Add note about throwing QgsProcessingException to cancel algorithm execution

nyalldawson · nyalldawson · commit c2cad99d6b18 · 2017-07-18T19:44:33.000+10:00
diff --git a/python/core/processing/qgsprocessingalgorithm.sip b/python/core/processing/qgsprocessingalgorithm.sip
@@ -833,6 +833,11 @@ class QgsProcessingFeatureBasedAlgorithm : QgsProcessingAlgorithm
  The provided ``feedback`` object can be used to push messages to the log and for giving feedback
  to users. Note that handling of progress reports and algorithm cancelation is handled by
  the base class and subclasses do not need to reimplement this logic.
+
+ Algorithms can throw a QgsProcessingException if a fatal error occurred which should
+ prevent the algorithm execution from continuing. This can be annoying for users though as it
+ can break valid model execution - so use with extreme caution, and consider using
+ ``feedback`` to instead report non-fatal processing failures for features instead.
  :rtype: bool
 %End
 
diff --git a/src/core/processing/qgsprocessingalgorithm.h b/src/core/processing/qgsprocessingalgorithm.h
@@ -804,6 +804,11 @@ class CORE_EXPORT QgsProcessingFeatureBasedAlgorithm : public QgsProcessingAlgor
      * The provided \a feedback object can be used to push messages to the log and for giving feedback
      * to users. Note that handling of progress reports and algorithm cancelation is handled by
      * the base class and subclasses do not need to reimplement this logic.
+     *
+     * Algorithms can throw a QgsProcessingException if a fatal error occurred which should
+     * prevent the algorithm execution from continuing. This can be annoying for users though as it
+     * can break valid model execution - so use with extreme caution, and consider using
+     * \a feedback to instead report non-fatal processing failures for features instead.
      */
     virtual bool processFeature( QgsFeature &feature, QgsProcessingFeedback *feedback ) = 0;
 
