[vectortiles] Never trust internal feature ids

Even if a feature has an internal ID, it's not guaranteed to be unique across different tiles. This may violate the specifications, but it's been seen on mbtiles files in the wild... Here the consequences of a reused id (including missing feature labels) is worse then the consequence of ignoring valid internal feature ids (which probably has no real consequence at all...) (cherry picked from commit 70aea49)
qgis · Jan 15, 2021 · 7e4cdf4 · 7e4cdf4
1 parent 2d9c96c
commit 7e4cdf4
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/src/core/vectortile/qgsvectortilemvtdecoder.cpp b/src/core/vectortile/qgsvectortilemvtdecoder.cpp
@@ -115,9 +115,13 @@ QgsVectorTileFeatures QgsVectorTileMVTDecoder::layerFeatures( const QMap<QString
       const ::vector_tile::Tile_Feature &feature = layer.features( featureNum );
 
       QgsFeatureId fid;
+#if 0
+      // even if a feature has an internal ID, it's not guaranteed to be unique across different
+      // tiles. This may violate the specifications, but it's been seen on mbtiles files in the wild...
       if ( feature.has_id() )
         fid = static_cast<QgsFeatureId>( feature.id() );
       else
+#endif
       {
         // There is no assigned ID, but some parts of QGIS do not work correctly if all IDs are zero
         // (e.g. labeling will not register two features with the same FID within a single layer),