[Processing] Improve the robustness of models when the parameters in the included algorithms change

Author: radosuav

python/plugins/processing/modeler/ModelerAlgorithm.py

@@ -35,6 +35,8 @@
 from PyQt4.QtCore import QCoreApplication, QPointF
 from PyQt4.QtGui import QIcon
 from qgis.core import QgsRasterLayer, QgsVectorLayer
+from qgis.gui import QgsMessageBar
+from qgis.utils import iface
 from processing.core.GeoAlgorithm import GeoAlgorithm
 from processing.modeler.WrongModelException import WrongModelException
 from processing.core.GeoAlgorithmExecutionException import GeoAlgorithmExecutionException
@@ -332,7 +334,13 @@ def prepareAlgorithm(self, alg):
         algInstance = alg.algorithm
         for param in algInstance.parameters:
             if not param.hidden:
-                value = self.resolveValue(alg.params[param.name])
+                if param.name in alg.params:
+                    value = self.resolveValue(alg.params[param.name])
+                else:
+                    iface.messageBar().pushMessage(self.tr("Warning"),
+                                                   self.tr("Parameter %s in algorithm %s in the model is run with default value! Edit the model to make sure that this is correct." % (param.name, alg.name)), 
+                                                   QgsMessageBar.WARNING, 4)
+                    value = None
                 if value is None and isinstance(param, ParameterExtent):
                     value = self.getMinCoveringExtent()
                 # We allow unexistent filepaths, since that allows

python/plugins/processing/modeler/ModelerParametersDialog.py

@@ -410,7 +410,10 @@ def setPreviousValues(self):
                 if param.hidden:
                     continue
                 widget = self.valueItems[param.name]
-                value = alg.params[param.name]
+                if param.name in alg.params:
+                    value = alg.params[param.name]
+                else:
+                    value = None
                 if isinstance(param, (
                         ParameterRaster,
                         ParameterVector,

python/plugins/processing/modeler/ModelerScene.py

@@ -98,7 +98,10 @@ def paintModel(self, model):
             idx = 0
             for parameter in alg.algorithm.parameters:
                 if not parameter.hidden:
-                    value = alg.params[parameter.name]
+                    if parameter.name in alg.params:
+                        value = alg.params[parameter.name]
+                    else:
+                        value = None
                     sourceItems = self.getItemsFromParamValue(value)
                     for sourceItem, sourceIdx in sourceItems:
                         arrow = ModelerArrowItem(sourceItem, sourceIdx, self.algItems[alg.name], idx)