[ios, macos] Make MGLMapView.style property nullable (#7664)

* [ios, macos] Made MGLMapView.style property nullable MGLMapView’s style property is now nullable (optional in Swift). The property is set to nil while the style loads and in the event that the style has failed to load. * [ios, macos] Switch to delegate method * [macos] Create MGLMapView programmatically for layer tests When MGLMapView is created via a nib, -initWithCoder: is called, causing styleURL to be set to nil, in turn causing the default Streets style to be loaded, fooling MGLStyleLayerTests into thinking one-line has been loaded. Instead, create MGLMapView programmatically, passing the intended style URL into the initializer, preventing Streets from being loaded.
2017-01-11 08:06:20 -08:00
parent 581fb3849d
commit 424c12499c
18 changed files with 99 additions and 90 deletions
--- a/platform/darwin/src/MGLCircleStyleLayer.h
+++ b/platform/darwin/src/MGLCircleStyleLayer.h
@@ -72,7 +72,7 @@ typedef NS_ENUM(NSUInteger, MGLCircleTranslationAnchor) {
 ])
 layer.circleOpacity = MGLStyleValue(rawValue: 0.7)
 layer.predicate = NSPredicate(format: "%K == %@", "marital-status", "married")
- mapView.style.addLayer(layer)
+ mapView.style?.addLayer(layer)
 ```
 */
@interface MGLCircleStyleLayer : MGLVectorStyleLayer
--- a/platform/darwin/src/MGLFillStyleLayer.h
+++ b/platform/darwin/src/MGLFillStyleLayer.h
@@ -45,7 +45,7 @@ typedef NS_ENUM(NSUInteger, MGLFillTranslationAnchor) {
 layer.sourceLayerIdentifier = "parks"
 layer.fillColor = MGLStyleValue(rawValue: .green)
 layer.predicate = NSPredicate(format: "type == %@", "national-park")
- mapView.style.addLayer(layer)
+ mapView.style?.addLayer(layer)
 ```
 */
@interface MGLFillStyleLayer : MGLVectorStyleLayer
--- a/platform/darwin/src/MGLLineStyleLayer.h
+++ b/platform/darwin/src/MGLLineStyleLayer.h
@@ -100,7 +100,7 @@ typedef NS_ENUM(NSUInteger, MGLLineTranslationAnchor) {
 layer.lineColor = MGLStyleValue(rawValue: .brown)
 layer.lineCap = MGLStyleValue(rawValue: NSValue(mglLineCap: .round))
 layer.predicate = NSPredicate(format: "%K == %@", "trail-type", "mountain-biking")
- mapView.style.addLayer(layer)
+ mapView.style?.addLayer(layer)
 ```
 */
@interface MGLLineStyleLayer : MGLVectorStyleLayer
--- a/platform/darwin/src/MGLRasterSource.h
+++ b/platform/darwin/src/MGLRasterSource.h
@@ -47,7 +47,7 @@ extern const MGLTileSourceOption MGLTileSourceOptionTileSize;
         MGLAttributionInfo(title: NSAttributedString(string: "© Mapbox"), url: URL(string: "http://mapbox.com"))
     ]
 ])
- mapView.style.addSource(source)
+ mapView.style?.addSource(source)
 ```
 */
@interface MGLRasterSource : MGLTileSource
--- a/platform/darwin/src/MGLRasterStyleLayer.h
+++ b/platform/darwin/src/MGLRasterStyleLayer.h
@@ -29,7 +29,7 @@ NS_ASSUME_NONNULL_BEGIN
 ```swift
 let layer = MGLRasterStyleLayer(identifier: "clouds", source: source)
 layer.rasterOpacity = MGLStyleValue(rawValue: 0.5)
- mapView.style.addLayer(layer)
+ mapView.style?.addLayer(layer)
 ```
 */
@interface MGLRasterStyleLayer : MGLForegroundStyleLayer
--- a/platform/darwin/src/MGLShapeSource.h
+++ b/platform/darwin/src/MGLShapeSource.h
@@ -105,7 +105,7 @@ extern const MGLShapeSourceOption MGLShapeSourceOptionSimplificationTolerance;
 let polyline = MGLPolylineFeature(coordinates: &coordinates, count: UInt(coordinates.count))
 let shape = MGLShapeCollectionFeature(shapes: [polyline])
 let source = MGLShapeSource(identifier: "lines", shape: shape, options: nil)
- mapView.style.addSource(source)
+ mapView.style?.addSource(source)
 ```
 */
@interface MGLShapeSource : MGLSource
--- a/platform/darwin/src/MGLSymbolStyleLayer.h
+++ b/platform/darwin/src/MGLSymbolStyleLayer.h
@@ -273,7 +273,7 @@ typedef NS_ENUM(NSUInteger, MGLTextTranslationAnchor) {
 layer.textJustification = MGLStyleValue(rawValue: NSValue(mglTextJustification: .left))
 layer.textAnchor = MGLStyleValue(rawValue: NSValue(mglTextAnchor: .left))
 layer.predicate = NSPredicate(format: "%K == %@", "venue-type", "coffee")
- mapView.style.addLayer(layer)
+ mapView.style?.addLayer(layer)
 ```
 */
@interface MGLSymbolStyleLayer : MGLVectorStyleLayer
--- a/platform/darwin/src/MGLVectorSource.h
+++ b/platform/darwin/src/MGLVectorSource.h
@@ -35,7 +35,7 @@ NS_ASSUME_NONNULL_BEGIN
         MGLAttributionInfo(title: NSAttributedString(string: "© Mapbox"), url: URL(string: "http://mapbox.com"))
     ]
 ])
- mapView.style.addSource(source)
+ mapView.style?.addSource(source)
 ```
 */
@interface MGLVectorSource : MGLTileSource
--- a/platform/darwin/src/MGLVectorStyleLayer.h
+++ b/platform/darwin/src/MGLVectorStyleLayer.h
@@ -144,7 +144,7 @@ NS_ASSUME_NONNULL_BEGIN
 let layer = MGLLineStyleLayer(identifier: "contour", source: terrain)
 layer.sourceLayerIdentifier = "contours"
 layer.predicate = NSPredicate(format: "(index == 5 || index == 10) && ele >= 1500.0")
- mapView.style.addLayer(layer)
+ mapView.style?.addLayer(layer)
 ```
 */
@property (nonatomic, nullable) NSPredicate *predicate;
--- a/platform/darwin/test/MGLDocumentationExampleTests.swift
+++ b/platform/darwin/test/MGLDocumentationExampleTests.swift
@@ -68,10 +68,10 @@ class MGLDocumentationExampleTests: XCTestCase, MGLMapViewDelegate {
        let polyline = MGLPolylineFeature(coordinates: &coordinates, count: UInt(coordinates.count))
        let shape = MGLShapeCollectionFeature(shapes: [polyline])
        let source = MGLShapeSource(identifier: "lines", shape: shape, options: nil)
-        mapView.style.addSource(source)
+        mapView.style?.addSource(source)
        //#-end-example-code

-        XCTAssertNotNil(mapView.style.source(withIdentifier: "lines"))
+        XCTAssertNotNil(mapView.style?.source(withIdentifier: "lines"))
    }

    func testMGLRasterSource() {
@@ -84,10 +84,10 @@ class MGLDocumentationExampleTests: XCTestCase, MGLMapViewDelegate {
                MGLAttributionInfo(title: NSAttributedString(string: "© Mapbox"), url: URL(string: "http://mapbox.com"))
            ]
        ])
-        mapView.style.addSource(source)
+        mapView.style?.addSource(source)
        //#-end-example-code

-        XCTAssertNotNil(mapView.style.source(withIdentifier: "clouds"))
+        XCTAssertNotNil(mapView.style?.source(withIdentifier: "clouds"))
    }

    func testMGLVectorSource() {
@@ -99,15 +99,15 @@ class MGLDocumentationExampleTests: XCTestCase, MGLMapViewDelegate {
                MGLAttributionInfo(title: NSAttributedString(string: "© Mapbox"), url: URL(string: "http://mapbox.com"))
            ]
        ])
-        mapView.style.addSource(source)
+        mapView.style?.addSource(source)
        //#-end-example-code

-        XCTAssertNotNil(mapView.style.source(withIdentifier: "pois"))
+        XCTAssertNotNil(mapView.style?.source(withIdentifier: "pois"))
    }

    func testMGLCircleStyleLayer() {
        let population = MGLVectorSource(identifier: "population", configurationURL: URL(string: "https://example.com/style.json")!)
-        mapView.style.addSource(population)
+        mapView.style?.addSource(population)
        
        //#-example-code
        let layer = MGLCircleStyleLayer(identifier: "circles", source: population)
@@ -119,15 +119,15 @@ class MGLDocumentationExampleTests: XCTestCase, MGLMapViewDelegate {
        ])
        layer.circleOpacity = MGLStyleValue(rawValue: 0.7)
        layer.predicate = NSPredicate(format: "%K == %@", "marital-status", "married")
-        mapView.style.addLayer(layer)
+        mapView.style?.addLayer(layer)
        //#-end-example-code

-        XCTAssertNotNil(mapView.style.layer(withIdentifier: "circles"))
+        XCTAssertNotNil(mapView.style?.layer(withIdentifier: "circles"))
    }

    func testMGLLineStyleLayer() {
        let trails = MGLVectorSource(identifier: "trails", configurationURL: URL(string: "https://example.com/style.json")!)
-        mapView.style.addSource(trails)
+        mapView.style?.addSource(trails)

        //#-example-code
        let layer = MGLLineStyleLayer(identifier: "trails-path", source: trails)
@@ -139,30 +139,30 @@ class MGLDocumentationExampleTests: XCTestCase, MGLMapViewDelegate {
        layer.lineColor = MGLStyleValue(rawValue: .brown)
        layer.lineCap = MGLStyleValue(rawValue: NSValue(mglLineCap: .round))
        layer.predicate = NSPredicate(format: "%K == %@", "trail-type", "mountain-biking")
-        mapView.style.addLayer(layer)
+        mapView.style?.addLayer(layer)
        //#-end-example-code

-        XCTAssertNotNil(mapView.style.layer(withIdentifier: "trails-path"))
+        XCTAssertNotNil(mapView.style?.layer(withIdentifier: "trails-path"))
    }

    func testMGLFillStyleLayer() {
        let parks = MGLVectorSource(identifier: "parks", configurationURL: URL(string: "https://example.com/style.json")!)
-        mapView.style.addSource(parks)
+        mapView.style?.addSource(parks)

        //#-example-code
        let layer = MGLFillStyleLayer(identifier: "parks", source: parks)
        layer.sourceLayerIdentifier = "parks"
        layer.fillColor = MGLStyleValue(rawValue: .green)
        layer.predicate = NSPredicate(format: "type == %@", "national-park")
-        mapView.style.addLayer(layer)
+        mapView.style?.addLayer(layer)
        //#-end-example-code

-        XCTAssertNotNil(mapView.style.layer(withIdentifier: "parks"))
+        XCTAssertNotNil(mapView.style?.layer(withIdentifier: "parks"))
    }

    func testMGLSymbolStyleLayer() {
        let pois = MGLVectorSource(identifier: "pois", configurationURL: URL(string: "https://example.com/style.json")!)
-        mapView.style.addSource(pois)
+        mapView.style?.addSource(pois)

        //#-example-code
        let layer = MGLSymbolStyleLayer(identifier: "coffeeshops", source: pois)
@@ -179,10 +179,10 @@ class MGLDocumentationExampleTests: XCTestCase, MGLMapViewDelegate {
        layer.textJustification = MGLStyleValue(rawValue: NSValue(mglTextJustification: .left))
        layer.textAnchor = MGLStyleValue(rawValue: NSValue(mglTextAnchor: .left))
        layer.predicate = NSPredicate(format: "%K == %@", "venue-type", "coffee")
-        mapView.style.addLayer(layer)
+        mapView.style?.addLayer(layer)
        //#-end-example-code

-        XCTAssertNotNil(mapView.style.layer(withIdentifier: "coffeeshops"))
+        XCTAssertNotNil(mapView.style?.layer(withIdentifier: "coffeeshops"))
    }

    func testMGLRasterStyleLayer() {
@@ -194,28 +194,28 @@ class MGLDocumentationExampleTests: XCTestCase, MGLMapViewDelegate {
                MGLAttributionInfo(title: NSAttributedString(string: "© Mapbox"), url: URL(string: "http://mapbox.com"))
            ]
        ])
-        mapView.style.addSource(source)
+        mapView.style?.addSource(source)

        //#-example-code
        let layer = MGLRasterStyleLayer(identifier: "clouds", source: source)
        layer.rasterOpacity = MGLStyleValue(rawValue: 0.5)
-        mapView.style.addLayer(layer)
+        mapView.style?.addLayer(layer)
        //#-end-example-code

-        XCTAssertNotNil(mapView.style.layer(withIdentifier: "clouds"))
+        XCTAssertNotNil(mapView.style?.layer(withIdentifier: "clouds"))
    }

    func testMGLVectorStyleLayer$predicate() {
        let terrain = MGLVectorSource(identifier: "terrain", configurationURL: URL(string: "https://example.com/style.json")!)
-        mapView.style.addSource(terrain)
+        mapView.style?.addSource(terrain)

        //#-example-code
        let layer = MGLLineStyleLayer(identifier: "contour", source: terrain)
        layer.sourceLayerIdentifier = "contours"
        layer.predicate = NSPredicate(format: "(index == 5 || index == 10) && ele >= 1500.0")
-        mapView.style.addLayer(layer)
+        mapView.style?.addLayer(layer)
        //#-end-example-code

-        XCTAssertNotNil(mapView.style.layer(withIdentifier: "contour"))
+        XCTAssertNotNil(mapView.style?.layer(withIdentifier: "contour"))
    }
 }
--- a/platform/darwin/test/MGLStyleLayerTests.h
+++ b/platform/darwin/test/MGLStyleLayerTests.h
@@ -5,7 +5,6 @@
@interface MGLStyleLayerTests : XCTestCase <MGLMapViewDelegate>

@property (nonatomic) IBOutlet MGLMapView *mapView;
-@property (nonatomic) XCTestExpectation *expectation;
@property (nonatomic, copy, readonly, class) NSString *layerType;

 - (void)testPropertyName:(NSString *)name isBoolean:(BOOL)isBoolean;
--- a/platform/darwin/test/MGLStyleLayerTests.m
+++ b/platform/darwin/test/MGLStyleLayerTests.m
@@ -11,18 +11,27 @@
 - (void)setUp {
    [super setUp];
    [MGLAccountManager setAccessToken:@"pk.feedcafedeadbeefbadebede"];
+    NSURL *styleURL = [[NSBundle bundleForClass:[self class]] URLForResource:@"one-liner" withExtension:@"json"];
 #if TARGET_OS_IPHONE
    UIApplication *app = [UIApplication sharedApplication];
    UIViewController *vc = [[UIViewController alloc] init];
    app.keyWindow.rootViewController = vc;
    [vc view]; // Force load xib
-    _mapView = [[MGLMapView alloc] initWithFrame:CGRectMake(0, 0, 256, 256)];
+    _mapView = [[MGLMapView alloc] initWithFrame:CGRectMake(0, 0, 256, 256) styleURL:styleURL];
    [vc.view addSubview:_mapView];
-    _mapView.delegate = self;
 #else
    NSWindowController *windowController = [[NSWindowController alloc] initWithWindowNibName:@"MGLStyleLayerTests" owner:self];
+    NSView *contentView = windowController.window.contentView;
+    _mapView = [[MGLMapView alloc] initWithFrame:contentView.bounds styleURL:styleURL];
+    [contentView addSubview:_mapView];
    [windowController showWindow:nil];
 #endif
+    _mapView.delegate = self;
+    XCTAssertNil(_mapView.style);
+    [self keyValueObservingExpectationForObject:self.mapView keyPath:@"style" handler:^BOOL(MGLMapView * _Nonnull observedMapView, NSDictionary * _Nonnull change) {
+        return observedMapView.style != nil;
+    }];
+    [self waitForExpectationsWithTimeout:1 handler:nil];
 }

 - (void)tearDown {
--- a/platform/darwin/test/MGLStyleLayerTests.xib
+++ b/platform/darwin/test/MGLStyleLayerTests.xib
@@ -1,38 +1,21 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<document type="com.apple.InterfaceBuilder3.Cocoa.XIB" version="3.0" toolsVersion="10117" systemVersion="16A304a" targetRuntime="MacOSX.Cocoa" propertyAccessControl="none" useAutolayout="YES" customObjectInstantitationMethod="direct">
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<document type="com.apple.InterfaceBuilder3.Cocoa.XIB" version="3.0" toolsVersion="11762" systemVersion="15G1212" targetRuntime="MacOSX.Cocoa" propertyAccessControl="none" useAutolayout="YES" customObjectInstantitationMethod="direct">
    <dependencies>
-        <plugIn identifier="com.apple.InterfaceBuilder.CocoaPlugin" version="10117"/>
+        <plugIn identifier="com.apple.InterfaceBuilder.CocoaPlugin" version="11762"/>
+        <capability name="documents saved in the Xcode 8 format" minToolsVersion="8.0"/>
    </dependencies>
    <objects>
-        <customObject id="-2" userLabel="File's Owner" customClass="MGLMapViewTests">
-            <connections>
-                <outlet property="mapView" destination="6RL-d9-juy" id="0ch-aR-Um6"/>
-            </connections>
-        </customObject>
+        <customObject id="-2" userLabel="File's Owner" customClass="MGLMapViewTests"/>
        <customObject id="-1" userLabel="First Responder" customClass="FirstResponder"/>
        <customObject id="-3" userLabel="Application" customClass="NSObject"/>
        <window title="MGLMapViewTests" allowsToolTipsWhenApplicationIsInactive="NO" autorecalculatesKeyViewLoop="NO" oneShot="NO" releasedWhenClosed="NO" animationBehavior="default" id="QvC-M9-y7g">
            <windowStyleMask key="styleMask" titled="YES" closable="YES" miniaturizable="YES" resizable="YES"/>
            <windowPositionMask key="initialPositionMask" leftStrut="YES" rightStrut="YES" topStrut="YES" bottomStrut="YES"/>
            <rect key="contentRect" x="196" y="240" width="256" height="256"/>
-            <rect key="screenRect" x="0.0" y="0.0" width="1920" height="1058"/>
+            <rect key="screenRect" x="0.0" y="0.0" width="1280" height="777"/>
            <view key="contentView" wantsLayer="YES" id="EiT-Mj-1SZ">
                <rect key="frame" x="0.0" y="0.0" width="256" height="256"/>
                <autoresizingMask key="autoresizingMask"/>
-                <subviews>
-                    <customView translatesAutoresizingMaskIntoConstraints="NO" id="6RL-d9-juy" customClass="MGLMapView">
-                        <rect key="frame" x="0.0" y="0.0" width="256" height="256"/>
-                        <connections>
-                            <outlet property="delegate" destination="-2" id="6kS-ct-JEg"/>
-                        </connections>
-                    </customView>
-                </subviews>
-                <constraints>
-                    <constraint firstItem="6RL-d9-juy" firstAttribute="leading" secondItem="EiT-Mj-1SZ" secondAttribute="leading" id="KEN-aL-UF0"/>
-                    <constraint firstAttribute="bottom" secondItem="6RL-d9-juy" secondAttribute="bottom" id="V27-f3-xHZ"/>
-                    <constraint firstAttribute="trailing" secondItem="6RL-d9-juy" secondAttribute="trailing" id="vjq-iM-OyA"/>
-                    <constraint firstItem="6RL-d9-juy" firstAttribute="top" secondItem="EiT-Mj-1SZ" secondAttribute="top" id="yWg-v4-wJB"/>
-                </constraints>
            </view>
        </window>
    </objects>
--- a/platform/darwin/test/MGLStyleTests.mm
+++ b/platform/darwin/test/MGLStyleTests.mm
@@ -39,7 +39,13 @@
    [super setUp];
    
    [MGLAccountManager setAccessToken:@"pk.feedcafedeadbeefbadebede"];
-    self.mapView = [[MGLMapView alloc] initWithFrame:CGRectMake(0, 0, 100, 100)];
+    NSURL *styleURL = [[NSBundle bundleForClass:[self class]] URLForResource:@"one-liner" withExtension:@"json"];
+    self.mapView = [[MGLMapView alloc] initWithFrame:CGRectMake(0, 0, 100, 100) styleURL:styleURL];
+    XCTAssertNil(self.mapView.style);
+    [self keyValueObservingExpectationForObject:self.mapView keyPath:@"style" handler:^BOOL(MGLMapView * _Nonnull observedMapView, NSDictionary * _Nonnull change) {
+        return observedMapView.style != nil;
+    }];
+    [self waitForExpectationsWithTimeout:1 handler:nil];
 }

 - (void)tearDown {
@@ -250,12 +256,16 @@
    [self.style insertLayer:layer0 belowLayer:layer1];
    
    NSArray<MGLStyleLayer *> *layers = [self.style layers];
+    NSUInteger startIndex = 0;
+    if ([layers.firstObject.identifier isEqualToString:@"com.mapbox.annotations.points"]) {
+        startIndex++;
+    }
    
-    XCTAssert([[layers[0] identifier] isEqualToString:layer0.identifier]);
-    XCTAssert([[layers[1] identifier] isEqualToString:layer1.identifier]);
-    XCTAssert([[layers[2] identifier] isEqualToString:layer2.identifier]);
-    XCTAssert([[layers[3] identifier] isEqualToString:layer3.identifier]);
-    XCTAssert([[layers[4] identifier] isEqualToString:layer4.identifier]);
+    XCTAssertEqualObjects(layers[startIndex++].identifier, layer0.identifier);
+    XCTAssertEqualObjects(layers[startIndex++].identifier, layer1.identifier);
+    XCTAssertEqualObjects(layers[startIndex++].identifier, layer2.identifier);
+    XCTAssertEqualObjects(layers[startIndex++].identifier, layer3.identifier);
+    XCTAssertEqualObjects(layers[startIndex++].identifier, layer4.identifier);
 }

@end
--- a/platform/ios/src/MGLMapView.h
+++ b/platform/ios/src/MGLMapView.h
@@ -123,6 +123,13 @@ IB_DESIGNABLE
 Unlike the `styleURL` property, this property is set to an object that allows
 you to manipulate every aspect of the style locally.
 
+ If the style is loading, this property is set to `nil` until the style finishes
+ loading. If the style has failed to load, this property is set to `nil`.
+ Because the style loads asynchronously, you should manipulate it in the
+ `-[MGLMapViewDelegate mapView:didFinishLoadingStyle:]` or
+ `-[MGLMapViewDelegate mapViewDidFinishLoadingMap:]` method. It is not possible
+ to manipulate the style before it has finished loading.
+ 
 @note The default styles provided by Mapbox contain sources and layers with
    identifiers that will change over time. Applications that use APIs that
    manipulate a style's sources and layers must first set the style URL to an
@@ -130,7 +137,7 @@ IB_DESIGNABLE
    `+[MGLStyle outdoorsStyleURLWithVersion:]`, `MGLMapView`'s “Style URL”
    inspectable in Interface Builder, or a manually constructed `NSURL`.
 */
-@property (nonatomic, readonly) MGLStyle *style;
+@property (nonatomic, readonly, nullable) MGLStyle *style;

 /**
 URLs of the styles bundled with the library.
--- a/platform/ios/src/MGLMapView.mm
+++ b/platform/ios/src/MGLMapView.mm
@@ -347,6 +347,11 @@ public:
    return self;
 }

+ (NS_SET_OF(NSString *) *)keyPathsForValuesAffectingStyle
+{
+    return [NSSet setWithObject:@"styleURL"];
+}
+
 + (NS_SET_OF(NSString *) *)keyPathsForValuesAffectingStyleURL
 {
    return [NSSet setWithObjects:@"styleURL__", nil];
@@ -369,10 +374,8 @@ public:
    }

    styleURL = styleURL.mgl_URLByStandardizingScheme;
-    [self willChangeValueForKey:@"style"];
-    _style = [[MGLStyle alloc] initWithMapView:self];
+    self.style = nil;
    _mbglMap->setStyleURL([[styleURL absoluteString] UTF8String]);
-    [self didChangeValueForKey:@"style"];
 }

 - (IBAction)reloadStyle:(__unused id)sender {
@@ -4682,11 +4685,7 @@ public:
        }
        case mbgl::MapChangeDidFinishLoadingStyle:
        {
-            [self.style willChangeValueForKey:@"name"];
-            [self.style willChangeValueForKey:@"sources"];
-            [self.style didChangeValueForKey:@"sources"];
-            [self.style willChangeValueForKey:@"layers"];
-            [self.style didChangeValueForKey:@"layers"];
+            self.style = [[MGLStyle alloc] initWithMapView:self];
            if ([self.delegate respondsToSelector:@selector(mapView:didFinishLoadingStyle:)])
            {
                [self.delegate mapView:self didFinishLoadingStyle:self.style];
--- a/platform/macos/src/MGLMapView.h
+++ b/platform/macos/src/MGLMapView.h
@@ -94,6 +94,13 @@ IB_DESIGNABLE
 Unlike the `styleURL` property, this property is set to an object that allows
 you to manipulate every aspect of the style locally.
 
+ If the style is loading, this property is set to `nil` until the style finishes
+ loading. If the style has failed to load, this property is set to `nil`.
+ Because the style loads asynchronously, you should manipulate it in the
+ `-[MGLMapViewDelegate mapView:didFinishLoadingStyle:]` or
+ `-[MGLMapViewDelegate mapViewDidFinishLoadingMap:]` method. It is not possible
+ to manipulate the style before it has finished loading.
+ 
 @note The default styles provided by Mapbox contain sources and layers with
    identifiers that will change over time. Applications that use APIs that
    manipulate a style's sources and layers must first set the style URL to an
@@ -101,7 +108,7 @@ IB_DESIGNABLE
    `+[MGLStyle outdoorsStyleURLWithVersion:]`, `MGLMapView`'s “Style URL”
    inspectable in Interface Builder, or a manually constructed `NSURL`.
 */
-@property (nonatomic, readonly) MGLStyle *style;
+@property (nonatomic, readonly, nullable) MGLStyle *style;

 /**
 URL of the style currently displayed in the receiver.
--- a/platform/macos/src/MGLMapView.mm
+++ b/platform/macos/src/MGLMapView.mm
@@ -590,6 +590,10 @@ public:

 #pragma mark Style

+ (NS_SET_OF(NSString *) *)keyPathsForValuesAffectingStyle {
+    return [NSSet setWithObject:@"styleURL"];
+}
+
 - (nonnull NSURL *)styleURL {
    NSString *styleURLString = @(_mbglMap->getStyleURL().c_str()).mgl_stringOrNilIfEmpty;
    return styleURLString ? [NSURL URLWithString:styleURLString] : [MGLStyle streetsStyleURLWithVersion:MGLStyleDefaultVersion];
@@ -611,10 +615,8 @@ public:
    }

    styleURL = styleURL.mgl_URLByStandardizingScheme;
-    [self willChangeValueForKey:@"style"];
-    _style = [[MGLStyle alloc] initWithMapView:self];
+    self.style = nil;
    _mbglMap->setStyleURL(styleURL.absoluteString.UTF8String);
-    [self didChangeValueForKey:@"style"];
 }

 - (IBAction)reloadStyle:(__unused id)sender {
@@ -623,6 +625,10 @@ public:
    self.styleURL = styleURL;
 }

+- (mbgl::Map *)mbglMap {
+    return _mbglMap;
+}
+
 #pragma mark View hierarchy and drawing

 - (void)viewWillMoveToWindow:(NSWindow *)newWindow {
@@ -916,11 +922,7 @@ public:
        }
        case mbgl::MapChangeDidFinishLoadingStyle:
        {
-            [self.style willChangeValueForKey:@"name"];
-            [self.style willChangeValueForKey:@"sources"];
-            [self.style didChangeValueForKey:@"sources"];
-            [self.style willChangeValueForKey:@"layers"];
-            [self.style didChangeValueForKey:@"layers"];
+            self.style = [[MGLStyle alloc] initWithMapView:self];
            if ([self.delegate respondsToSelector:@selector(mapView:didFinishLoadingStyle:)])
            {
                [self.delegate mapView:self didFinishLoadingStyle:self.style];
@@ -2268,13 +2270,6 @@ public:
    }
 }

-#pragma mark - Runtime styling
-
- (mbgl::Map *)mbglMap
-{
-    return _mbglMap;
-}
-
 #pragma mark MGLMultiPointDelegate methods

 - (double)alphaForShapeAnnotation:(MGLShape *)annotation {