Upgraded region maps display Error downloading vector data error

[bhavyarm]

Kibana version: 6.8.13->7.10.0

Elasticsearch version: 6.8.13->7.10.0

Server OS version: darwin_x86_64

Browser version: chrome latest

Browser OS version: OS X

Original install method (e.g. download page, yum, from source, etc.): from staging

Describe the bug: I performed a rolling upgrade from 6.8.13 to 7.10.0 and Kibana displays the following error on the dashboard with this region map.

The data is on logstash index pattern from here: https://www.elastic.co/guide/en/kibana/6.8/tutorial-load-dataset.html

Please note this doesn't happen on new region map which I created after enabling

xpack.maps.showMapVisualizationTypes: true

Error downloading vector data

Cannot download World Countries file. Please ensure the CORS configuration of the server permits requests from the Kibana application on this host.

Screenshots (if relevant):

This is the exported saved object of the dashboard with related objects -
export (16).ndjson.txt

[elasticmachine]

Pinging @elastic/kibana-gis (Team:Geo)

[jsanz]

I could reproduce. After upgrading from 6.8 to 7.10 and opening the region map, the new World Countries dataset is requested (the new TopoJSON dataset) and correctly retrieved, but for some reason it's not being processed

I could also see this error in the console

So it looks like the visualization is understanding the boundaries as a GeoJSON dataset instead of a TopoJSON.

[thomasneirynck]

Does this also occur when upgrading from 7.9 to 7.10?

[bhavyarm]

@thomasneirynck @LeeDr same bug while upgrading from 7.9.3 ->7.10.0

[thomasneirynck]

thx @bhavyarm for confirming. I will investigate on Kibana end.

[nickpeihl]

I think this is the offending line. https://github.com/elastic/kibana/blob/master/src/plugins/maps_legacy/public/map/service_settings.js#L234

If the choropleth_layer expects a geojson format we should not return the defaultFormat.

[thomasneirynck]

@jsanz that error #82539 (comment) was probably introduced here: #78027