more explicit documentation

python/core/qgsvectordataprovider.sip

@@ -391,6 +391,13 @@ class QgsVectorDataProvider : QgsDataProvider
     void pushError( const QString& msg );
 
     /** Converts the geometry to the provider type if possible / necessary
+     * this is the list of possibile modifications:
+     * - convert compoundcurve to circularstring
+     *   (possible if compoundcurve consists of one circular string)
+     * - convert to multitype if necessary
+     * - convert to curved type if necessary
+     * - convert to linear type from curved type
+     * - Add or Remove z/m types
     @return the converted geometry or nullptr if no conversion was necessary or possible*/
     QgsGeometry* convertToProviderType( const QgsGeometry* geom ) const /Factory/;
 };

python/core/qgsvectorlayereditbuffer.sip

@@ -150,8 +150,9 @@ class QgsVectorLayerEditBuffer : QObject
     void updateLayerFields();
 
     /** Apply geometry modification basing on provider geometry type.
-     * Geometry is modified or  only if successful conversion is possible.
-     * In case of conversion a message is sent to the log.
+     * Geometry is modified only if successful conversion is possible.
+     * adaptGeometry calls QgsVectorDataProvider::convertToProviderType()
+     * if necessary and that apply the modifications.
      * @param geometry pointer to the geometry that should be adapted to provider
      * @return bool true if success.
      *  True: Input geometry is changed because conversion is applied or

src/core/qgsvectordataprovider.h

@@ -469,6 +469,13 @@ class CORE_EXPORT QgsVectorDataProvider : public QgsDataProvider
     QgsAttrPalIndexNameHash mAttrPalIndexName;
 
     /** Converts the geometry to the provider type if possible / necessary
+     * this is the list of possibile modifications:
+     * - convert compoundcurve to circularstring
+     *   (possible if compoundcurve consists of one circular string)
+     * - convert to multitype if necessary
+     * - convert to curved type if necessary
+     * - convert to linear type from curved type
+     * - Add or Remove z/m types
     @return the converted geometry or nullptr if no conversion was necessary or possible*/
     QgsGeometry* convertToProviderType( const QgsGeometry* geom ) const;
 

src/core/qgsvectorlayereditbuffer.h

@@ -180,7 +180,8 @@ class CORE_EXPORT QgsVectorLayerEditBuffer : public QObject
 
     /** Apply geometry modification basing on provider geometry type.
      * Geometry is modified only if successful conversion is possible.
-     * In case of conversion a message is sent to the log.
+     * adaptGeometry calls QgsVectorDataProvider::convertToProviderType()
+     * if necessary and that apply the modifications.
      * @param geometry pointer to the geometry that should be adapted to provider
      * @return bool true if success.
      *  True: Input geometry is changed because conversion is applied or