pyqgis: add conversion to subclasses for QgsAbstractVectorLayerLabeling

Author: wonder-sk

python/core/qgsvectorlayerlabeling.sip.in

@@ -21,6 +21,14 @@ Abstract base class - its implementations define different approaches to the lab
 
 %TypeHeaderCode
 #include "qgsvectorlayerlabeling.h"
+%End
+%ConvertToSubClassCode
+    if ( sipCpp->type() == "simple" )
+      sipType = sipType_QgsVectorLayerSimpleLabeling;
+    else if ( sipCpp->type() == "rule-based" )
+      sipType = sipType_QgsRuleBasedLabeling;
+    else
+      sipType = 0;
 %End
   public:
     QgsAbstractVectorLayerLabeling();

src/core/qgsvectorlayerlabeling.h

@@ -39,6 +39,18 @@ class QgsVectorLayerLabelProvider;
  */
 class CORE_EXPORT QgsAbstractVectorLayerLabeling
 {
+
+#ifdef SIP_RUN
+    SIP_CONVERT_TO_SUBCLASS_CODE
+    if ( sipCpp->type() == "simple" )
+      sipType = sipType_QgsVectorLayerSimpleLabeling;
+    else if ( sipCpp->type() == "rule-based" )
+      sipType = sipType_QgsRuleBasedLabeling;
+    else
+      sipType = 0;
+    SIP_END
+#endif
+
   public:
     //! Default constructor
     QgsAbstractVectorLayerLabeling() = default;