Document -mapViewDidFailLoadingMap:withError: (#6145)

* [macos] Implement -mapViewDidFailLoadingMap:withError:

* [ios] Documented -mapViewDidFailLoadingMap:withError:

2 files changed, 12 insertions, 1 deletions

diff --git a/platform/ios/CHANGELOG.md b/platform/ios/CHANGELOG.md
index 24c1c8d70a..07518c1fad 100644
--- a/platform/ios/CHANGELOG.md
+++ b/platform/ios/CHANGELOG.md
@@ -22,6 +22,7 @@ Mapbox welcomes participation and contributions from everyone. Please read [CONT
 * The `icon-text-fit` and `icon-text-fit-padding` properties are now supported in stylesheets, allowing the background of a shield to automatically resize to fit the shield’s text. ([#5334](https://github.com/mapbox/mapbox-gl-native/pull/5334))
 * The `circle-pitch-scale` property is now supported in stylesheets, allowing circle features in a tilted base map to scale or remain the same size as the viewing distance changes. ([#5576](https://github.com/mapbox/mapbox-gl-native/pull/5576))
 * The `identifier` property of an MGLFeature may now be either a number or string. ([#5514](https://github.com/mapbox/mapbox-gl-native/pull/5514))
+* If MGLMapView is unable to obtain or parse a style, it now calls its delegate’s `-mapViewDidFailLoadingMap:withError:` method. ([#6145](https://github.com/mapbox/mapbox-gl-native/pull/6145))
 * Fixed crashes that could occur when loading a malformed stylesheet. ([#5736](https://github.com/mapbox/mapbox-gl-native/pull/5736))
 
 ### User location
diff --git a/platform/ios/src/MGLMapViewDelegate.h b/platform/ios/src/MGLMapViewDelegate.h
index db1327685a..3ec7d0d58b 100644
--- a/platform/ios/src/MGLMapViewDelegate.h
+++ b/platform/ios/src/MGLMapViewDelegate.h
@@ -81,7 +81,17 @@ NS_ASSUME_NONNULL_BEGIN
  */
 - (void)mapViewDidFinishLoadingMap:(MGLMapView *)mapView;
 
-// TODO
+/**
+ Tells the delegate that the map view was unable to load data needed for
+ displaying the map.
+ 
+ This method may be called for a variety of reasons, including a network
+ connection failure or a failure to fetch the style from the server. You can use
+ the given error message to notify the user that map data is unavailable.
+ 
+ @param mapView The map view that is unable to load the data.
+ @param error The reason the data could not be loaded.
+ */
 - (void)mapViewDidFailLoadingMap:(MGLMapView *)mapView withError:(NSError *)error;
 
 // TODO