Add limit check for gradient stops key value. (#4046)

Author: ShanMa1991

CHANGELOG.md

@@ -22,6 +22,7 @@
 * Fixed an issue where the incorrect destination building is highlighted after panning the correct building off screen. ([#4034](https://github.com/mapbox/mapbox-navigation-ios/pull/4034))
 * Fixed an issue where the maneuver arrow on the route line overlapped labels for points of interest. ([#4030](https://github.com/mapbox/mapbox-navigation-ios/pull/4030))
 * Fixed an issue where `NavigationMapView` injected with `NavigationOptions` isn't visible in active navigation. ([#4049](https://github.com/mapbox/mapbox-navigation-ios/pull/4049)) 
+* Fixed the crash caused by showing a route that doesn't contain coordinates. ([#4046](https://github.com/mapbox/mapbox-navigation-ios/pull/4046))
 
 ### CarPlay
 

Sources/MapboxNavigation/NavigationMapView+VanishingRouteLine.swift

@@ -323,6 +323,9 @@ extension NavigationMapView {
 
                 guard case let .lineString(lineString) = feature.geometry,
                       let distance = lineString.distance() else {
+                    if gradientStops.isEmpty {
+                        gradientStops[0.0] = lineSettings.baseColor
+                    }
                     return gradientStops
                 }
                 let minimumPercentGap = 2e-16
@@ -335,7 +338,7 @@ extension NavigationMapView {
                     if index + 1 < routeLineFeatures.count {
                         let segmentEndPercentTraveled = distanceTraveled / routeDistance
                         var currentGradientStop = lineSettings.isSoft ? segmentEndPercentTraveled - stopGap : Double(CGFloat(segmentEndPercentTraveled).nextDown)
-                        currentGradientStop = max(currentGradientStop, 0.0)
+                        currentGradientStop = min(max(currentGradientStop, 0.0), 1.0)
                         gradientStops[currentGradientStop] = associatedFeatureColor
                         lastRecordSegment = (currentGradientStop, associatedFeatureColor)
                     }
@@ -349,7 +352,7 @@ extension NavigationMapView {
                     } else {
                         let segmentStartPercentTraveled = distanceTraveled / routeDistance
                         var currentGradientStop = lineSettings.isSoft ? segmentStartPercentTraveled + stopGap : Double(CGFloat(segmentStartPercentTraveled).nextUp)
-                        currentGradientStop = min(currentGradientStop, 1.0)
+                        currentGradientStop = min(max(currentGradientStop, 0.0), 1.0)
                         gradientStops[currentGradientStop] = associatedFeatureColor
                     }
 
@@ -361,14 +364,14 @@ extension NavigationMapView {
                 } else {
                     let segmentStartPercentTraveled = distanceTraveled / routeDistance
                     var currentGradientStop = lineSettings.isSoft ? segmentStartPercentTraveled + stopGap : Double(CGFloat(segmentStartPercentTraveled).nextUp)
-                    currentGradientStop = min(currentGradientStop, 1.0)
+                    currentGradientStop = min(max(currentGradientStop, 0.0), 1.0)
                     gradientStops[currentGradientStop] = associatedFeatureColor
                 }
 
                 distanceTraveled = distanceTraveled + distance
                 let segmentEndPercentTraveled = distanceTraveled / routeDistance
                 var currentGradientStop = lineSettings.isSoft ? segmentEndPercentTraveled - stopGap : Double(CGFloat(segmentEndPercentTraveled).nextDown)
-                currentGradientStop = max(currentGradientStop, 0.0)
+                currentGradientStop = min(max(currentGradientStop, 0.0), 1.0)
                 gradientStops[currentGradientStop] = associatedFeatureColor
                 lastRecordSegment = (currentGradientStop, associatedFeatureColor)
             }
@@ -393,7 +396,7 @@ extension NavigationMapView {
         let baseColor: UIColor
         if let _ = congestionFeatures {
             overriddenLineLayerColor = lineLayerColorIfPresent(from: route)
-            baseColor = overriddenLineLayerColor ?? (isMain ? .trafficUnknown : .alternativeTrafficUnknown)
+            baseColor = overriddenLineLayerColor ?? (isMain ? trafficUnknownColor : alternativeTrafficUnknownColor)
         } else {
             overriddenLineLayerColor = lineLayerCasingColorIfPresent(from: route)
             baseColor = overriddenLineLayerColor ?? routeCasingColor

Tests/MapboxNavigationTests/VanishingRouteLineTests.swift

@@ -90,7 +90,7 @@ class VanishingRouteLineTests: TestCase {
                                 distance: routeLeg.distance,
                                 expectedTravelTime: routeLeg.expectedTravelTime,
                                 profileIdentifier: routeLeg.profileIdentifier)
-        let emptyRoute = Route(legs: [emptyLeg], shape: route.shape, distance: route.distance, expectedTravelTime: route.expectedTravelTime)
+        let emptyRoute = Route(legs: [emptyLeg], shape: LineString([]), distance: route.distance, expectedTravelTime: route.expectedTravelTime)
         return emptyRoute
     }
 
@@ -236,6 +236,26 @@ class VanishingRouteLineTests: TestCase {
         XCTAssertEqual(navigationMapView.fractionTraveled, 0.0, accuracy: 0)
     }
 
+    func testEmptyRouteGradientStops() {
+        let route = getEmptyRoute()
+        let congestionFeatures = route.congestionFeatures(legIndex: 0)
+        XCTAssertFalse(congestionFeatures.isEmpty, "Failed to generate features for empty route.")
+        
+        congestionFeatures.forEach { feature in
+            guard case let .lineString(lineString) = feature.geometry,
+                  lineString.distance() == nil else {
+                XCTFail("Failed to generate nil distance features with empty coordinates shape route.")
+                return
+            }
+        }
+        
+        navigationMapView.trafficUnknownColor = UIColor.blue
+        let gradientStops = navigationMapView.routeLineCongestionGradient(route,
+                                                                          congestionFeatures: congestionFeatures)
+        let expectedGradientStops: [Double: UIColor] = [0.0: navigationMapView.trafficUnknownColor]
+        XCTAssertEqual(gradientStops, expectedGradientStops,  "Failed to generate non-empty gradient stops for empty coordinates shape route.")
+    }
+    
     func testUnstartedRouteProgressWithValidRoute() {
         let route = getRoute()
         let routeProgress = getUnstartedRouteProgress(route: route)