map.getStyle() after map.setFilter(id, null) returns invalid Style JSON

[NicolasMinghetti]

mapbox-gl-js version 0.41.0:

Steps to Trigger Behavior

1. Add a source and layer to mapboxGL
2. Set the filter of the layer to null
3. map.setStyle(map.getStyle()); throws an error

https://jsbin.com/simifaf/2/edit?html,js,console,output

Expected Behavior

Set a filter to null with map.setFilter() is allowed by mapboxGL #4777
map.setStyle() should allow layers to have filter: null

Actual Behavior

map.setStyle() throws an error if a layer has its filter to null

[anandthakker]

@NicolasMinghetti thanks for reporting this issue, and for including a test case!

It's true that Map#setFilter() accepts null as a way to remove a layer's filter. However, Map#setStyle() (and, similarly, Map#addLayer()) expect layers that conform to the Mapbox GL Style Specification, which doesn't currently allow for filter to be null.

If you want to remove a layer's filter via setStyle, you can do so by omitting the filter: property from the layer (rather than setting it to null or undefined)

[jrd]

But then map.getStyle() should conform to the Mapbox GL Style Specification.
Why getStyle() returns layers with a filter attribute value as null?

You're right, setStyle() is doing the right job, but getStyle() does not.

[anandthakker]

Ah - good point @jrd -- I'll reopen this and change the title to reflect that issue.