[processing] fix handling of optional string arguments (fix #9109, 9120)

Author: alexbruy

python/plugins/processing/gdal/ClipByExtent.py

@@ -60,7 +60,7 @@ def defineCharacteristics(self):
             'none'))
         self.addParameter(ParameterExtent(self.PROJWIN, 'Clipping extent'))
         self.addParameter(ParameterString(self.EXTRA,
-                          'Additional creation parameters', ''))
+                          'Additional creation parameters', '', optional=True))
         self.addOutput(OutputRaster(self.OUTPUT, 'Output layer'))
 
     def processAlgorithm(self, progress):

python/plugins/processing/gdal/ClipByMask.py

@@ -70,7 +70,7 @@ def defineCharacteristics(self):
         self.addParameter(ParameterBoolean(self.KEEP_RESOLUTION,
                           'Keep resolution of output raster', False))
         self.addParameter(ParameterString(self.EXTRA,
-                          'Additional creation parameters', ''))
+                          'Additional creation parameters', '', optional=True))
         self.addOutput(OutputRaster(self.OUTPUT, 'Output layer'))
 
     def processAlgorithm(self, progress):

python/plugins/processing/gdal/contour.py

@@ -64,7 +64,7 @@ def defineCharacteristics(self):
             'Attribute name (if not set, no elevation attribute is attached)',
             'ELEV', optional=True))
         self.addParameter(ParameterString(self.EXTRA,
-                          'Additional creation parameters', ''))
+                          'Additional creation parameters', '', optional=True))
 
         self.addOutput(OutputVector(self.OUTPUT_VECTOR,
                        'Output file for contour lines (vector)'))

python/plugins/processing/gdal/translate.py

@@ -84,7 +84,7 @@ def defineCharacteristics(self):
             'Copy all subdatasets of this file to individual output files',
             False))
         self.addParameter(ParameterString(self.EXTRA,
-                          'Additional creation parameters', ''))
+                          'Additional creation parameters', '', optional=True))
         self.addOutput(OutputRaster(self.OUTPUT, 'Output layer'))
 
     def processAlgorithm(self, progress):

python/plugins/processing/gdal/warp.py

@@ -67,7 +67,7 @@ def defineCharacteristics(self):
         self.addParameter(ParameterSelection(self.METHOD, 'Resampling method',
                           self.METHOD_OPTIONS))
         self.addParameter(ParameterString(self.EXTRA,
-                          'Additional creation parameters', ''))
+                          'Additional creation parameters', '', optional=True))
         self.addOutput(OutputRaster(self.OUTPUT, 'Output layer'))
 
     def processAlgorithm(self, progress):

python/plugins/processing/modeler/ModelerParametersDialog.py

@@ -745,8 +745,8 @@ def setParamStringValue(self, param, widget):
             else:
                 self.params[param.name] = value
         else:
-            if widget.currentText() == '':
-                return False
+            #if widget.currentText() == '':
+            #    return False
             idx = widget.findText(widget.currentText())
             if idx < 0:
                 name = self.getSafeNameForHarcodedParameter(param)

python/plugins/processing/parameters/ParameterString.py

@@ -43,6 +43,9 @@ def __init__(self, name='', description='', default='', multiline=False,
 
     def setValue(self, obj):
         if obj is None:
+            if self.optional:
+                self.value = ''
+                return True
             self.value = self.default
             return True
         self.value = unicode(obj).replace(ParameterString.ESCAPED_NEWLINE,