Hey guys,

I would like to know how I can catch an error in a stream and stop the execution. Due to the fact that I did not find an answer, I assume I am taking a wrong approach here. I would appreciate any kind of feedback!

Here is my Code:

func fetchEntries() -> Future<[Entry],EntryGenerationError> {
    return Future { [weak self] promise in
        guard let strongSelf = self else {
            promise(.failure(.selfNotStrong))
            return
        }
        strongSelf.entityController.fetchAllEncodedEntries { encodedEntries in
            let publishersOfDecodedEntries = encodedEntries.map({ strongSelf.decodeEntry(entry: $0) })
            Publishers.MergeMany(publishersOfDecodedEntries)
                .catch({ err in
                    promise(.failure(err))
                    //FINISH HERE
                })
                .collect()
                .sink { encodedEntries in
                    ...
                    promise(.success(finalEntries))
                }
        }
    }
}

With the caveat that I really haven't delved too deeply into Combine yet...

It's not intended for you to drop out of the pipeline from a .catch() operator. Instead, you substitute the failed Publisher with a new Publisher and pass that through the rest of the pipeline.

See:

Error handling in Combine explained with code examples

Understanding Combine