[iOS] Predicate "extrude == true" does not correctly filter results

[jmkiley]

Platform: iOS
Mapbox SDK version: v3.6.0-alpha.1

The documentation for MGLFillExtrusionStyleLayer currently suggests that developers use the following predicate:

layer.predicate = NSPredicate(format: "extrude == TRUE")

However, this does not work. I have tested it out with different capitalizations as well. In order to correctly filter buildings/building parts, the predicate should be:
layer.predicate = NSPredicate(format: "extrude == %@ AND height >= 0", "true")

Is this is intended behavior, or is just correcting the documentation will be enough.

cc @1ec5 @incanus @boundsj

[1ec5]

It turns out that the extrude property in the Mapbox Streets v7 source is a string (either "true" or "false") rather than a Boolean value. (That isn’t apparent from the source documentation.) So MGLFillExtrusionStyleLayer’s documentation should be updated to use the format string extrude == 'true' rather than extrude == TRUE.

/cc @ajashton

[1ec5]

Fixed in #9059 on the release-ios-v3.6.0-android-v5.1.0 branch.