[ios, macos] Fix a bug with multiple format expressions. (#14064)

Fixed a bug where `format` expressions using the generic `MGL_FUNCTION` binding ignored multiple formatting parameters.

2 files changed, 30 insertions, 1 deletions

diff --git a/platform/darwin/src/NSExpression+MGLAdditions.mm b/platform/darwin/src/NSExpression+MGLAdditions.mm
index 527cb64b3d..6aaba4dd90 100644
--- a/platform/darwin/src/NSExpression+MGLAdditions.mm
+++ b/platform/darwin/src/NSExpression+MGLAdditions.mm
@@ -1126,7 +1126,19 @@ NSArray *MGLSubexpressionsWithJSONObjects(NSArray *objects) {
                 if (firstOp.expressionType == NSConstantValueExpressionType
                     && [firstOp.constantValue isEqualToString:@"format"]) {
                     // Avoid wrapping format options object in literal expression.
-                    return @[@"format", self.arguments[1].mgl_jsonExpressionObject, self.arguments[2].constantValue];
+                    NSMutableArray *expressionObject = [NSMutableArray array];
+                    [expressionObject addObject:@"format"];
+                    
+                    for (NSUInteger index = 1; index < self.arguments.count; index++) {
+                        if (index % 2 == 1) {
+                            [expressionObject addObject:self.arguments[index].mgl_jsonExpressionObject];
+                        } else {
+                            [expressionObject addObject:self.arguments[index].constantValue];
+                        }
+                        
+                    }
+                    
+                    return expressionObject;
                 }
                 return self.arguments.mgl_jsonExpressionObject;
             } else if (op == [MGLColor class] && [function isEqualToString:@"colorWithRed:green:blue:alpha:"]) {
diff --git a/platform/darwin/test/MGLExpressionTests.mm b/platform/darwin/test/MGLExpressionTests.mm
index f869275dd3..bcc30e49fd 100644
--- a/platform/darwin/test/MGLExpressionTests.mm
+++ b/platform/darwin/test/MGLExpressionTests.mm
@@ -1002,6 +1002,23 @@ using namespace std::string_literals;
         XCTAssertThrowsSpecificNamed([expression expressionValueWithObject:nil context:nil], NSException, NSInvalidArgumentException);
     }
     {
+        NSExpression *expression = [NSExpression expressionWithFormat:@"MGL_FUNCTION('format', 'foo', %@, '\r', %@, 'biz', %@, 'bar', %@)", @{@"font-scale": @1.2}, @{}, @{@"font-scale": @1.0}, @{@"font-scale": @0.8}];
+        NSArray *jsonExpression = @[@"format", @"foo", @{@"font-scale": @1.2}, @"\r", @{}, @"biz", @{@"font-scale": @1.0}, @"bar", @{@"font-scale": @0.8}];
+
+        XCTAssertEqualObjects(expression.mgl_jsonExpressionObject, jsonExpression);
+        
+        NSExpression *encodedExpression = [NSExpression expressionWithMGLJSONObject:jsonExpression];
+
+        // Expressions encoded from a json create a different constant abstract type
+        // thus even tho knowing that the constant values are the same, the base
+        // class is not. This compares the resulting array which is type agnostic encoding.
+        for (NSUInteger index = 0; index < jsonExpression.count; index++) {
+            NSExpression *left = encodedExpression.mgl_jsonExpressionObject[index];
+            NSExpression *right = expression.mgl_jsonExpressionObject[index];
+            XCTAssertEqualObjects(left.mgl_jsonExpressionObject, right.mgl_jsonExpressionObject);
+        }
+    }
+    {
         NSArray *arguments = @[
             MGLConstantExpression(@"one"), MGLConstantExpression(@1),
             [NSExpression expressionForVariable:@"one"],