[processing] Correctly handle when no feedback object is passed

Author: nyalldawson

python/plugins/processing/algs/qgis/Datasources2Vrt.py

@@ -31,7 +31,7 @@
 import xml.sax.saxutils
 
 from osgeo import ogr
-
+from qgis.core import QgsProcessingFeedback
 from processing.tools import dataobjects
 from processing.core.GeoAlgorithm import GeoAlgorithm
 from processing.core.GeoAlgorithmExecutionException import GeoAlgorithmExecutionException
@@ -90,6 +90,9 @@ def mergeDataSources2Vrt(self, dataSources, outFile, union=False, relative=False
         @param schema: Schema flag
         @return: vrt in string format
         '''
+        if feedback is None:
+            feedback = QgsProcessingFeedback()
+
         vrt = '<OGRVRTDataSource>'
         if union:
             vrt += '<OGRVRTUnionLayer name="UnionedLayer">'

python/plugins/processing/core/GeoAlgorithm.py

@@ -193,7 +193,7 @@ def processBeforeAddingToModeler(self, alg, model):
 
     # =========================================================
 
-    def execute(self, feedback=QgsProcessingFeedback(), model=None):
+    def execute(self, feedback=None, model=None):
         """The method to use to call a processing algorithm.
 
         Although the body of the algorithm is in processAlgorithm(),
@@ -203,6 +203,10 @@ def execute(self, feedback=QgsProcessingFeedback(), model=None):
         Raises a GeoAlgorithmExecutionException in case anything goes
         wrong.
         """
+
+        if feedback is None:
+            feedback = QgsProcessingFeedback()
+
         self.model = model
         try:
             self.setOutputCRS()

python/plugins/processing/gui/AlgorithmExecutor.py

@@ -48,8 +48,12 @@ def runalg(alg, feedback=None):
     Return true if everything went OK, false if the algorithm
     could not be completed.
     """
+
+    if feedback is None:
+        feedback = QgsProcessingFeedback()
+
     try:
-        alg.execute(feedback or QgsProcessingFeedback())
+        alg.execute(feedback)
         return True
     except GeoAlgorithmExecutionException as e:
         ProcessingLog.addToLog(sys.exc_info()[0], ProcessingLog.LOG_ERROR)