v4: Using fetchMore and then refetch causes duplicated results.

[MechJosh0]

Describe the bug Using fetchMore and then refetch causes duplicated results.

To Reproduce Steps to reproduce the behavior:

1. Load results from backend using useQuery
2. Use fetchMore to load the next page
3. Perform a search on the results using refetch
   • You must only trigger refetch once, so if you're using a search input you should paste the search query in. Typing a query manually and performing more than 1 refetch will not reproduce the bug
   • You must produce this bug on the first refetch you perform, any following refetch calls will not reproduce the bug
   • The bug will only be reproducible on the first time you do it, to reproduce it again you have to reload
   • The found item does not have to be in memory, reproducible either way

What happens The results found are duplicated from useQuery.

Expected behaviour The results should only be what was discovered from the Graph call to the backend that came from your refetch call.

Versions vue: 2.6.11 vue-apollo: v4.0.0-alpha.10 apollo-client: 2.6.10

Additional context During the steps to reproduce, if you watch the Ref result from useQuery you will notice how result changes twice. The first instance will be the correct value and the second time it's the incorrect value due to duplicated items.

You will also notice that when you perform your refetch it will only do one Graph backend call, which is expected. The results returned from the server are the correct results. Only one Graph call is perform but watching result from useQuery is still triggered twice with the correct and then incorrect value).

[Jesseyx]

Have the same issue!

[Akryum]

Are you using Apollo Client 3 or 2?

[Jesseyx]

Versions @apollo/client: 3.3.11 @vue/apollo-composable: 4.0.0-alpha.12 vue: 3.0.5

[Akryum]

Maybe related to https://github.com/apollographql/apollo-client/issues/6916

[dominikklein]

I think it's not completely related to this bug.

Currently, I have also a problem in that my watcher on the result is triggered twice when I use the refetch. In the code, I saw that there is a processOnResult triggered directly from the refetch function and also from the onNextResult, when something really changed in the result or a "no cache" policy is used.