[processing] Handle context in processing.run

Fix #15985 (Concave hull)

Author: arnaud-morvan

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

@@ -87,16 +87,18 @@ def processAlgorithm(self, context, feedback):
 
         # Delaunay triangulation from input point layer
         feedback.setProgressText(self.tr('Creating Delaunay triangles...'))
-        delone_triangles = processing.run("qgis:delaunaytriangulation", layer, None)['OUTPUT']
+        delone_triangles = processing.run("qgis:delaunaytriangulation", layer, None, context=context)['OUTPUT']
         delaunay_layer = QgsProcessingUtils.mapLayerFromString(delone_triangles, context)
 
         # Get max edge length from Delaunay triangles
         feedback.setProgressText(self.tr('Computing edges max length...'))
-        features = delaunay_layer.getFeatures()
-        if len(features) == 0:
+
+        features = QgsProcessingUtils.getFeatures(delaunay_layer, context)
+        count = QgsProcessingUtils.featureCount(delaunay_layer, context)
+        if count == 0:
             raise GeoAlgorithmExecutionException(self.tr('No Delaunay triangles created.'))
 
-        counter = 50. / len(features)
+        counter = 50. / count
         lengths = []
         edges = {}
         for feat in features:
@@ -126,14 +128,14 @@ def processAlgorithm(self, context, feedback):
 
         # Dissolve all Delaunay triangles
         feedback.setProgressText(self.tr('Dissolving Delaunay triangles...'))
-        dissolved = processing.run("qgis:dissolve", delaunay_layer,
-                                   True, None, None)['OUTPUT']
+        dissolved = processing.run("qgis:dissolve", delaunay_layer.id(),
+                                   True, None, None, context=context)['OUTPUT']
         dissolved_layer = QgsProcessingUtils.mapLayerFromString(dissolved, context)
 
         # Save result
         feedback.setProgressText(self.tr('Saving data...'))
         feat = QgsFeature()
-        dissolved_layer.getFeatures(QgsFeatureRequest().setFilterFid(0)).nextFeature(feat)
+        QgsProcessingUtils.getFeatures(dissolved_layer, context).nextFeature(feat)
         writer = self.getOutputFromName(self.OUTPUT).getVectorWriter(layer.fields().toList(), QgsWkbTypes.Polygon,
                                                                      layer.crs(), context)
         geom = feat.geometry()

python/plugins/processing/core/GeoAlgorithm.py

@@ -212,8 +212,9 @@ def execute(self, context=None, feedback=None, model=None):
             QgsMessageLog.logMessage('\n'.join(lines), self.tr('Processing'), QgsMessageLog.CRITICAL)
             raise GeoAlgorithmExecutionException(str(e) + self.tr('\nSee log for more details'), lines, e)
 
-    def _checkParameterValuesBeforeExecuting(self):
-        context = dataobjects.createContext()
+    def _checkParameterValuesBeforeExecuting(self, context=None):
+        if context is None:
+            context = dataobjects.createContext()
         for param in self.parameters:
             if isinstance(param, (ParameterRaster, ParameterVector,
                                   ParameterMultipleInput)):
@@ -380,11 +381,12 @@ def resolveDataObjects(self):
                                 break
                     param.setValue(";".join(inputlayers))
 
-    def checkInputCRS(self):
+    def checkInputCRS(self, context=None):
         """It checks that all input layers use the same CRS. If so,
         returns True. False otherwise.
         """
-        context = dataobjects.createContext()
+        if context is None:
+            context = dataobjects.createContext()
         crsList = []
         for param in self.parameters:
             if isinstance(param, (ParameterRaster, ParameterVector, ParameterMultipleInput)):

python/plugins/processing/core/Processing.py

@@ -199,15 +199,21 @@ def runAlgorithm(algOrName, onFinish, *args, **kwargs):
                         return
                     i = i + 1
 
-        msg = alg._checkParameterValuesBeforeExecuting()
+        context = None
+        if kwargs is not None and 'context' in list(kwargs.keys()):
+            context = kwargs["context"]
+        else:
+            context = dataobjects.createContext()
+
+        msg = alg._checkParameterValuesBeforeExecuting(context)
         if msg:
             # fix_print_with_import
             print('Unable to execute algorithm\n' + str(msg))
             QgsMessageLog.logMessage(Processing.tr('Unable to execute algorithm\n{0}').format(msg),
                                      Processing.tr("Processing"))
             return
 
-        if not alg.checkInputCRS():
+        if not alg.checkInputCRS(context):
             print('Warning: Not all input layers use the same CRS.\n' +
                   'This can cause unexpected results.')
             QgsMessageLog.logMessage(
@@ -231,7 +237,6 @@ def runAlgorithm(algOrName, onFinish, *args, **kwargs):
             feedback = kwargs["feedback"]
         elif iface is not None:
             feedback = MessageBarProgress(alg.displayName())
-        context = dataobjects.createContext()
 
         ret = execute(alg, context, feedback)
         if ret:

python/plugins/processing/gui/AlgorithmDialog.py

@@ -146,6 +146,8 @@ def checkExtentCRS(self):
     def accept(self):
         self.settings.setValue("/Processing/dialogBase", self.saveGeometry())
 
+        context = dataobjects.createContext()
+
         checkCRS = ProcessingConfig.getSetting(ProcessingConfig.WARN_UNMATCHING_CRS)
         try:
             self.setParamValues()
@@ -169,7 +171,7 @@ def accept(self):
                                              QMessageBox.No)
                 if reply == QMessageBox.No:
                     return
-            msg = self.alg._checkParameterValuesBeforeExecuting()
+            msg = self.alg._checkParameterValuesBeforeExecuting(context)
             if msg:
                 QMessageBox.warning(
                     self, self.tr('Unable to execute algorithm'), msg)
@@ -199,8 +201,6 @@ def accept(self):
             self.setInfo(
                 self.tr('<b>Algorithm {0} starting...</b>').format(self.alg.displayName()))
 
-            context = dataobjects.createContext()
-
             if self.iterateParam:
                 if executeIterating(self.alg, self.iterateParam, context, self.feedback):
                     self.finish(context)