Not all relations accepted in `relation_scan_function` are passed to `relation_function`

[FireFragment]

Lot of boundary relations in Prague with admin_level=10 (such as relation 428369) are not passed to the relation_function. What is interesting is that they ARE passed to the relation_scan_function and are successfully accepted. They are also readable inside way_function. Also, some of the relations (such as relation 435882) work correctly, despite being very similiar to the problematic ones.

The simplest way to reproduce is:

1. Download https://download.geofabrik.de/europe/czech-republic-latest.osm.pbf

2. Create process.lua and config.json files:

process.lua:

relation_id = "428369"

function relation_scan_function()
    if Id() == relation_id then
        print("Found the relation in relation_scan_function")
        Accept()
    end
end
-- Assign ways to a layer, and set attributes, based on OSM tags
function relation_function()
    if Id() == relation_id then
        print("Found the relation in relation_function")
        Layer("boundary", true)
    end
end

function way_function()
end

function node_function()
end

config.json:

{
	"layers": {
	    "boundary": { "minzoom":  8, "maxzoom": 8 }
	},
	"settings": {
		"minzoom": 8,
		"maxzoom": 8,
		"basezoom": 8,
		"include_ids": true,
		"name": "Error reproduction",
		"version": "0.1",
		"description": "Error reproduction",
		"compress": "gzip"
	}
}

3. Run tilemaker on theese files:

    tilemaker osm-data.pbf tiles.pmtiles --process process.lua --config config.json
   

After that, you can see that Found the relation in relation_scan_function is present in tilemaker's logs as expected, however Found the relation in relation_function is missing. The relation is also mising from the produced tileset.

When you replace relation_id = "428369" with relation_id = "435882" it starts working correctly, printing both Found the relation in relation_scan_function and Found the relation in relation_function, despite these being very similar relations.

---

When running tilemaker with a different lua code which accepts all relations with admin_level=10...

See the code

function relation_scan_function()
    if Find("type")=="boundary" and Find("admin_level")=="10" then
        Accept()
    end
end
-- Assign ways to a layer, and set attributes, based on OSM tags
function relation_function()
    if Find("type")=="boundary" and Find("admin_level")=="10" then
        Layer("boundary",true)
    end
end

function way_function()
end

function node_function()
end

...it produces tiles looking like this when viewed on https://pmtiles.io (this is relation 435882 , you can see that it's there without any surrounding boundaries. There are some other relations outside of bounds of the screenshot).

.

However when running the equivalent overpass query, we can see that there are in fact many more relations which are missing from generated tiles: