Runtime styling sometimes doesn't take effect

[kkaefer]

When using a GeoJSON source, and setting runtime styling properties, then updating the GeoJSON source data, the changes to the style don't always take effect.

https://jsfiddle.net/ygxuk5zy/ contains a reduced test case (replace your access token). This is how it should look:

This is how it actually looks:

[anandthakker]

Ah - the problem here is that map.getLayer().setPaintProperty() is not intended to be a user-facing method. In fact, that's true of all the methods of the StyleLayer class; I think map.getLayer() should really be returning a serialized copy of the layer -- I will ticket this separately.

Replacing map.getLayer('route').setPaintProperty('line-width', 5) with map.setPaintProperty('route', 'line-width', 5) fixes the fiddle.

[jfirebaugh]

There's an actual bug here too, however. Consider the following execution sequence:

Main	Worker
geoJSONSource.setData(new);
sends geojson.loadData message
setPaintProperty(layer, prop, new); (using DDS)
	receives geojson.loadData message
	performs indexing
	sends response
receives response
sends reloadTile message

And then the following (in independent relative ordering):

Main	Worker
🎉 animation frame 🎉	receives reloadTile message
style.update(...)	parses the tile using new data but old property definition 💣
broadcast updateLayers
send reloadTile (due to the DDS property change)

If the old property definition depended on attributes that aren't present in the new data -- for example, if the property value is a categorical source function where the source domain values are unique feature IDs -- then the result will fall back to default values (e.g. black color).

[jfirebaugh]

@anandthakker Can you take a look at this? I am finding it difficult to see any easy fix without large scale refactoring (#2291, #4875), so that #3692 is feasible.

[anandthakker]

@jfirebaugh until we can take on the necessary refactoring to solve the problem more systematically, a temporary measure to patch this would be to expose something like SourceCache#{pause,resume}(). The Style could use this to prevent tiles from being (re)loaded between the call to a runtime-styling method and the subsequent animation frame => updateLayers broadcast.