[processing] Fix crash when algorithms fail to prepare

Refs #15640
qgis · Feb 25, 2018 · 2900ace · 2900ace
1 parent 574a654
commit 2900ace
Show file tree

Hide file tree

Showing 2 changed files with 6 additions and 1 deletion.
diff --git a/python/plugins/processing/algs/qgis/FieldsMapper.py b/python/plugins/processing/algs/qgis/FieldsMapper.py
@@ -138,10 +138,11 @@ def prepareAlgorithm(self, parameters, context, feedback):
             expression.setDistanceUnits(context.project().distanceUnits())
             expression.setAreaUnits(context.project().areaUnits())
             if expression.hasParserError():
-                raise QgsProcessingException(
+                feedback.reportError(
                     self.tr(u'Parser error in expression "{}": {}')
                     .format(expression.expression(),
                             expression.parserErrorString()))
+                return False
             self.expressions.append(expression)
         return True
 

diff --git a/src/core/processing/qgsprocessingalgrunnertask.cpp b/src/core/processing/qgsprocessingalgrunnertask.cpp
@@ -41,10 +41,14 @@ QgsProcessingAlgRunnerTask::QgsProcessingAlgRunnerTask( const QgsProcessingAlgor
 void QgsProcessingAlgRunnerTask::cancel()
 {
   mFeedback->cancel();
+  QgsTask::cancel();
 }
 
 bool QgsProcessingAlgRunnerTask::run()
 {
+  if ( isCanceled() )
+    return false;
+
   connect( mFeedback, &QgsFeedback::progressChanged, this, &QgsProcessingAlgRunnerTask::setProgress );
   bool ok = false;
   try