iOS: Handle GeoJSON with empty coordinates

platform/darwin/src/MLNShape.mm

@@ -11,6 +11,86 @@
   return lhs.latitude == rhs.latitude && lhs.longitude == rhs.longitude;
 }
 
+static BOOL MLNIsGeoJSONGeometryType(NSString *type) {
+  return [type isEqualToString:@"Point"] || [type isEqualToString:@"MultiPoint"] ||
+         [type isEqualToString:@"LineString"] || [type isEqualToString:@"MultiLineString"] ||
+         [type isEqualToString:@"Polygon"] || [type isEqualToString:@"MultiPolygon"];
+}
+
+static NSRegularExpression *MLNEmptyArrayRegularExpression(void) {
+  static NSRegularExpression *regularExpression;
+  static dispatch_once_t onceToken;
+  dispatch_once(&onceToken, ^{
+    regularExpression = [NSRegularExpression regularExpressionWithPattern:@"\\[\\s*\\]"
+                                                                  options:0
+                                                                    error:nil];
+  });
+  return regularExpression;
+}
+
+static BOOL MLNReplaceEmptyFeatureCoordinates(id object) {
+  if (![object isKindOfClass:[NSMutableDictionary class]]) {
+    return NO;
+  }
+
+  NSMutableDictionary *dictionary = object;
+  NSString *type = dictionary[@"type"];
+  if (![type isKindOfClass:[NSString class]]) {
+    return NO;
+  }
+  if ([type isEqualToString:@"Feature"]) {
+    id geometry = dictionary[@"geometry"];
+    if (![geometry isKindOfClass:[NSDictionary class]]) {
+      return NO;
+    }
+
+    NSString *geometryType = geometry[@"type"];
+    id coordinates = geometry[@"coordinates"];
+    if (![geometryType isKindOfClass:[NSString class]] || !MLNIsGeoJSONGeometryType(geometryType) ||
+        ![coordinates isKindOfClass:[NSArray class]] || [coordinates count] != 0) {
+      return NO;
+    }
+
+    dictionary[@"geometry"] = [NSNull null];
+    return YES;
+  }
+
+  if (![type isEqualToString:@"FeatureCollection"]) {
+    return NO;
+  }
+
+  NSArray *features = dictionary[@"features"];
+  if (![features isKindOfClass:[NSArray class]]) {
+    return NO;
+  }
+
+  BOOL changed = NO;
+  for (id feature in features) {
+    changed |= MLNReplaceEmptyFeatureCoordinates(feature);
+  }
+  return changed;
+}
+
+static NSString *MLNGeoJSONStringByReplacingEmptyFeatureCoordinates(NSString *string) {
+  NSRange range = NSMakeRange(0, string.length);
+  if (![MLNEmptyArrayRegularExpression() firstMatchInString:string options:0 range:range]) {
+    return string;
+  }
+
+  NSData *data = [string dataUsingEncoding:NSUTF8StringEncoding];
+  id jsonObject = [NSJSONSerialization JSONObjectWithData:data
+                                                  options:NSJSONReadingMutableContainers
+                                                    error:nil];
+  if (!MLNReplaceEmptyFeatureCoordinates(jsonObject)) {
+    return string;
+  }
+
+  NSData *updatedData = [NSJSONSerialization dataWithJSONObject:jsonObject options:0 error:nil];
+  NSString *updatedString = [[NSString alloc] initWithData:updatedData
+                                                  encoding:NSUTF8StringEncoding];
+  return updatedString ?: string;
+}
+
 @implementation MLNShape
 
 + (nullable MLNShape *)shapeWithData:(NSData *)data
@@ -24,8 +104,9 @@ + (nullable MLNShape *)shapeWithData:(NSData *)data
     return nil;
   }
 
+  NSString *normalizedString = MLNGeoJSONStringByReplacingEmptyFeatureCoordinates(string);
   try {
-    const auto geojson = mapbox::geojson::parse(string.UTF8String);
+    const auto geojson = mapbox::geojson::parse(normalizedString.UTF8String);
     return MLNShapeFromGeoJSON(geojson);
   } catch (std::runtime_error &err) {
     if (outError) {

platform/darwin/test/MLNShapeSourceTests.mm

@@ -91,6 +91,72 @@ - (void)testMLNShapeSourceWithDataMultipleFeatures {
   XCTAssertTrue([collection.shapes.firstObject isMemberOfClass:[MLNPolylineFeature class]]);
 }
 
+- (void)testMLNShapeSourceWithNullGeometry {
+  NSData *data = [@"{\"type\":\"Feature\",\"properties\":{},\"geometry\":null}"
+      dataUsingEncoding:NSUTF8StringEncoding];
+  NSError *error = nil;
+  MLNShape *shape = [MLNShape shapeWithData:data encoding:NSUTF8StringEncoding error:&error];
+
+  XCTAssertNil(error);
+  XCTAssertTrue([shape isKindOfClass:[MLNEmptyFeature class]]);
+
+  MLNShapeSource *source;
+  XCTAssertNoThrow(source = [[MLNShapeSource alloc] initWithIdentifier:@"source-id"
+                                                                 shape:shape
+                                                               options:nil]);
+  XCTAssertNotNil(source.shape);
+}
+
+- (void)testMLNShapeSourceWithEmptyFeatureCoordinates {
+  NSArray<NSString *> *geometryTypes =
+      @[ @"Point", @"MultiPoint", @"LineString", @"MultiLineString", @"Polygon", @"MultiPolygon" ];
+  for (NSString *geometryType in geometryTypes) {
+    NSString *geoJSON =
+        [NSString stringWithFormat:@"{\"type\":\"Feature\",\"properties\":{},\"geometry\":{"
+                                   @"\"type\":\"%@\",\"coordinates\":[ ]}}",
+                                   geometryType];
+    NSData *data = [geoJSON dataUsingEncoding:NSUTF8StringEncoding];
+    NSError *error = nil;
+    MLNShape *shape = [MLNShape shapeWithData:data encoding:NSUTF8StringEncoding error:&error];
+
+    XCTAssertNil(error);
+    XCTAssertTrue([shape isKindOfClass:[MLNEmptyFeature class]]);
+
+    MLNShapeSource *source;
+    XCTAssertNoThrow(source = [[MLNShapeSource alloc] initWithIdentifier:@"source-id"
+                                                                   shape:shape
+                                                                 options:nil]);
+    XCTAssertNotNil(source.shape);
+  }
+}
+
+- (void)testMLNShapeSourceWithEmptyFeatureAndValidSibling {
+  NSString *geoJSON = @"{\"type\":\"FeatureCollection\",\"features\":["
+                       "{\"type\":\"Feature\",\"properties\":{},\"geometry\":{\"type\":\"Point\","
+                       "\"coordinates\":[]}},"
+                       "{\"type\":\"Feature\",\"properties\":{\"name\":\"Café\"},"
+                       "\"geometry\":{\"type\":\"Point\","
+                       "\"coordinates\":[0,0]}}]}";
+  NSData *data = [geoJSON dataUsingEncoding:NSISOLatin1StringEncoding];
+  NSError *error = nil;
+  MLNShapeCollectionFeature *collection =
+      (MLNShapeCollectionFeature *)[MLNShape shapeWithData:data
+                                                  encoding:NSISOLatin1StringEncoding
+                                                     error:&error];
+
+  XCTAssertNil(error);
+  XCTAssertEqual(collection.shapes.count, 2UL);
+  XCTAssertTrue([collection.shapes[0] isKindOfClass:[MLNEmptyFeature class]]);
+  XCTAssertTrue([collection.shapes[1] isKindOfClass:[MLNPointFeature class]]);
+  XCTAssertEqualObjects([collection.shapes[1] attributeForKey:@"name"], @"Café");
+
+  MLNShapeSource *source;
+  XCTAssertNoThrow(source = [[MLNShapeSource alloc] initWithIdentifier:@"source-id"
+                                                                 shape:collection
+                                                               options:nil]);
+  XCTAssertNotNil(source.shape);
+}
+
 - (void)testMLNShapeSourceWithSingleGeometry {
   NSData *data =
       [@"{\"type\": \"Point\", \"coordinates\": [0, 0]}" dataUsingEncoding:NSUTF8StringEncoding];

platform/ios/CHANGELOG.md

@@ -4,6 +4,7 @@ MapLibre welcomes participation and contributions from everyone. Please read [`M
 
 ## 6.29.0
 
+- iOS: Accept GeoJSON features with empty coordinate arrays.
 - fix(core): accept alpha in hsl colors ([#4435](https://github.com/maplibre/maplibre-native/pull/4435)).
 - fix(core): repaint feature-state-driven symbol paint properties ([#4445](https://github.com/maplibre/maplibre-native/pull/4445)).
 - Make string expressions operate on unicode ([#4344](https://github.com/maplibre/maplibre-native/pull/4344)).

platform/macos/CHANGELOG.md

@@ -4,6 +4,7 @@ MapLibre welcomes participation and contributions from everyone. Please read [`C
 
 ## 6.27.0
 
+- Accept GeoJSON features with empty coordinate arrays.
 - First automated native macOS XCFramework release ([#4088](https://github.com/maplibre/maplibre-native/issues/4088)).
 - Add Bazel `MapLibre.dynamic` and `MapLibre.static` xcframework targets for macOS ([#4113](https://github.com/maplibre/maplibre-native/pull/4113)).
 - Fix Xcode 26 build compatibility ([#4226](https://github.com/maplibre/maplibre-native/pull/4226)).