Fix Python based data providers on newer SIP versions

python/core/auto_generated/qgsfeaturerequest.sip.in

@@ -764,7 +764,9 @@ Base class that can be used for any class that is capable of returning features
   public:
     virtual ~QgsAbstractFeatureSource();
 
-    virtual QgsFeatureIterator getFeatures( const QgsFeatureRequest &request = QgsFeatureRequest() ) = 0;
+
+
+    virtual QgsFeatureIterator getFeatures( const QgsFeatureRequest &request = QgsFeatureRequest() ) = 0 /TransferBack/;
 %Docstring
 Gets an iterator for features matching the specified request
 
@@ -773,6 +775,7 @@ Gets an iterator for features matching the specified request
 :return: A feature iterator
 %End
 
+
   protected:
     void iteratorOpened( QgsAbstractFeatureIterator *it );
     void iteratorClosed( QgsAbstractFeatureIterator *it );

src/core/qgsfeaturerequest.h

@@ -744,12 +744,19 @@ class CORE_EXPORT QgsAbstractFeatureSource
   public:
     virtual ~QgsAbstractFeatureSource();
 
+
+    // IMPORTANT -- do NOT remove the /TransferBack/ annotation here -- while it looks completely wrong, it's
+    // required for Python data providers to work correctly! Argh!
+
     /**
      * Gets an iterator for features matching the specified request
      * \param request The request
      * \returns A feature iterator
      */
-    virtual QgsFeatureIterator getFeatures( const QgsFeatureRequest &request = QgsFeatureRequest() ) = 0;
+    virtual QgsFeatureIterator getFeatures( const QgsFeatureRequest &request = QgsFeatureRequest() ) = 0 SIP_TRANSFERBACK;
+
+    // IMPORTANT -- do NOT remove the /TransferBack/ annotation here -- while it looks completely wrong, it's
+    // required for Python data providers to work correctly! Argh!
 
   protected:
     void iteratorOpened( QgsAbstractFeatureIterator *it );