[ios, macos] Corrected polyline equality

Now that annotation classes override -isEqual:, it’s no longer appropriate to rely on -isEqual: or -containsObject: to check for the preexistence of an annotation. Those methods become deep equality tests, which have worse performance. Checking for identity allows the developer to add a polyline and polygon with identical coordinates, title, etc. to the map.

Implemented a missing -[MGLPolyline isEqual:].

Removed outdated comments about -annotationTagForAnnotation: being expensive.

2 files changed, 3 insertions, 2 deletions

diff --git a/platform/ios/CHANGELOG.md b/platform/ios/CHANGELOG.md
index 7ddb503543..6ffad0af16 100644
--- a/platform/ios/CHANGELOG.md
+++ b/platform/ios/CHANGELOG.md
@@ -45,6 +45,7 @@ Mapbox welcomes participation and contributions from everyone. Please read [CONT
 * Added a method to MGLMapViewDelegate, `-mapView:shouldChangeFromCamera:toCamera:`, that you can implement to restrict which parts the user can navigate to using gestures. ([#5584](https://github.com/mapbox/mapbox-gl-native/pull/5584))
 * Annotations are no longer deselected when the map is panned or zoomed, even if the annotation moves out of the visible bounds. ([#8022](https://github.com/mapbox/mapbox-gl-native/pull/8022))
 * Changing the coordinates of a point annotation no longer deselects the annotation. ([#8269](https://github.com/mapbox/mapbox-gl-native/pull/8269))
+* Fixed an issue preventing MGLMapView from adding a polyline annotation with the same coordinates as a polygon annotation. ([#8355](https://github.com/mapbox/mapbox-gl-native/pull/8355))
 * Fixed an issue where translucent, non-view-backed point annotations along tile boundaries would be drawn darker than expected. ([#6832](https://github.com/mapbox/mapbox-gl-native/pull/6832))
 * Double-tap and two-finger tap gestures now zoom to the nearest integer zoom level. ([#8027](https://github.com/mapbox/mapbox-gl-native/pull/8027))
 * The `MGLAnnotationView.annotation` property is now read-write. ([#8139](https://github.com/mapbox/mapbox-gl-native/pull/8139))
diff --git a/platform/ios/src/MGLMapView.mm b/platform/ios/src/MGLMapView.mm
index 8872261a88..2333df5c9a 100644
--- a/platform/ios/src/MGLMapView.mm
+++ b/platform/ios/src/MGLMapView.mm
@@ -3068,7 +3068,7 @@ public:
     return annotationContext.annotation;
 }
 
-/// Returns the annotation tag assigned to the given annotation. Relatively expensive.
+/// Returns the annotation tag assigned to the given annotation.
 - (MGLAnnotationTag)annotationTagForAnnotation:(id <MGLAnnotation>)annotation
 {
     if ( ! annotation || annotation == self.userLocation
@@ -3108,7 +3108,7 @@ public:
         NSAssert([annotation conformsToProtocol:@protocol(MGLAnnotation)], @"annotation should conform to MGLAnnotation");
 
         // adding the same annotation object twice is a no-op
-        if ([self.annotations containsObject:annotation])
+        if (_annotationTagsByAnnotation.count(annotation) != 0)
         {
             continue;
         }