLayerIndex;
-    const QgsVectorJoinInfo* join = mJoinBuffer->joinForFieldIndex( index, mUpdatedFields, sourceLayerIndex );
-    Q_ASSERT( join );
 
-    QgsVectorLayer* vl = dynamic_cast<QgsVectorLayer*>( QgsMapLayerRegistry::instance()->mapLayer( join->joinLayerId ) );
+    case QgsFields::OriginEdit:
-    Q_ASSERT( vl );
-
-    return vl->minimumValue( sourceLayerIndex );
-  }
-  else if ( origin == QgsFields::OriginEdit || origin == QgsFields::OriginExpression )
     {
       // the layer is editable, but in certain cases it can still be avoided going through all features
-    if ( origin == QgsFields::OriginEdit &&
+      if ( mEditBuffer->mDeletedFeatureIds.isEmpty() &&
-         mEditBuffer->mDeletedFeatureIds.isEmpty() &&
            mEditBuffer->mAddedFeatures.isEmpty() && !
            mEditBuffer->mDeletedAttributeIds.contains( index ) &&
            mEditBuffer->mChangedAttributeValues.isEmpty() )
       {
         return mDataProvider->minimumValue( index );
       }
-
+    }
+    FALLTHROUGH
+    // no choice but to go through all features
+    case QgsFields::OriginExpression:
+    case QgsFields::OriginJoin:
+    {
       // we need to go through each feature
       QgsAttributeList attList;
       attList << index;
@@ -3283,6 +3270,7 @@ QVariant QgsVectorLayer::minimumValue( int index )
       }
       return QVariant( minimumValue );
     }
+  }
 
   Q_ASSERT_X( false, "QgsVectorLayer::minimumValue()", "Unknown source of the field!" );
   return QVariant();
@@ -3296,31 +3284,17 @@ QVariant QgsVectorLayer::maximumValue( int index )
   }
 
   QgsFields::FieldOrigin origin = mUpdatedFields.fieldOrigin( index );
-  if ( origin == QgsFields::OriginUnknown )
+  switch ( origin )
   {
+    case QgsFields::OriginUnknown:
       return QVariant();
-  }
 
-  if ( origin == QgsFields::OriginProvider ) //a provider field
+    case QgsFields::OriginProvider: //a provider field
-  {
       return mDataProvider->maximumValue( index );
-  }
-  else if ( origin == QgsFields::OriginJoin )
-  {
-    int sourceLayerIndex;
-    const QgsVectorJoinInfo* join = mJoinBuffer->joinForFieldIndex( index, mUpdatedFields, sourceLayerIndex );
-    Q_ASSERT( join );
 
-    QgsVectorLayer* vl = dynamic_cast<QgsVectorLayer*>( QgsMapLayerRegistry::instance()->mapLayer( join->joinLayerId ) );
+    case QgsFields::OriginEdit:
-    Q_ASSERT( vl );
-
-    return vl->maximumValue( sourceLayerIndex );
-  }
-  else if ( origin == QgsFields::OriginEdit || origin == QgsFields::OriginExpression )
-  {
       // the layer is editable, but in certain cases it can still be avoided going through all features
-    if ( origin == QgsFields::OriginEdit &&
+      if ( mEditBuffer->mDeletedFeatureIds.isEmpty() &&
-         mEditBuffer->mDeletedFeatureIds.isEmpty() &&
            mEditBuffer->mAddedFeatures.isEmpty() &&
            !mEditBuffer->mDeletedAttributeIds.contains( index ) &&
            mEditBuffer->mChangedAttributeValues.isEmpty() )
@@ -3328,7 +3302,11 @@ QVariant QgsVectorLayer::maximumValue( int index )
         return mDataProvider->maximumValue( index );
       }
 
-    // we need to go through each feature
+      FALLTHROUGH
+      //no choice but to go through each feature
+    case QgsFields::OriginJoin:
+    case QgsFields::OriginExpression:
+    {
       QgsAttributeList attList;
       attList << index;
 
@@ -3349,6 +3327,7 @@ QVariant QgsVectorLayer::maximumValue( int index )
       }
       return QVariant( maximumValue );
     }
+  }
 
   Q_ASSERT_X( false, "QgsVectorLayer::maximumValue()", "Unknown source of the field!" );
   return QVariant();

tests/src/python/test_qgsvectorlayer.py

@@ -59,6 +59,21 @@ def createLayerWithOnePoint():
     return layer
 
 
+def createLayerWithTwoPoints():
+    layer = QgsVectorLayer("Point?field=fldtxt:string&field=fldint:integer",
+                           "addfeat", "memory")
+    pr = layer.dataProvider()
+    f = QgsFeature()
+    f.setAttributes(["test", 123])
+    f.setGeometry(QgsGeometry.fromPoint(QgsPoint(100, 200)))
+    f2 = QgsFeature()
+    f2.setAttributes(["test2", 457])
+    f2.setGeometry(QgsGeometry.fromPoint(QgsPoint(100, 200)))
+    assert pr.addFeatures([f, f2])
+    assert layer.pendingFeatureCount() == 2
+    return layer
+
+
 def createJoinLayer():
     joinLayer = QgsVectorLayer(
         "Point?field=x:string&field=y:integer&field=z:integer",
@@ -70,8 +85,14 @@ def createJoinLayer():
     f2 = QgsFeature()
     f2.setAttributes(["bar", 456, 654])
     f2.setGeometry(QgsGeometry.fromPoint(QgsPoint(2, 2)))
-    assert pr.addFeatures([f1, f2])
+    f3 = QgsFeature()
-    assert joinLayer.pendingFeatureCount() == 2
+    f3.setAttributes(["qar", 457, 111])
+    f3.setGeometry(QgsGeometry.fromPoint(QgsPoint(2, 2)))
+    f4 = QgsFeature()
+    f4.setAttributes(["a", 458, 19])
+    f4.setGeometry(QgsGeometry.fromPoint(QgsPoint(2, 2)))
+    assert pr.addFeatures([f1, f2, f3, f4])
+    assert joinLayer.pendingFeatureCount() == 4
     return joinLayer
 
 
@@ -1083,6 +1104,24 @@ class TestQgsVectorLayer(unittest.TestCase):
         self.assertEqual(f2[2], "foo")
         self.assertEqual(f2[3], 321)
 
+    def test_JoinStats(self):
+        """ test calculating min/max/uniqueValues on joined field """
+        joinLayer = createJoinLayer()
+        layer = createLayerWithTwoPoints()
+        QgsMapLayerRegistry.instance().addMapLayers([joinLayer, layer])
+
+        join = QgsVectorJoinInfo()
+        join.targetFieldName = "fldint"
+        join.joinLayerId = joinLayer.id()
+        join.joinFieldName = "y"
+        join.memoryCache = True
+        layer.addJoin(join)
+
+        # stats on joined fields should only include values present by join
+        self.assertEqual(layer.minimumValue(3), 111)
+        self.assertEqual(layer.maximumValue(3), 321)
+        self.assertEqual(set(layer.uniqueValues(3)), set([111, 321]))
+
     def test_InvalidOperations(self):
         layer = createLayerWithOnePoint()