hey , I noticed weird behavior. We have a centralized entrypoint into apollo that uses the `watch` m...

# apollo-kotlin

[agrosner]

hey , I noticed weird behavior. We have a centralized entrypoint into apollo that uses the watch method. We have some calls that do not want to use a cache at all, so we use FetchPolicy.NetworkOnly . When watch executes, we always receive two network calls!
we have traced it down to this line in `watch`:

copy().fetchPolicyInterceptor(refetchPolicyInterceptor)
        .watch(response?.data) { _, _ ->

this line. since our request context has no cache interceptors, when the call is executed at this point, it always hits the network.

[mbonnin]

Howdy 🤠 . Not sure I'm following. Are you using .watch() together with FetchPolicy.NetworkOnly ?

[mbonnin]

apolloClient.query(MyQuery()).fetchPolicy(FetchPolicy.NetworkOnly).watch()

?

[mbonnin]

Or does your network query triggers a refetch on the watcher (that would be more likely I guess)

[agrosner]

Correct. Watch once with network only

[mbonnin]

SO you're doing something like this?

apolloClient.query(MyQuery()).fetchPolicy(FetchPolicy.NetworkOnly).watch()

[agrosner]

The subsequent emission is in the refetchPolicyInterceptor which has no caching execution comtext. So it hits network on second block

[mbonnin]

It's relatively unusual to call .watch() for a network only request. Any reason your not just calling .execute() ?

[agrosner]

i agree. we have a single entry point like:

private fun <D : Query.Data> fullQueryChain(
        query: Query<D>,
        params: ApolloQueryExecutor.Params,
        fetchPolicy: ApolloQueryExecutor.FetchPolicy
    ) = apolloClient.query(query)
     .fetchPolicy(fetchPolicy.toApolloFetchPolicy())
        .httpFetchPolicy(fetchPolicy.toHttpFetchPolicy())
        .httpExpireTimeout(params.httpExpirationInMillis)
        .watch(fetchThrows = true)

which allows different params to specify their own fetch policy. some requests may not want cache, while some do. so i figured using same place to determine that. it was unexpected behavior to hit a network call twice on watch.

[agrosner]

we switched to checking fetch policy and switching to toFlow() for the specified request instead of watch

[mbonnin]

👍 let us know if you want us to investigate the .watch() behaviour more. AFAIK, something like apolloClient.query(MyQuery()).fetchPolicy(FetchPolicy.NetworkOnly).watch() should only reach to the network once (because the refectPolicy defaults to CacheOnly ) but maybe there's more to it