Don't list join fields to facilitate 'save as' function (fixes #3857). Don't display the query builder if a layer has joins (#3858)

Author: Marco Hugentobler

src/app/qgsvectorlayerproperties.cpp

@@ -296,7 +296,8 @@ void QgsVectorLayerProperties::toggleEditing()
 {
   emit toggleEditing( layer );
 
-  pbnQueryBuilder->setEnabled( layer && layer->dataProvider() && layer->dataProvider()->supportsSubsetString() && !layer->isEditable() );
+  pbnQueryBuilder->setEnabled( layer && layer->dataProvider() && layer->dataProvider()->supportsSubsetString() &&
+                               !layer->isEditable() && layer->vectorJoins().size() < 1 );
   if ( layer->isEditable() )
   {
     pbnQueryBuilder->setToolTip( tr( "Stop editing mode to enable this." ) );
@@ -474,7 +475,8 @@ void QgsVectorLayerProperties::reset( void )
   // on the builder. If the ability to enter a query directly into the box is required,
   // a mechanism to check it must be implemented.
   txtSubsetSQL->setEnabled( false );
-  pbnQueryBuilder->setEnabled( layer && layer->dataProvider() && layer->dataProvider()->supportsSubsetString() && !layer->isEditable() );
+  pbnQueryBuilder->setEnabled( layer && layer->dataProvider() && layer->dataProvider()->supportsSubsetString() &&
+                               !layer->isEditable() && layer->vectorJoins().size() < 1 );
   if ( layer->isEditable() )
   {
     pbnQueryBuilder->setToolTip( tr( "Stop editing mode to enable this." ) );
@@ -1079,6 +1081,8 @@ void QgsVectorLayerProperties::on_mButtonAddJoin_clicked()
       layer->addJoin( info );
       loadRows(); //update attribute tab
       addJoinToTreeWidget( info );
+      pbnQueryBuilder->setEnabled( layer && layer->dataProvider() && layer->dataProvider()->supportsSubsetString() &&
+                                   !layer->isEditable() && layer->vectorJoins().size() < 1 );
     }
   }
 }
@@ -1116,6 +1120,8 @@ void QgsVectorLayerProperties::on_mButtonRemoveJoin_clicked()
   layer->removeJoin( currentJoinItem->data( 0, Qt::UserRole ).toString() );
   loadRows();
   mJoinTreeWidget->takeTopLevelItem( mJoinTreeWidget->indexOfTopLevelItem( currentJoinItem ) );
+  pbnQueryBuilder->setEnabled( layer && layer->dataProvider() && layer->dataProvider()->supportsSubsetString() &&
+                               !layer->isEditable() && layer->vectorJoins().size() < 1 );
 }
 
 void QgsVectorLayerProperties::handleDiagramItemDoubleClick( QTreeWidgetItem * item, int column )

src/core/qgsvectorlayer.cpp

@@ -2693,6 +2693,7 @@ bool QgsVectorLayer::readXml( const QDomNode& layer_node )
   mJoinBuffer->readXml( layer_node );
 
   updateFieldMap();
+  connect( QgsMapLayerRegistry::instance(), SIGNAL( layerWillBeRemoved( QString ) ), this, SLOT( checkJoinLayerRemove( QString ) ) );
 
   QString errorMsg;
   if ( !readSymbology( layer_node, errorMsg ) )

src/core/qgsvectorlayerjoinbuffer.cpp

@@ -96,7 +96,11 @@ void QgsVectorLayerJoinBuffer::updateFieldMap( QgsFieldMap& fields, int& maxInde
     QgsFieldMap::const_iterator fieldIt = joinFields.constBegin();
     for ( ; fieldIt != joinFields.constEnd(); ++fieldIt )
     {
-      fields.insert( maxIndex + 1 + fieldIt.key(), fieldIt.value() );
+      //skip the join field to avoid double field names (fields often have the same name)
+      if ( fieldIt.key() != joinIt->joinField )
+      {
+        fields.insert( maxIndex + 1 + fieldIt.key(), fieldIt.value() );
+      }
     }
 
     if ( maximumIndex( joinFields, currentMaxIndex ) )
@@ -217,6 +221,12 @@ void QgsVectorLayerJoinBuffer::addJoinedFeatureAttributes( QgsFeature& f, const
     QgsAttributeList::const_iterator attIt = attributes.constBegin();
     for ( ; attIt != attributes.constEnd(); ++attIt )
     {
+      //skip the join field to avoid double field names (fields often have the same name)
+      if ( *attIt == joinInfo.joinField )
+      {
+        continue;
+      }
+
       if ( found )
       {
         f.addAttribute( *attIt + attributeIndexOffset, featureAttributes.value( *attIt ) );

src/core/qgsvectorlayerjoinbuffer.h

@@ -24,7 +24,7 @@
 #include <QHash>
 #include <QString>
 
-/**Manages joined field for a vector layer*/
+/**Manages joined fields for a vector layer*/
 class CORE_EXPORT QgsVectorLayerJoinBuffer
 {
   public: