Fix #12165 - table can't be joined multiple times

Author: wonder-sk

src/core/qgsvectorlayerfeatureiterator.cpp

@@ -453,7 +453,7 @@ void QgsVectorLayerFeatureIterator::prepareJoins()
     QgsVectorLayer* joinLayer = qobject_cast<QgsVectorLayer*>( QgsMapLayerRegistry::instance()->mapLayer( joinInfo->joinLayerId ) );
     Q_ASSERT( joinLayer );
 
-    if ( !mFetchJoinInfo.contains( joinLayer ) )
+    if ( !mFetchJoinInfo.contains( joinInfo ) )
     {
       FetchJoinInfo info;
       info.joinInfo = joinInfo;
@@ -474,11 +474,11 @@ void QgsVectorLayerFeatureIterator::prepareJoins()
       if ( !fetchAttributes.contains( info.targetField ) )
         sourceJoinFields << info.targetField;
 
-      mFetchJoinInfo.insert( joinLayer, info );
+      mFetchJoinInfo.insert( joinInfo, info );
     }
 
     // store field source index - we'll need it when fetching from provider
-    mFetchJoinInfo[ joinLayer ].attributes.push_back( sourceLayerIndex );
+    mFetchJoinInfo[ joinInfo ].attributes.push_back( sourceLayerIndex );
   }
 
   // add sourceJoinFields if we're using a subset
@@ -525,7 +525,7 @@ void QgsVectorLayerFeatureIterator::prepareExpressions()
 
 void QgsVectorLayerFeatureIterator::addJoinedAttributes( QgsFeature &f )
 {
-  QMap<QgsVectorLayer*, FetchJoinInfo>::const_iterator joinIt = mFetchJoinInfo.constBegin();
+  QMap<const QgsVectorJoinInfo*, FetchJoinInfo>::const_iterator joinIt = mFetchJoinInfo.constBegin();
   for ( ; joinIt != mFetchJoinInfo.constEnd(); ++joinIt )
   {
     const FetchJoinInfo& info = joinIt.value();

src/core/qgsvectorlayerfeatureiterator.h

@@ -148,7 +148,7 @@ class CORE_EXPORT QgsVectorLayerFeatureIterator : public QgsAbstractFeatureItera
 
     /** information about joins used in the current select() statement.
       Allows faster mapping of attribute ids compared to mVectorJoins */
-    QMap<QgsVectorLayer*, FetchJoinInfo> mFetchJoinInfo;
+    QMap<const QgsVectorJoinInfo*, FetchJoinInfo> mFetchJoinInfo;
 
     QMap<int, QgsExpression*> mExpressionFieldInfo;
 

tests/src/core/testqgsvectorlayerjoinbuffer.cpp

@@ -52,6 +52,7 @@ class TestVectorLayerJoinBuffer : public QObject
     void testJoinDetectCycle();
     void testJoinSubset_data();
     void testJoinSubset();
+    void testJoinTwoTimes();
 
   private:
     QgsVectorLayer* mLayerA;
@@ -301,6 +302,44 @@ void TestVectorLayerJoinBuffer::testJoinSubset()
 }
 
 
+void TestVectorLayerJoinBuffer::testJoinTwoTimes()
+{
+  QVERIFY( mLayerA->pendingFields().count() == 1 );
+
+  QgsVectorJoinInfo joinInfo1;
+  joinInfo1.targetFieldName = "id_a";
+  joinInfo1.joinLayerId = mLayerB->id();
+  joinInfo1.joinFieldName = "id_b";
+  joinInfo1.memoryCache = true;
+  joinInfo1.prefix = "j1_";
+  mLayerA->addJoin( joinInfo1 );
+
+  QgsVectorJoinInfo joinInfo2;
+  joinInfo2.targetFieldName = "id_a";
+  joinInfo2.joinLayerId = mLayerB->id();
+  joinInfo2.joinFieldName = "id_b";
+  joinInfo2.memoryCache = true;
+  joinInfo2.prefix = "j2_";
+  mLayerA->addJoin( joinInfo2 );
+
+  QCOMPARE( mLayerA->vectorJoins().count(), 2 );
+
+  QVERIFY( mLayerA->pendingFields().count() == 3 );
+
+  QgsFeatureIterator fi = mLayerA->getFeatures();
+  QgsFeature fA1; //, fA2;
+  fi.nextFeature( fA1 );
+  QCOMPARE( fA1.attribute( "id_a" ).toInt(), 1 );
+  QCOMPARE( fA1.attribute( "j1_value_b" ).toInt(), 11 );
+  QCOMPARE( fA1.attribute( "j2_value_b" ).toInt(), 11 );
+
+  mLayerA->removeJoin( mLayerB->id() );
+  mLayerA->removeJoin( mLayerB->id() );
+
+  QCOMPARE( mLayerA->vectorJoins().count(), 0 );
+}
+
+
 QTEST_MAIN( TestVectorLayerJoinBuffer )
 #include "testqgsvectorlayerjoinbuffer.moc"