cancellation too presumptive?

[redux-saga]

cancellation too presumptive?

[yelouafi]

I'm thinking of making this an opt-in behavior. Provide some config argument, so the developer can choose to disable the console warnings

[yelouafi]

Not sure I understand the issue. Saga cancellation exceptions are only thrown when yielding a cancel effect. But I dont see any cancel effect in the code above

Sorry, I left out an important piece - the root saga invoking this chain.

    function* root() {
        let process
        while (true) {
            yield take(SOME_TRIGGER)
            if (process && process.isRunning()) {
                yield cancel(process)
            }

            process = yield fork(fetchSomeStuff)
        }
    }

I use this pattern when the user can click on a list of items, and each click will trigger a data fetch for that item. If the user changes his mind and clicks on a different item while one is already loading, we can cancel the first data fetch.

It's not a huge ordeal, I'm just pointing out that when yield cancel(process) is triggered, it will throw SagaCancellationException in each branch of the fetchSomeStuff- which is fine, but it might be too ambitious to console.warn in each branch that doesn't explicitly handle that exception. I don't want to have to write a try/catch for every level of my saga if only one (bottom-most) or two (bottom most and top most) levels actually do anything after the exception.

[yelouafi]

but it might be too ambitious to console.warn in each branch that doesn't explicitly handle that exception

the warning is printed just to remind the developer in case he forgot to handle the cancellation. Which can lead to some mysterious bugs (inconsistent state)

I would 👍 that... perhaps just the NODE_ENV="production" convention. I have used that with something like envify in the past and it works well.

[yelouafi]

perhaps just the NODE_ENV="production" convention. I have used that with something like envify in the past and it works well.

Agree; I think it's a better idea

[gaearon]

Note that you'll want to make sure error behavior is exactly the same between prod and dev versions. If anything throws, it should throw in both cases. Logging a warning only in dev is fine though.

Looks like this was taken care of in https://github.com/yelouafi/redux-saga/blob/no-promise/src/proc.js#L79-L81

[yelouafi]

@aft-luke yes. Included with the new 0.6.0