*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__SwiftValue objCType]: unrecognized selector sent to instance

[pappalar]

*** First throw call stack:
(
	0   CoreFoundation                      0x000000010fe5c6fb __exceptionPreprocess + 331
	1   libobjc.A.dylib                     0x000000010e383ac5 objc_exception_throw + 48
	2   CoreFoundation                      0x000000010fe7aab4 -[NSObject(NSObject) doesNotRecognizeSelector:] + 132
	3   CoreFoundation                      0x000000010fe61443 ___forwarding___ + 1443
	4   CoreFoundation                      0x000000010fe63238 _CF_forwarding_prep_0 + 120
	5   Mapbox                              0x0000000109d383ab -[NSExpression(MGLPrivateAdditions) mgl_constantMBGLValue] + 861
	6   Mapbox                              0x0000000109d2da9b -[NSDictionary(MGLAdditions) mgl_propertyMap] + 771
	7   Mapbox                              0x0000000109c9fabc _Z11mbglFeatureN6mapbox7feature7featureIdEEP11objc_objectP12NSDictionary + 214
	8   Mapbox                              0x0000000109ca1913 -[MGLPointFeature geoJSONObject] + 177
	9   Mapbox                              0x0000000109ca650e -[MGLShapeCollectionFeature geoJSONObject] + 430
	10  Mapbox                              0x0000000109cb6f0e -[MGLShapeSource setShape:] + 88

Steps to reproduce

1. Create a Swift Class that inherits from MGLPolylineFeature
2. Add a instance of this class to a a collection Feature: MGLShapeCollectionFeature(shapes: [yourInstance])
3. Add this shape to one of your MGLShapeSource sources

Expected behavior

Mapbox uses the subclass of MGLPolylineFeature on the map

Actual behavior

App Crashes due to uncaught exception 'NSInvalidArgumentException', reason: '-[__SwiftValue objCType]: unrecognized selector sent to instance

Question:

Is it possible to subclass Style Primitives?

Notice: Same issue happens with subclasses of MGLPointFeature

Mapbox SDK versions: 5.0.0

[pappalar]

On a secondary note.

Being MGLPolylineFeature a interface of protocol MGLFeature
is impossible from subclasses to call super.init(coordinates: coordinates, count: UInt(geometry.count)) as the initializer is not a designated one for the superclass

[1ec5]

The code that serializes the MGLPolylineFeature into GeoJSON is tripping over some Swift object in the attributes dictionary that has been cast into an NSValue but isn’t one, likely a Swift struct or enumeration. This document lists the types that are supported in attributes.

Being MGLPolylineFeature a interface of protocol MGLFeature
is impossible from subclasses to call super.init(coordinates: coordinates, count: UInt(geometry.count)) as the initializer is not a designated one for the superclass

Can you speak to why you’re trying to subclass MGLPolylineFeature? If you use an MGLFeature in a shape source, the original object gets lost anyways and you won’t be able to take advantage of your subclass when using runtime styling or feature querying.

[pappalar]

It seems to me that the original issue was with a private struct shadowing another subclass struct.
I am using struct to wrap static let keys (attributes string keys).
After some reshaping of the struct I managed to get rid of the exception.

@1ec5 to the reason why:

I need to display a quite large amount of different features, each one with its own attributes used in the style for the rendering.
I later on need to interact on the map with those features and I would rather know which type of data I am passing around the app.

To simplify my life I am doing the following:

• I created different subclasses of a concrete implementation of MGLFeature (eg: Polyline) that have a convenience initializers for my own different needs.
• Internally each subclass is not storing any additional properties but configuring all rendering data in the attributes + storing any additional value I might need later also as an attribute.
• The same subclass has an additional initializer that takes a MGLFeature (the one I read from the map) and internally copies over the attributes and coordinates.

This way when I interact with the map I can filter by layer, knowing then which subclass I am interacting with, create back the subclass and use computed properties to access all the attributes without the need to know which keys are used (as I have many and need the object across different part of the app)

This approach works for PointFeatures, as there is no convenience initializer for MGLPointAnnotation

so doing the following in a subclass works:

self.init()
self.coordinate = coordinate

However is currently failing for me for Polylines:

as I cant call the initializer MGLPolylineFeature(coordinates: coordinates, count: UInt(geometry.count)) in a subclass I am forced to do

super.init() // NSObject init??
self.appendCoordinates(coordinates, count: UInt(geometry.count))

which does not initialize correctly the Polyline and does not display it on the map.

There is any way I can initialize correctly a subclass of MGLPolylineFeature?

[pappalar]

After trying all other possibilities and reading the source code I noticed that

super.init() // NSObject init??
self.setCoordinates(coordinates, count: UInt(geometry.count))

seems to be working as expected.

I think the reported things above will change in case #7454 somehow restructures things out