[ios, macos] Allow creation of shape collections with no shapes (#7632)

platform/darwin/src/MGLShapeCollection.h

@@ -7,7 +7,7 @@
 NS_ASSUME_NONNULL_BEGIN
 
 /**
- An `MGLShapeCollection` object represents a shape consisting of one or more
+ An `MGLShapeCollection` object represents a shape consisting of zero or more
  distinct but related shapes that are instances of `MGLShape`. The constituent
  shapes can be a mixture of different kinds of shapes.
  

platform/darwin/src/MGLShapeCollection.mm

@@ -12,7 +12,6 @@
 
 - (instancetype)initWithShapes:(NS_ARRAY_OF(MGLShape *) *)shapes {
     if (self = [super init]) {
-        NSAssert(shapes.count, @"Cannot create an empty shape collection");
         _shapes = shapes.copy;
     }
     return self;

platform/darwin/test/MGLFeatureTests.mm

@@ -322,6 +322,15 @@
                                                                              @[@(coord2.longitude), @(coord2.latitude)]]}
                                                        ]};
     XCTAssertEqualObjects(geoJSONFeature[@"geometry"], expectedGeometry);
+
+    // When the shape collection is created with an empty array of shapes
+    shapeCollectionFeature = [MGLShapeCollectionFeature shapeCollectionWithShapes:@[]];
+
+    // it has the correct (empty) geometry
+    geoJSONFeature = [shapeCollectionFeature geoJSONDictionary];
+    expectedGeometry = @{@"type": @"GeometryCollection",
+                         @"geometries": @[]};
+    XCTAssertEqualObjects(geoJSONFeature[@"geometry"], expectedGeometry);
 }
 
 @end

platform/ios/CHANGELOG.md

@@ -63,6 +63,7 @@ Mapbox welcomes participation and contributions from everyone. Please read [CONT
 * Fixed an issue that caused an annotation view to disappear if it isn’t created using the annotation view reuse queue. ([#6485](https://github.com/mapbox/mapbox-gl-native/pull/6485))
 * Fixed an issue that could reset user-added transformations on annotation views. ([#6166](https://github.com/mapbox/mapbox-gl-native/pull/6166))
 * Improved the performance of relocating a non-view-backed point annotation by changing its `coordinate` property. ([#5385](https://github.com/mapbox/mapbox-gl-native/pull/5385))
+* Fixed an issue that caused an assertion failure if a `MGLShapeCollection` (a GeoJSON GeometryCollection) was created with an empty array of shapes. ([#7632](https://github.com/mapbox/mapbox-gl-native/pull/7632))
 * Improved the precision of annotations at zoom levels greater than 18. ([#5517](https://github.com/mapbox/mapbox-gl-native/pull/5517))
 
 ### Networking and offline maps

platform/macos/CHANGELOG.md

@@ -43,6 +43,7 @@ This version of the Mapbox macOS SDK corresponds to version 3.4.0 of the Mapbox
 * Various method arguments that are represented as C arrays of `CLLocationCoordinate2D` instances have been marked `const` to streamline bridging to Swift. ([#7215](https://github.com/mapbox/mapbox-gl-native/pull/7215))
 * To make an MGLPolyline or MGLPolygon span the antimeridian, specify coordinates with longitudes greater than 180° or less than −180°. ([#6088](https://github.com/mapbox/mapbox-gl-native/pull/6088))
 * Fixed an issue where placing a point annotation on Null Island also placed a duplicate annotation on its antipode. ([#3563](https://github.com/mapbox/mapbox-gl-native/pull/3563))
+* Fixed an issue that caused an assertion failure if a `MGLShapeCollection` (a GeoJSON GeometryCollection) was created with an empty array of shapes. ([#7632](https://github.com/mapbox/mapbox-gl-native/pull/7632))
 * Improved the precision of annotations at zoom levels greater than 18. ([#5517](https://github.com/mapbox/mapbox-gl-native/pull/5517))
 
 ### Networking and offline maps