[locator] add a way to invalidate results from python API

otherwise if you access the config of the filter (or change app settings) from outside the main application settings dialog, results are not invalidate

for instance, if you update a URL of a service, results won't be updated

python/gui/auto_generated/qgisinterface.sip.in

@@ -1102,6 +1102,15 @@ deregisterLocatorFilter() to deregister their filters upon plugin unload to avoi
 .. seealso:: :py:func:`registerLocatorFilter`
 
 .. versionadded:: 3.0
+%End
+
+    virtual void invalidateLocatorResults() = 0;
+%Docstring
+Invalidate results from the locator filter.
+
+This might be useful if the configuration of the filter changed without going through main application settings.
+
+.. versionadded:: 3.2
 %End
 
     virtual bool askForDatumTransform( QgsCoordinateReferenceSystem sourceCrs, QgsCoordinateReferenceSystem destinationCrs ) = 0;

src/app/qgisappinterface.cpp

@@ -774,6 +774,11 @@ void QgisAppInterface::deregisterLocatorFilter( QgsLocatorFilter *filter )
   qgis->mLocatorWidget->locator()->deregisterFilter( filter );
 }
 
+void QgisAppInterface::invalidateLocatorResults()
+{
+  qgis->mLocatorWidget->invalidateResults();
+}
+
 bool QgisAppInterface::askForDatumTransform( QgsCoordinateReferenceSystem sourceCrs, QgsCoordinateReferenceSystem destinationCrs )
 {
   return qgis->askUserForDatumTransform( sourceCrs, destinationCrs );

src/app/qgisappinterface.h

@@ -544,6 +544,7 @@ class APP_EXPORT QgisAppInterface : public QgisInterface
 
     void registerLocatorFilter( QgsLocatorFilter *filter ) override;
     void deregisterLocatorFilter( QgsLocatorFilter *filter ) override;
+    void invalidateLocatorResults() override;
 
     bool askForDatumTransform( QgsCoordinateReferenceSystem sourceCrs, QgsCoordinateReferenceSystem destinationCrs ) override;
 

src/gui/qgisinterface.h

@@ -902,6 +902,15 @@ class GUI_EXPORT QgisInterface : public QObject
      */
     virtual void deregisterLocatorFilter( QgsLocatorFilter *filter ) = 0;
 
+    /**
+     * Invalidate results from the locator filter.
+     *
+     * This might be useful if the configuration of the filter changed without going through main application settings.
+     *
+     * \since QGIS 3.2
+     */
+    virtual void invalidateLocatorResults() = 0;
+
     /**
       * Checks available datum transforms and ask user if several are available and none
       * is chosen. Dialog is shown only if global option is set accordingly.