标签：#rfc7807

Problem My script failed when try lacked an explicit import from dw::Runtime . The runtime reported Unable to resolve reference of: try during execution. The documentation describes try as a function that returns a Result object for handling errors docs . Input { "order" : { "id" : "ORD-2001" , "total" : "12.5O" } } Working configuration %dw 2.0 // try() lives in dw::Runtime — not imported by default import try from dw::Runtime // RFC 7807 media type is accepted as-is by the JSON writer output application/problem+json var attempt = try(() -> payload.order.total as Number) --- if (attempt.success) { total: attempt.result } else { "type": "https://example.com/problems/invalid-total", "title": "Invalid order total", "status": 400, "detail": attempt.error.message, "instance": "/orders/" ++ payload.order.id, "errorKind": attempt.error.kind } Output { "type" : "https://example.com/problems/invalid-total" , "title" : "Invalid order total" , "status" : 400 , "detail" : "Cannot coerce String (12.5O) to Number" , "instance" : "/orders/ORD-2001" , "errorKind" : "InvalidNumberException" } The detail field contains the string Cannot coerce String (12.5O) to Number . The errorKind field holds the value InvalidNumberException . The trap The missing import causes a resolution failure when the script executes. Running fail_noimport.dwl produces an exit code of 255 and reports Unable to resolve reference of: try . What I do now I always add import try from dw::Runtime at the top of every script that uses the function. I verify the import exists before running the transformation to prevent resolution errors. Runs shown: DataWeave CLI 2.12.2 102 DataWeave patterns + 8 Exchange modules with 208 MUnit tests: github.com/shakarbisetty/mulesoft-cookbook | 60-second walkthroughs: youtube.com/@SanThaParv