"Store reset while query was in flight(not completed in link chain)" when stopQuery is called right after resetStore. Race condition?

Currently, queries are getting stuck in the QueryManager.fetchQueryPromises Map when stopQuery is called while that query is in flight.

Inside QueryManager.fetchQuery a subscription is added to the QueryInfo (QueryManager.query object) of the Observable representing the current request.

      this.setQuery(queryId, ({ subscriptions }) => ({
        subscriptions: subscriptions.concat([subscription]),
      }));

On the subscription, callbacks are set up to remove the queryId from QueryManager.fetchQueryPromises

        error: (error: ApolloError) => {
          this.removeFetchQueryPromise(requestId);
          // ...
        },
        complete: () => {
          this.removeFetchQueryPromise(requestId);
          // ...
        },

When stopQuery() is called before this query resolves, the promise will stay in that map because the subscription has been removed, therefore the callbacks to remove it will no long trigger.

  public stopQuery(queryId: string) {
    this.stopQueryInStore(queryId);
    this.removeQuery(queryId);
  }

  public removeQuery(queryId: string) {
    const { subscriptions } = this.getQuery(queryId);
    // teardown all links
    subscriptions.forEach(x => x.unsubscribe());
    this.queries.delete(queryId);
  }

Later on, this will cause problems when one tries to call resetStore()

  public resetStore(): Promise<ApolloQueryResult<any>[]> {
    return this.clearStore().then(() => {
      return this.reFetchObservableQueries();
    });
  }

  public clearStore(): Promise<void> {
    this.fetchQueryPromises.forEach(({ reject }) => {
      reject(
        new Error(
          'Store reset while query was in flight(not completed in link chain)',
        ),
      );
    });
    // ...
  }

Error: Network error: Store reset while query was in flight(not completed in link chain)
    at new ApolloError (bundle.umd.js:124)

Intended outcome: I think queries should be removed from that Map after subscriptions get removed.

So as a solution, I might suggest that as part of the clean up for stopQuery, that the requestId should be removed from QueryManager.fetchQueryPromises. Perhaps there is a cancel method to evoke, or I should reject the promise with a new Error that the query has been cancelled.

Actual outcome: Queries are staying in that Map.

How to reproduce the issue: It’s an edge case, but this is how I ran into this issue through react-apollo:

• Render a Query wrapped component.
• Call resetStore() via user interaction
• Immediately trigger a state change that results in that Query component being unmounted.

Versions

 apollo-client: 2.3.5
 react-apollo: 2.1.9

In hindsight I should have just written a PR instead.

[qeternity]

Can confirm this is still an issue

[JanSmolko]

If somebody has still this issue… I resolved it with stop() before clearStore()

...
client.stop()
client.clearStore()
...