Synchronous Lambda callback causes undesirable second captureException call #2956

See example event here: null.<anonymous>

Package + Version

• @sentry/serverless

Version:

5.25.0

Description

If the callback-based lambda invocation is used, as opposed to the Promise-based style, then @sentry/serverless pushes the error correctly, but then also sends an empty exception. The reason is because this line:

calls captureExceptionAsync with the error correctly, but then also calls .finally(... reject(callback(...))

which rejects this awaited promise with undefined (the return value of calling callback):

which causes execution to drop into the catch block below which then calls captureExceptionAsync again, but this time passing undefined as e:

Solution

I guess the catch block could no-op if e === undefined or you could change the callbackWrapper

// from:
captureExceptionAsync(args[0], context, options).finally(() => reject(callback(...args)));

// to:
callback(...args);
reject(args[0]);

as that would then push the error through the catch block instead of the result of callback, and would also honour the rethrow option.