QGIS » QGIS Application

Tested on QGIS master and with this https://github.com/qgis/QGIS/pull/5099 patched version of Processing (that backports some fixes/enhancements from master).

As sample project/dataset it can be used the first one contained here

https://issues.qgis.org/attachments/download/11399/union_intersection_test_datasets.zip

running tools (tested union and intersection) with the "AreaA" and "areaB" inputs (that have some geometry issues, auto-intersections) then on master the following is thrown:

Algorithm 'Union' starting...
Input parameters: {'INPUT': <QgsProcessingFeatureSourceDefinition {'source':AreaA20170911213135765, 'selectedFeaturesOnly': False}

, 'OUTPUT': <QgsProcessingOutputLayerDefinition {'sink':memory:, 'createOptions': {'fileEncoding': 'System'}}>, 'OVERLAY': <QgsProcessingFeatureSourceDefinition

{'source':AreaB20170911213135757, 'selectedFeaturesOnly': False}

}

Traceback (most recent call last): File "C:/OSGEO4~1/apps/qgis-dev/./python/plugins\processing\algs\qgis\Union.py", line 101, in processAlgorithm indexB = QgsSpatialIndex(sourceB.getFeatures(QgsFeatureRequest().setSubsetOfAttributes([]).setDestinationCrs(sourceA.sourceCrs())), feedback) Exception: unknown
Execution failed after 0.04 seconds

on 2.18.12 the intersection operation is blocked with a clear message

GEOS geoprocessing error: One or more input features have invalid geometry.

while the union it is not (not even a message in the log), and a wrong results is produced and added to the project.