How can I configure an OpenAPI schema for an array to ignore or handle malformed elements?

Unfortunately, there isn’t a built‐in way within the OpenAPI (or JSON Schema) specification to “skip” invalid array items or dynamically transform them into a fallback object like an InvalidEvent. The schema only describes the expected structure; if one element doesn’t match, the generated/parsing code (or client library) typically fails on the entire array.

Workarounds

1. Custom Deserialization/Parsing Logic:
   Instead of using the autogenerated code verbatim, you can override the JSON parser on iOS. For example, you could parse the response as a JSON array and then iterate over each element. For each element, attempt to deserialize into an Event. If deserialization fails for a particular element, you can either ignore it or wrap it into a fallback structure (like an InvalidEvent). This gives you full control over error handling.

   SWIFTCopied
   // Example in Swift (using Codable and manual filtering)
   struct Event: Codable { /* your valid event structure */ }
   struct InvalidEvent {
       let id: Int?
       let error: Error
   }
   
   enum ParsedEvent {
       case valid(Event)
       case invalid(InvalidEvent)
   }
   
   func parseEvents(from data: Data) -> [ParsedEvent] {
       guard let jsonArray = try? JSONSerialization.jsonObject(with: data) as? [Any] else {
           return []
       }
       
       var parsedEvents: [ParsedEvent] = []
       
       for jsonItem in jsonArray {
           do {
               let eventData = try JSONSerialization.data(withJSONObject: jsonItem)
               let event = try JSONDecoder().decode(Event.self, from: eventData)
               parsedEvents.append(.valid(event))
           } catch {
               // Optionally extract id or other debug info from jsonItem if available.
               let invalid = InvalidEvent(id: (jsonItem as? [String: Any])?["id"] as? Int, error: error)
               parsedEvents.append(.invalid(invalid))
           }
       }
       return parsedEvents
   }

2. Vendor Extensions and Custom Code Generation:
   Some code generators allow using vendor extensions (with names starting with x-) to customize behavior. You could inspect your code generator’s documentation to see if there’s a way to instruct it to wrap array elements in a custom deserializer. However, this isn’t standardized and may not be available in your toolchain.

3. Alternative Schema Designs:
   In theory, you could try using oneOf in your schema in an attempt to allow either a valid Event or an “error” placeholder:

   YAMLCopied
   EventOrError:
     oneOf:
       - $ref: "#/components/schemas/Event"
       - type: object
         properties:
           invalidEvent:
             type: string
         required:
           - invalidEvent

   And then change your array to reference EventOrError. But note that this only works if you can modify both the API response and the client logic. With third-party or out-of-control sources, this approach may not be feasible.

Conclusion

There is no declarative way in OpenAPI to instruct generated code to silently ignore or convert malformed array elements. The robust solution is to implement custom parsing logic that can handle individual deserialization errors, allowing your application to either filter out or log invalid events without crashing the parsing of the entire array.