Null Reference Exceptions with Complex Nested Schemas

[houstonhaynes]

Hawaii crashes with NullReferenceException when processing complex OpenAPI schemas that have nested Content["application/json"] structures without proper null checks.

Error Example

Unhandled exception. System.NullReferenceException: Object reference not set to an instance of an object.
   at Hawaii.Program.processResponse(OpenApiResponse response, String operationId)

CloudflareFS Workaround

We fixed this in a local fork of Hawaii with additional null safety checks:

Files Modified: \Hawaii\src\Program.fs, \Hawaii\src\OperationParameters.fs

// Before (crashed):
let mediaType = response.Value.Content.["application/json"]
if not (isNull mediaType.Schema) then ...

// After (works):
if not (isNull response.Value.Content) &&
   response.Value.Content.ContainsKey "application/json" then
    let mediaType = response.Value.Content.["application/json"]
    if not (isNull mediaType) && not (isNull mediaType.Schema) then ...

Impact

• Before fix: Could not generate Workers Management API (crashed)
• After fix: Successfully generates 200KB+ of F# code for Workers API

Recommendation

The patches are straightforward defensive coding that handle edge cases in complex OpenAPI specs. A more elegant solution may be possible, but I'll post a draft PR with the fixes from my fork for your review.