[ios] Tweaks for analyzer warnings

8 files changed, 47 insertions, 30 deletions

diff --git a/platform/darwin/src/MGLStyleValue_Private.h b/platform/darwin/src/MGLStyleValue_Private.h
index fee34b4b71..376bf5e73b 100644
--- a/platform/darwin/src/MGLStyleValue_Private.h
+++ b/platform/darwin/src/MGLStyleValue_Private.h
@@ -291,7 +291,7 @@ private: // Private utilities for converting from mbgl to mgl values
     }
 
     // Array
-    static ObjCType toMGLRawStyleValue(const std::vector<MBGLElement> &mbglStopValue) {
+    static NSArray<NSExpression*> *toMGLRawStyleValue(const std::vector<MBGLElement> &mbglStopValue) {
         NSMutableArray *array = [NSMutableArray arrayWithCapacity:mbglStopValue.size()];
         for (const auto &mbglElement: mbglStopValue) {
             [array addObject:[NSExpression expressionForConstantValue:toMGLRawStyleValue(mbglElement)]];
diff --git a/platform/darwin/src/NSExpression+MGLAdditions.mm b/platform/darwin/src/NSExpression+MGLAdditions.mm
index 9dad00e56e..fe2e5a0a31 100644
--- a/platform/darwin/src/NSExpression+MGLAdditions.mm
+++ b/platform/darwin/src/NSExpression+MGLAdditions.mm
@@ -792,19 +792,24 @@ NSArray *MGLSubexpressionsWithJSONObjects(NSArray *objects) {
             } else if ([curveType isEqualToString:@"cubic-bezier"]) {
                 curveParameters = @[@"literal", [interpolationOptions subarrayWithRange:NSMakeRange(1, 4)]];
             }
-            NSExpression *curveParameterExpression = [NSExpression expressionWithMGLJSONObject:curveParameters];
-            argumentObjects = [argumentObjects subarrayWithRange:NSMakeRange(1, argumentObjects.count - 1)];
-            NSExpression *inputExpression = [NSExpression expressionWithMGLJSONObject:argumentObjects.firstObject];
-            NSArray *stopExpressions = [argumentObjects subarrayWithRange:NSMakeRange(1, argumentObjects.count - 1)];
-            NSMutableDictionary *stops = [NSMutableDictionary dictionaryWithCapacity:stopExpressions.count / 2];
-            NSEnumerator *stopEnumerator = stopExpressions.objectEnumerator;
-            while (NSNumber *key = stopEnumerator.nextObject) {
-                NSExpression *valueExpression = stopEnumerator.nextObject;
-                stops[key] = [NSExpression expressionWithMGLJSONObject:valueExpression];
+            
+            NSAssert(curveParameters, @"curveParameters should be non-nil");
+            if (curveParameters) {
+                NSExpression *curveParameterExpression = [NSExpression expressionWithMGLJSONObject:curveParameters];
+                argumentObjects = [argumentObjects subarrayWithRange:NSMakeRange(1, argumentObjects.count - 1)];
+                NSExpression *inputExpression = [NSExpression expressionWithMGLJSONObject:argumentObjects.firstObject];
+                NSArray *stopExpressions = [argumentObjects subarrayWithRange:NSMakeRange(1, argumentObjects.count - 1)];
+                NSMutableDictionary *stops = [NSMutableDictionary dictionaryWithCapacity:stopExpressions.count / 2];
+                NSEnumerator *stopEnumerator = stopExpressions.objectEnumerator;
+                while (NSNumber *key = stopEnumerator.nextObject) {
+                    NSExpression *valueExpression = stopEnumerator.nextObject;
+                    stops[key] = [NSExpression expressionWithMGLJSONObject:valueExpression];
+                }
+                NSExpression *stopExpression = [NSExpression expressionForConstantValue:stops];
+                return [NSExpression expressionForFunction:@"mgl_interpolate:withCurveType:parameters:stops:"
+                                                 arguments:@[inputExpression, curveTypeExpression, curveParameterExpression, stopExpression]];
             }
-            NSExpression *stopExpression = [NSExpression expressionForConstantValue:stops];
-            return [NSExpression expressionForFunction:@"mgl_interpolate:withCurveType:parameters:stops:"
-                                             arguments:@[inputExpression, curveTypeExpression, curveParameterExpression, stopExpression]];
+            
         } else if ([op isEqualToString:@"step"]) {
             NSExpression *inputExpression = [NSExpression expressionWithMGLJSONObject:argumentObjects[0]];
             NSArray *stopExpressions = [argumentObjects subarrayWithRange:NSMakeRange(1, argumentObjects.count - 1)];
@@ -823,9 +828,14 @@ NSArray *MGLSubexpressionsWithJSONObjects(NSArray *objects) {
                     minimum = [NSExpression expressionWithMGLJSONObject:valueExpression];
                 }
             }
-            NSExpression *stopExpression = [NSExpression expressionForConstantValue:stops];
-            return [NSExpression expressionForFunction:@"mgl_step:from:stops:"
-                                             arguments:@[inputExpression, minimum, stopExpression]];
+            
+            NSAssert(minimum, @"minimum should be non-nil");
+            if (minimum) {
+                NSExpression *stopExpression = [NSExpression expressionForConstantValue:stops];
+                return [NSExpression expressionForFunction:@"mgl_step:from:stops:"
+                                                 arguments:@[inputExpression, minimum, stopExpression]];
+            }
+            
         } else if ([op isEqualToString:@"zoom"]) {
             return NSExpression.zoomLevelVariableExpression;
         } else if ([op isEqualToString:@"heatmap-density"]) {
@@ -1021,7 +1031,7 @@ NSArray *MGLSubexpressionsWithJSONObjects(NSArray *objects) {
         }
             
         case NSKeyPathExpressionType: {
-            NSArray *expressionObject;
+            NSArray *expressionObject = @[];
             NSArray *keyPath = [self.keyPath componentsSeparatedByString:@"."];
             for (NSString *pathComponent in keyPath) {
                 if (expressionObject) {
@@ -1030,6 +1040,8 @@ NSArray *MGLSubexpressionsWithJSONObjects(NSArray *objects) {
                     expressionObject = @[@"get", pathComponent];
                 }
             }
+            
+            NSAssert(expressionObject.count > 0, @"expressionObject should be non-empty");
             return expressionObject;
         }
             
diff --git a/platform/darwin/src/NSExpression+MGLPrivateAdditions.h b/platform/darwin/src/NSExpression+MGLPrivateAdditions.h
index 4ef49a2d15..54bc9068f4 100644
--- a/platform/darwin/src/NSExpression+MGLPrivateAdditions.h
+++ b/platform/darwin/src/NSExpression+MGLPrivateAdditions.h
@@ -13,8 +13,8 @@ NS_ASSUME_NONNULL_BEGIN
 
 @interface NSObject (MGLExpressionAdditions)
 
-- (NSNumber *)mgl_number;
-- (NSNumber *)mgl_numberWithFallbackValues:(id)fallbackValue, ... NS_REQUIRES_NIL_TERMINATION;
+- (nullable NSNumber *)mgl_number;
+- (nullable NSNumber *)mgl_numberWithFallbackValues:(id)fallbackValue, ... NS_REQUIRES_NIL_TERMINATION;
 
 @end
 
diff --git a/platform/darwin/src/NSPredicate+MGLPrivateAdditions.h b/platform/darwin/src/NSPredicate+MGLPrivateAdditions.h
index 1828009678..051a2775a1 100644
--- a/platform/darwin/src/NSPredicate+MGLPrivateAdditions.h
+++ b/platform/darwin/src/NSPredicate+MGLPrivateAdditions.h
@@ -10,15 +10,15 @@ NS_ASSUME_NONNULL_BEGIN
 
 - (mbgl::style::Filter)mgl_filter;
 
-+ (instancetype)mgl_predicateWithFilter:(mbgl::style::Filter)filter;
++ (nullable instancetype)mgl_predicateWithFilter:(mbgl::style::Filter)filter;
 
 @end
 
 @interface NSPredicate (MGLExpressionAdditions)
 
-- (id)mgl_if:(id)firstValue, ...;
+- (nullable id)mgl_if:(id)firstValue, ...;
 
-- (id)mgl_match:(NSExpression *)firstCase, ...;
+- (nullable id)mgl_match:(NSExpression *)firstCase, ...;
 
 @end
 
diff --git a/platform/ios/src/MGLMapView.h b/platform/ios/src/MGLMapView.h
index 607a197840..2423d62ee1 100644
--- a/platform/ios/src/MGLMapView.h
+++ b/platform/ios/src/MGLMapView.h
@@ -1130,7 +1130,7 @@ MGL_EXPORT
  `UIApplicationWillTerminateNotification`; you may receive a `nil` return value
  depending on the order of notification delivery.
  */
-- (MGLMapCamera *)cameraThatFitsCoordinateBounds:(MGLCoordinateBounds)bounds edgePadding:(UIEdgeInsets)insets;
+- (nullable MGLMapCamera *)cameraThatFitsCoordinateBounds:(MGLCoordinateBounds)bounds edgePadding:(UIEdgeInsets)insets;
 
 /**
  Returns the camera that best fits the given coordinate bounds, with the specified camera,
@@ -1150,7 +1150,7 @@ MGL_EXPORT
  `UIApplicationWillTerminateNotification`; you may receive a `nil` return value
  depending on the order of notification delivery.
  */
-- (MGLMapCamera *)camera:(MGLMapCamera *)camera fittingCoordinateBounds:(MGLCoordinateBounds)bounds edgePadding:(UIEdgeInsets)insets;
+- (nullable MGLMapCamera *)camera:(MGLMapCamera *)camera fittingCoordinateBounds:(MGLCoordinateBounds)bounds edgePadding:(UIEdgeInsets)insets;
 
 /**
  Returns the camera that best fits the given shape, with the specified camera,
@@ -1169,7 +1169,7 @@ MGL_EXPORT
  `UIApplicationWillTerminateNotification`; you may receive a `nil` return value
  depending on the order of notification delivery.
  */
-- (MGLMapCamera *)camera:(MGLMapCamera *)camera fittingShape:(MGLShape *)shape edgePadding:(UIEdgeInsets)insets;
+- (nullable MGLMapCamera *)camera:(MGLMapCamera *)camera fittingShape:(MGLShape *)shape edgePadding:(UIEdgeInsets)insets;
 
 /**
  Returns the camera that best fits the given shape, with the specified direction,
@@ -1187,7 +1187,7 @@ MGL_EXPORT
  `UIApplicationWillTerminateNotification`; you may receive a `nil` return value
  depending on the order of notification delivery.
  */
-- (MGLMapCamera *)cameraThatFitsShape:(MGLShape *)shape direction:(CLLocationDirection)direction edgePadding:(UIEdgeInsets)insets;
+- (nullable MGLMapCamera *)cameraThatFitsShape:(MGLShape *)shape direction:(CLLocationDirection)direction edgePadding:(UIEdgeInsets)insets;
 
 /**
  Returns the point in this view’s coordinate system on which to "anchor" in
diff --git a/platform/ios/src/MGLMapView.mm b/platform/ios/src/MGLMapView.mm
index cadf5be3fd..7365c02c29 100644
--- a/platform/ios/src/MGLMapView.mm
+++ b/platform/ios/src/MGLMapView.mm
@@ -2478,7 +2478,7 @@ public:
     }];
     [attributionController addAction:telemetryAction];
     
-    NSString *cancelTitle = NSLocalizedStringWithDefaultValue(@"CANCEL", nil, nil, @"Cancel", @"");
+    NSString *cancelTitle = NSLocalizedStringWithDefaultValue(@"CANCEL", nil, nil, @"Cancel", @"Cancel");
     UIAlertAction *cancelAction = [UIAlertAction actionWithTitle:cancelTitle
                                                            style:UIAlertActionStyleCancel
                                                          handler:NULL];
diff --git a/platform/ios/src/UIView+MGLAdditions.h b/platform/ios/src/UIView+MGLAdditions.h
index 85fea31ad2..ef074215b3 100644
--- a/platform/ios/src/UIView+MGLAdditions.h
+++ b/platform/ios/src/UIView+MGLAdditions.h
@@ -4,7 +4,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 @interface UIView (MGLAdditions)
 
-- (UIViewController *)mgl_viewControllerForLayoutGuides;
+- (nullable UIViewController *)mgl_viewControllerForLayoutGuides;
 
 - (NSLayoutYAxisAnchor *)mgl_safeTopAnchor;
 
diff --git a/platform/ios/vendor/SMCalloutView/SMCalloutView.m b/platform/ios/vendor/SMCalloutView/SMCalloutView.m
index 66a7b5a7a7..0520ba08a5 100755
--- a/platform/ios/vendor/SMCalloutView/SMCalloutView.m
+++ b/platform/ios/vendor/SMCalloutView/SMCalloutView.m
@@ -554,13 +554,18 @@ NSTimeInterval const kMGLSMCalloutViewRepositionDelayForUIScrollView = 1.0/3.0;
         stretch.toValue = presenting ? @1.0 : @0.0;
         animation = stretch;
     }
-    
+
+    NSAssert(animation, @"There should be an animation");
+
     // CAAnimation is KVC compliant, so we can store whether we're presenting for lookup in our delegate methods
     [animation setValue:@(presenting) forKey:@"presenting"];
     
     animation.fillMode = kCAFillModeForwards;
     animation.removedOnCompletion = NO;
-    return animation;
+    
+    // Cast as non-null to mute static analysis warning as documented at
+    // https://clang-analyzer.llvm.org/faq.html#decide_nullability
+    return (CAAnimation * _Nonnull)animation;
 }
 
 - (void)layoutSubviews {