[Android] removeSource no longer (6.0.0+) safe when source does not exist

[rm3dbeckers]

Platform: Android
Mapbox SDK version: 6.0.1

Steps to trigger behavior

1. call MapboxMap.removeSource(String sourceID) with a sourceID that has not been added.

Expected behavior

The call should succeed and return null.

Actual behavior

The call throws an NPE.

NativeMapView.java will perform the following:

  @Nullable
  public Source removeSource(@NonNull String sourceId) {
    if (isDestroyedOn("removeSource")) {
      return null;
    }
    Source source = getSource(sourceId);
    return removeSource(source);
  }

getSource(sourceId) will correctly return a null Source but the following removeSource(source) call expects a non-null Source and causes an NPE when trying to get the NativePtr:

  public Source removeSource(@NonNull Source source) {
    if (isDestroyedOn("removeSource")) {
      return null;
    }
    nativeRemoveSource(source, source.getNativePtr());
    return source;
  }

This worked correctly on 5.5.2.

[LukasPaczos]

Good catch, thanks @rm3dbeckers.