diff --git a/python/plugins/processing/algs/gdal/GdalAlgorithmDialog.py b/python/plugins/processing/algs/gdal/GdalAlgorithmDialog.py
index ce56c8205d5..8575ec8cb9a 100644
--- a/python/plugins/processing/algs/gdal/GdalAlgorithmDialog.py
+++ b/python/plugins/processing/algs/gdal/GdalAlgorithmDialog.py
@@ -37,6 +37,7 @@ from qgis.PyQt.QtWidgets import (QWidget,
                                  QSizePolicy,
                                  QDialogButtonBox)
 
+from qgis.core import QgsProcessingFeedback
 from qgis.gui import QgsMessageBar
 
 from processing.gui.AlgorithmDialog import AlgorithmDialog
@@ -44,6 +45,7 @@ from processing.gui.AlgorithmDialogBase import AlgorithmDialogBase
 from processing.gui.ParametersPanel import ParametersPanel
 from processing.gui.MultipleInputPanel import MultipleInputPanel
 from processing.gui.NumberInputPanel import NumberInputPanel
+from processing.tools.dataobjects import createContext
 
 
 class GdalAlgorithmDialog(AlgorithmDialog):
@@ -102,15 +104,15 @@ class GdalParametersPanel(ParametersPanel):
                 w.hasChanged.connect(self.parametersHaveChanged)
 
     def parametersHaveChanged(self):
+        context = createContext()
+        feedback = QgsProcessingFeedback()
         try:
             parameters = self.parent.getParamValues()
             for output in self.alg.destinationParameterDefinitions():
-                if parameters[output.name()] is None:
+                if not output.name() in parameters or parameters[output.name()] is None:
                     parameters[output.name()] = self.tr("[temporary file]")
-            commands = self.alg.getConsoleCommands(parameters)
+            commands = self.alg.getConsoleCommands(parameters, context, feedback)
             commands = [c for c in commands if c not in ['cmd.exe', '/C ']]
             self.text.setPlainText(" ".join(commands))
         except AlgorithmDialogBase.InvalidParameterValue as e:
             self.text.setPlainText(self.tr("Invalid value for parameter '{0}'").format(e.parameter.description()))
-        except:
-            self.text.setPlainText("")
diff --git a/python/plugins/processing/algs/gdal/GdalUtils.py b/python/plugins/processing/algs/gdal/GdalUtils.py
index 053efe6015b..f5e5923ca7a 100755
--- a/python/plugins/processing/algs/gdal/GdalUtils.py
+++ b/python/plugins/processing/algs/gdal/GdalUtils.py
@@ -198,7 +198,8 @@ class GdalUtils(object):
                           + '"'
             else:
                 escaped = s
-            joined += escaped + ' '
+            if escaped is not None:
+                joined += escaped + ' '
         return joined.strip()
 
     @staticmethod
@@ -245,7 +246,7 @@ class GdalUtils(object):
         if layer is None:
             path, ext = os.path.splitext(uri)
             format = QgsVectorFileWriter.driverForExtension(ext)
-            return '"' + uri + '"', format
+            return '"' + uri + '"', '"' + format + '"'
 
         provider = layer.dataProvider().name()
         if provider == 'spatialite':
@@ -317,7 +318,7 @@ class GdalUtils(object):
             path, ext = os.path.splitext(ogrstr)
             format = QgsVectorFileWriter.driverForExtension(ext)
 
-        return '"' + ogrstr + '"', format
+        return '"' + ogrstr + '"', '"' + format + '"'
 
     @staticmethod
     def ogrLayerName(uri):
diff --git a/python/plugins/processing/gui/AlgorithmDialog.py b/python/plugins/processing/gui/AlgorithmDialog.py
index 3b9a32ea30d..9d21a1fd6ad 100644
--- a/python/plugins/processing/gui/AlgorithmDialog.py
+++ b/python/plugins/processing/gui/AlgorithmDialog.py
@@ -93,6 +93,9 @@ class AlgorithmDialog(AlgorithmDialogBase):
     def getParamValues(self):
         parameters = {}
 
+        if not hasattr(self, 'mainWidget') or self.mainWidget is None:
+            return parameters
+
         for param in self.alg.parameterDefinitions():
             if param.flags() & QgsProcessingParameterDefinition.FlagHidden:
                 continue