[v3.4 Regression] Changing variables uses nextFetchPolicy instead of fetchPolicy

Intended outcome: I have a query with fetchPolicy: 'network-only' and nextFetchPolicy: 'cache-first'. When I change the variables, it should fetch new results from the server regardless of what’s in the cache.

Actual outcome: Changing the variables appears to use the nextFetchPolicy and does not fetch new data from the server.

How to reproduce the issue: https://github.com/dylanwulf/react-apollo-error-template/tree/changing-variables-nextFetchPolicy Please use branch changing-variables-nextFetchPolicy. Reproduction instructions: Open dev tools and watch the console. Click any of the unselected radio buttons, see that a request to the server is made (this is printed to the console instead of the network tab due to the apollo link). Click “All”, see that a request to the server is NOT made.

It looks like this problem first showed up in v3.4.0-rc.5 and still exists in v3.4.0-rc.14

[benjamn]

Alright, except for the weirdness about notifyOnNetworkStatusChange: false not working with React and useQuery, I believe this is fixed in @apollo/client@3.4.0-rc.18. Thanks for pushing this issue (and #6839) forward @dylanwulf!

[benjamn]

@dylanwulf The operative change in 3.4.0-rc.5 was the addition of this line in PR #8346: https://github.com/apollographql/apollo-client/blob/f11a163a4e507441bd51c2e0f9571aad853d5856/src/react/data/QueryData.ts#L203 Calling applyNextFetchPolicy here advances immediately to nextFetchPolicy without ever using fetchPolicy, which seems incorrect to me. Removing this line fixes the reproduction you provided, though you might want to remove notifyOnNetworkStatusChange: true from your useQuery options to avoid receiving intermediate loading: true results with cache data.

On a more general note, since you mentioned #6839, I have to admit I’m not comfortable with the role useQuery plays in resetting fetchPolicy and nextFetchPolicy, which happens simply because useQuery is called again with (very likely) the same initial options object, every time the component rerenders. I happen to think fetchPolicy should be reset when variables change, but I don’t think useQuery is the right/best mechanism to accomplish that.