Fix compatibility with older sip versions

python/core/qgsvectorlayerfeaturecounter.sip

@@ -31,8 +31,13 @@ class QgsVectorLayerFeatureCounter : QgsTask
 
     virtual bool run();
 
+
   signals:
-    void symbolsCounted( const QHash<QString, long> &symbolFeatureCountMap );
+
+    void symbolsCounted();
+%Docstring
+ Emitted when the symbols have been counted.
+%End
 
 };
 

src/core/layertree/qgslayertreemodellegendnode.cpp

@@ -135,6 +135,7 @@ QgsSymbolLegendNode::QgsSymbolLegendNode( QgsLayerTreeLayer *nodeLayer, const Qg
   , mIconSize( 16, 16 )
 {
   updateLabel();
+  connect( qobject_cast<QgsVectorLayer*>( nodeLayer->layer() ), &QgsVectorLayer::symbolFeatureCountMapChanged, this, &QgsSymbolLegendNode::updateLabel );
 
   if ( mItem.symbol() )
     mSymbolUsesMapUnits = ( mItem.symbol()->outputUnit() != QgsUnitTypes::RenderMillimeters );

src/core/qgsvectorlayer.cpp

@@ -702,12 +702,12 @@ bool QgsVectorLayer::countSymbolFeatures()
 
   if ( !mFeatureCounter )
   {
-    mFeatureCounter.reset( new QgsVectorLayerFeatureCounter( this ) );
-    connect( mFeatureCounter.get(), &QgsVectorLayerFeatureCounter::symbolsCounted, this, &QgsVectorLayer::onSymbolsCounted );
-    connect( mFeatureCounter.get(), &QgsTask::taskCompleted, [ = ]() { mFeatureCounter.reset(); } );
-    connect( mFeatureCounter.get(), &QgsTask::taskTerminated, [ = ]() { mFeatureCounter.reset(); } );
+    mFeatureCounter = new QgsVectorLayerFeatureCounter( this );
+    connect( mFeatureCounter, &QgsVectorLayerFeatureCounter::symbolsCounted, this, &QgsVectorLayer::onSymbolsCounted );
+    connect( mFeatureCounter, &QgsTask::taskCompleted, [ = ]() { mFeatureCounter = nullptr; } );
+    connect( mFeatureCounter, &QgsTask::taskTerminated, [ = ]() { mFeatureCounter = nullptr; } );
 
-    QgsApplication::taskManager()->addTask( mFeatureCounter.get() );
+    QgsApplication::taskManager()->addTask( mFeatureCounter );
   }
 
   return true;
@@ -3899,11 +3899,14 @@ void QgsVectorLayer::onRelationsLoaded()
   mEditFormConfig.onRelationsLoaded();
 }
 
-void QgsVectorLayer::onSymbolsCounted( const QHash<QString, long> &symbolFeatureCountMap )
+void QgsVectorLayer::onSymbolsCounted()
 {
-  mSymbolFeatureCountMap = symbolFeatureCountMap;
-  mSymbolFeatureCounted = true;
-  emit symbolFeatureCountMapChanged();
+  if ( mFeatureCounter )
+  {
+    mSymbolFeatureCountMap = mFeatureCounter->symbolFeatureCountMap();
+    mSymbolFeatureCounted = true;
+    emit symbolFeatureCountMapChanged();
+  }
 }
 
 QList<QgsRelation> QgsVectorLayer::referencingRelations( int idx ) const

src/core/qgsvectorlayer.h

@@ -1858,7 +1858,7 @@ class CORE_EXPORT QgsVectorLayer : public QgsMapLayer, public QgsExpressionConte
     void onJoinedFieldsChanged();
     void onFeatureDeleted( QgsFeatureId fid );
     void onRelationsLoaded();
-    void onSymbolsCounted( const QHash<QString, long> &symbolFeatureCountMap );
+    void onSymbolsCounted();
 
   protected:
     //! Set the extent
@@ -2008,7 +2008,7 @@ class CORE_EXPORT QgsVectorLayer : public QgsMapLayer, public QgsExpressionConte
 
     mutable QMutex mFeatureSourceConstructorMutex;
 
-    std::unique_ptr<QgsVectorLayerFeatureCounter> mFeatureCounter;
+    QgsVectorLayerFeatureCounter *mFeatureCounter = nullptr;
 
     friend class QgsVectorLayerFeatureSource;
 };

src/core/qgsvectorlayerfeaturecounter.cpp

@@ -64,6 +64,11 @@ bool QgsVectorLayerFeatureCounter::run()
   mRenderer->stopRender( renderContext );
   setProgress( 100 );
 
-  emit symbolsCounted( mSymbolFeatureCountMap );
+  emit symbolsCounted();
   return true;
 }
+
+QHash<QString, long> QgsVectorLayerFeatureCounter::symbolFeatureCountMap() const
+{
+    return mSymbolFeatureCountMap;
+}

src/core/qgsvectorlayerfeaturecounter.h

@@ -28,8 +28,20 @@ class CORE_EXPORT QgsVectorLayerFeatureCounter : public QgsTask
 
     virtual bool run() override;
 
+    /**
+     * Get the count for each symbol. Only valid after the symbolsCounted()
+     * signal has been emitted.
+     *
+     * \note Not available in Python bindings.
+     */
+    QHash<QString, long> symbolFeatureCountMap() const SIP_SKIP;
+
   signals:
-    void symbolsCounted( const QHash<QString, long> &symbolFeatureCountMap );
+
+    /**
+     * Emitted when the symbols have been counted.
+     */
+    void symbolsCounted();
 
   private:
     std::unique_ptr<QgsVectorLayerFeatureSource> mSource;