Fix unique values on GPKG pk

elpaso · elpaso · commit 1689c9364b99 · 2019-02-19T14:48:10.000+01:00
Fixes #21311
diff --git a/src/providers/ogr/qgsogrprovider.cpp b/src/providers/ogr/qgsogrprovider.cpp
@@ -3618,7 +3618,15 @@ QSet<QVariant> QgsOgrProvider::uniqueValues( int index, int limit ) const
     return uniqueValues; //not a provider field
   }
 
+
   QByteArray sql = "SELECT DISTINCT " + quotedIdentifier( textEncoding()->fromUnicode( fld.name() ) );
+
+  // GPKG fid
+  if ( mGDALDriverName == QLatin1String( "GPKG" ) && mFirstFieldIsFid && index == 0 )
+  {
+    sql += ", " + quotedIdentifier( textEncoding()->fromUnicode( fld.name() ) ) + " AS fid2";
+  }
+
   sql += " FROM " + quotedIdentifier( mOgrLayer->name() );
 
   if ( !mSubsetString.isEmpty() )
diff --git a/tests/src/python/test_provider_ogr_gpkg.py b/tests/src/python/test_provider_ogr_gpkg.py
@@ -1322,6 +1322,28 @@ def testGeopackageLayerMetadata(self):
         self.assertEqual(vl1.metadata().title(), 'my title')
         self.assertEqual(vl1.metadata().abstract(), 'my desc')
 
+    def testUniqueValuesOnFidColumn(self):
+        """Test regression #21311 OGR provider returns an empty set for GPKG uniqueValues"""
+
+        tmpfile = os.path.join(self.basetestpath, 'testGeopackageUniqueValuesOnFidColumn.gpkg')
+        ds = ogr.GetDriverByName('GPKG').CreateDataSource(tmpfile)
+        lyr = ds.CreateLayer('test', geom_type=ogr.wkbPolygon)
+        lyr.CreateField(ogr.FieldDefn('str_field', ogr.OFTString))
+        f = ogr.Feature(lyr.GetLayerDefn())
+        f.SetGeometry(ogr.CreateGeometryFromWkt('POLYGON ((0 0,0 1,1 1,1 0,0 0))'))
+        f.SetField('str_field', 'one')
+        lyr.CreateFeature(f)
+        f = ogr.Feature(lyr.GetLayerDefn())
+        f.SetGeometry(ogr.CreateGeometryFromWkt('POLYGON ((0 0,0 2,2 2,2 0,0 0))'))
+        f.SetField('str_field', 'two')
+        lyr.CreateFeature(f)
+        f = None
+        ds = None
+        vl1 = QgsVectorLayer('{}'.format(tmpfile) + "|layername=" + "test", 'test', 'ogr')
+        self.assertTrue(vl1.isValid())
+        self.assertEqual(vl1.uniqueValues(0), {1, 2})
+        self.assertEqual(vl1.uniqueValues(1), {'one', 'two'})
+
 
 if __name__ == '__main__':
     unittest.main()
