QGIS » QGIS Application

When buffering ('DISSOLVE':True) a valid GeoPackage Pointlayer and choosing a distance small enough for the resulting bufferlayer to have multiple parts, the resulting GeoPackage Layer (saved in the same GeoPackage) will be of Geometry Type Polygon (where it should be Multipolygon).

Problems with the resulting Layer
- The Layer (or parts of it) are dissappearing when zooming in
- The Layer cannot be used for e.g. spatial selections etc.
- qgis:checkvalidity (with GEOS) shows the whole layer as invalid
- DBManager (or copying the Geometry) shows Geometry Type Polygon (NOT Multipolygon) despite having multiple parts but only one row in the Attribute Table

Executing the fix geometry tool ("native:fixgeometries") and saving the result in the same GeoPackage results in a perfectly fine (Multipolygon)-layer.

From the history window:

processing.run("native:buffer", {'INPUT':'C:/data/bufferbug.gpkg|layername=inputpoints','DISTANCE':200,'SEGMENTS':5,'END_CAP_STYLE':0,'JOIN_STYLE':0,'MITER_LIMIT':2,'DISSOLVE':True,'OUTPUT':'ogr:dbname=\'C:/data/bufferbug.gpkg\' table=\"buffer_200m\" (geom) sql='})

processing.run("qgis:checkvalidity", {'INPUT_LAYER':'C:/data/bufferbug.gpkg|layername=buffer_200m','METHOD':2,'VALID_OUTPUT':'memory:','INVALID_OUTPUT':'memory:','ERROR_OUTPUT':'memory:'})

To reproduce the bug:
- buffer the inputpoints layer in the attached GeoPackage with 200 Meters (with everything dissolved - see processing.run from above)
(The Geopackage also includes...
- the invalid Bufferresult (buffer_200m)
- the repaired (by using "native:fixgeometries") and now valid layer (repariert)