[OGR provider] GPKG: allow repeated creation of int fields with len != 0 (fixes #19009)

rouault · rouault · commit f4bf1ec90709 · 2018-06-01T13:15:41.000+02:00
diff --git a/src/providers/ogr/qgsogrprovider.cpp b/src/providers/ogr/qgsogrprovider.cpp
@@ -1557,6 +1557,10 @@ bool QgsOgrProvider::addAttributes( const QList<QgsField> &attributes )
       returnvalue = false;
     }
   }
+
+  // Backup existing fields. We need them to 'restore' field type, length, precision
+  QgsFields oldFields = mAttributeFields;
+
   loadFields();
 
   // The check in QgsVectorLayerEditBuffer::commitChanges() is questionable with
@@ -1578,6 +1582,24 @@ bool QgsOgrProvider::addAttributes( const QList<QgsField> &attributes )
     }
   }
 
+  // Restore field type, length, precision of existing fields as well
+  // We need that in scenarios where the user adds a int field with length != 0
+  // in a editing session, and repeat that again in another editing session
+  // Without the below hack, the length of the first added field would have
+  // been reset to zero, and QgsVectorLayerEditBuffer::commitChanges() would
+  // error out because of this.
+  // See https://issues.qgis.org/issues/19009
+  for ( auto field : oldFields )
+  {
+    int idx = mAttributeFields.lookupField( field.name() );
+    if ( idx >= 0 )
+    {
+      mAttributeFields[ idx ].setType( field.type() );
+      mAttributeFields[ idx ].setLength( field.length() );
+      mAttributeFields[ idx ].setPrecision( field.precision() );
+    }
+  }
+
   return returnvalue;
 }
 
diff --git a/tests/src/python/test_provider_ogr_gpkg.py b/tests/src/python/test_provider_ogr_gpkg.py
@@ -929,6 +929,26 @@ def testRequestWithoutGeometryOnLayerMixedGeometry(self):
         features = [f for f in vl.getFeatures(request)]
         self.assertEqual(len(features), 1)
 
+    def testAddingTwoIntFieldsWithWidth(self):
+        """ Test buggfix for https://issues.qgis.org/issues/19009 """
+
+        tmpfile = os.path.join(self.basetestpath, 'testRequestWithoutGeometryOnLayerMixedGeometry.gpkg')
+        ds = ogr.GetDriverByName('GPKG').CreateDataSource(tmpfile)
+        lyr = ds.CreateLayer('test', geom_type=ogr.wkbPoint, options=['SPATIAL_INDEX=NO'])
+        lyr.CreateField(ogr.FieldDefn('a', ogr.OFTInteger))
+        ds = None
+
+        vl = QgsVectorLayer(u'{}'.format(tmpfile) + "|layername=" + "test", 'test', u'ogr')
+        self.assertTrue(vl.isValid())
+
+        vl.startEditing()
+        self.assertTrue(vl.addAttribute(QgsField("b", QVariant.Int, "integer", 10)))
+        self.assertTrue(vl.commitChanges())
+
+        vl.startEditing()
+        self.assertTrue(vl.addAttribute(QgsField("c", QVariant.Int, "integer", 10)))
+        self.assertTrue(vl.commitChanges())
+
 
 if __name__ == '__main__':
     unittest.main()
