clearing out errors when fetchMore is called

[prybalko]

This fixes #2533. Does this seem like a reasonable amendment?

Checklist:

• If this PR is a new feature, please reference an issue where a consensus about the design was reached (not necessary for small changes)
• Make sure all of the significant new logic is covered by tests
• If this was a change that affects the external API used in GitHunt-React, update GitHunt-React and post a link to the PR in the discussion.

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[prybalko]

^

[jbaxleyiii]

@prybalko this may work, can you add a test to show the issue and how this fixes it?

[kennethlynne]

Please get this in

[jbaxleyiii]

@kennethlynne would you be able to pick up this PR and add a couple test cases for it?

[sondremare]

I will take a look at it, later this week (maybe tomorrow).

[sondremare]

I still receive the same error even with this fix

Uncaught (in promise) TypeError: Cannot set property 'networkStatus' of undefined
    at QueryStore.initQuery (queries.js:65)
    at QueryManager.fetchQuery (QueryManager.js:181)
    at ObservableQuery.js:163
    at <anonymous>

[sondremare]

I need some help here @jbaxleyiii. This is how I have observed fetch-more to work in apollo.

1. User opens page with associated query. Query is given an id 1, and fetched from backend
2. User wants to fetch more. Query is given a new id of 2, and the fetchMoreForQueryId is set to the original query's id, namely 1.
3. Fetch more fails due to spotty/no network.
   4a) User regains network and tries to fetch more again. Null pointers and hell breaks loose. Query is unable to recover
   4b) User is still without network and tries to fetch more again, same thing occurs. Null pointers and hell breaks loose.

Not having as much intimate knowledge of the workings of apollo, I am unsure of how to recover here. When fetch more fails. should we reassign the original query back to query id 1, since we have that in cache. And only error out the fetchMore (query with id 2)? Or is there something major/minor I am missing here?

Reproducible repo for apollo 2 here: https://github.com/sondremare/react-apollo-fetch-more-error

[jbaxleyiii]

@sondremare I'll take a look! This is definitely something that needs to be fixed!

[sondremare]

@jbaxleyiii You probably have seen it, but I have a PR here #2906 that seems to fix the problem if used alongside react-apollo 2.1.0-beta, according to discussion in #2539

[hwillson]

As mentioned in #2533 (comment), this is no longer an issue (verified against apollo-client 2.3.1). Thanks very much for working on this!