Enable multi-layer GetMap, GetFeatureInfo to return text/mapml structured to request multi-layer vector tiles about geoserver HOT 2 OPEN

Just a clarification for the case "mapmlmultiextent: false; mapmlusefeatures:true; mapmlusetiles:true", specifically for the situation where multiple layers have been requested (not a single layer group).
In this case, one cannot use WMTS, even if each single layer is cached, because the protocol only allows one tile at a time, one cannot ask for a list of layers. This forces falling back to tiled WMS.

However, if the request is a group, and the group is tile cached, then yes, it can be handled as a single WMTS request instead.

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However, if the request is a group, and the group is tile cached, then yes, it can be handled as a single WMTS request instead.

Say a request comes in as follows: request=GetMap&format_options=mapmlmultiextent: false; mapmlusefeatures:true; mapmlusetiles:true&layers=a,b,c (your scenario above, basically)

where b is a layer group. I believe that I've specified that b should be de-nested and rendered as features within the one tile in order in the a,b,c stack, just as it would be if it was being rendered to a bitmap in a traditional WMS request (that was being cached as a tile).

What I wrote above for this situation is:

create singleton map-extent
if no tile cache
-> use tile-shaped GetMap as URL template
-> rel=tile type=text/mapml
-> URL template contains mapmlfeatures:true
-> generate rel=query map-link over WMS GetFeatureInfo, infoformat=text/mapml
else
-> use GetTile for text/mapml
-> generate rel=query map-link over WMTS GetFeatureInfo, infoformat=text/mapml

The map-extent would be generated to create 'tile-shaped GetMap requests'

<map-link rel=tile type=text/mapml tref="...GetMap&layers=a,b,c&format_options:mapmlfeatures:true...">

but I see that there is an 'else' above that says to use GetTile and I believe that is your concern. I think I could clarify that with further logic to clarify that using GetTile is only possible in the single-layer case. Am I correct, that's what you're saying?

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