Decluttering issue with Esri vector tiles

[matthias-ccri]

Hello again!

We're using Esri vector tiles and trying to see English labels. Esri's map renders things well, and I wonder if olms can do the same.

In the Esri World_Basemap_GCS_v2 tileset, there are two properties: _name_global and _name_local, but _name_global isn't always English. And we had declutter: true, so these non-english labels made English labels disappear.

Setting declutter: false shows the English labels, but overlapped, and things are ... well, cluttered ... so it's not ideal.

So I wonder if olms has a setting or fix for this. Esri is somehow hiding the non-english labels and showing the English ones, but I don't know how.

Here's a codesandbox: https://codesandbox.io/s/olms-esri-decluttering-xvqs2

It shows Beijing in the Forbidden City:

• with declutter: true:
  
• with declutter: false
  
• Esri's rendering:
  

So Esri's map hides all non-english labels, but I can't tell how... Inspecting the "Altar of Earth and Harvests" label in the middle shows two points with these properties:

{
    "_label_class": 0,
    "_name_local": "祭坛",
    "_name_global": "祭坛",
    "_minzoom": 0,
    "layer": "Building/label"
}

and

{
    "_label_class": 0,
    "_name_local": "社稷坛",
    "_name_global": "Altar of Earth and Harvests",
    "_minzoom": 0,
    "layer": "Emergency/label"
}

However, Esri renders one and not the other. The style rules don't show anything that might achieve that:

{
            "id": "Building/label/Default",
            "type": "symbol",
            "source": "esri",
            "source-layer": "Building/label",
            "minzoom": 15,
            "layout": {
                "symbol-avoid-edges": true,
                "text-font": [
                    "Arial Regular"
                ],
                "text-size": 10,
                "text-letter-spacing": 0.08,
                "text-max-width": 8,
                "text-field": "{_name_global}",
                "text-padding": 20
            },
            "paint": {
                "text-color": "#666659",
                "text-halo-color": "#FAFAE8",
                "text-halo-width": 0.67
            }
        },

and

{
            "id": "Emergency/label/Default",
            "type": "symbol",
            "source": "esri",
            "source-layer": "Emergency/label",
            "minzoom": 13,
            "layout": {
                "symbol-avoid-edges": true,
                "text-font": [
                    "Arial Regular"
                ],
                "text-size": 10,
                "text-letter-spacing": 0.05,
                "text-max-width": 8,
                "text-field": "{_name_global}"
            },
            "paint": {
                "text-color": "#998973",
                "text-halo-color": "#E8DEBB",
                "text-halo-width": 0.67
            }
        },

You might think maybe they consider a label non-english if both _name_global and _name_local are the same, but that applies to English labels as well, such as this park in Ireland:

{
    "_label_class": 0,
    "_name_local": "Royal Liver Assurance Retail Park",
    "_name_global": "Royal Liver Assurance Retail Park",
    "_minzoom": 0,
    "layer": "Retail/label"
}

The only possibility I can think of is that they inspect the characters in the string, which seems crazy:

if (_name_global === _name_local && hasNonLatinCharacters(_name_global)) {
  // Hide the _name_global label
}

Is there something else that could be causing it?

It's been pretty hard debugging these vector tiles. Any help would be appreciated, including hacks.