manually inserting Exception

[vaudevillen]

So was thinking if we can call Bismarck.insert(Data), for whenever we might need to manually update Bismarck data, it might also be necessary to manually insert an error response.

For example, if the Fetcher just makes a get request, but later we need to make a put or a post, we would need to do that manually. If that network request has an error, shouldn't we also send that through to the eachError callback?

[asarazan]

I'm open to this idea, but it does have a whiff of broken abstraction to it. @treelzebub do you perchance have an opinion on this?

[treelzebub]

whoa i've missed a whole bunch of big changes up in hurrr. didn't know Fetcher was just a lambda now, but i'm into it. we've made error propagation Bismarck's job when it used to be Fetcher's, and imo that's a great move that gets rid of a bunch of duplicated effort.

to the question at hand, i'm not sure i understand: why would you want to insert an exception, and how would that even work if you have a Bismarck<MyDataClass>? i'm having trouble understanding how network errors getting fed to eachError is related to caching those errors.

[asarazan]

@treelzebub if you recall in the level days, we would do "optimistic" mutations on transactions, and that would involve injecting an updated value into the local store while we await the canonical value from a fetch.

Given that there is a good reason to override the authority of the data store, I think it definitely stands to reason that we might want to reflect a failed external operation here-- but similarly, this may just be an argument for punting the responsibility to the client to create a higher-level aggregator of errors, which is composed of bismarck errors, other systems etc...

[treelzebub]

punting the responsibility to the client to create a higher-level aggregator of errors, which is composed of bismarck errors, other systems etc...

this is kinda where i'm going with this. in my mind it's trivial to put your reactive element in the fetcher and propagate errors yourself. unless, of course, you're using LiveData, which is a thing that should in fact support error handling :P