Possible inconsistency with isError and error when using keepPreviousData: true

[tannerlinsley]

• Turn on keepPreviousData: true
• Template using isError, not error, to detect an error state
• Fire a query that resolves and displays normally
• Fire a query that fails and introduces an error state
• The isError state is false, but there is clearly an error present.

I think the desired effect is that if an error is encountered in the new/latest query, the status should not be success with the previous data, but error with the new query.

Codesandbox: https://codesandbox.io/s/optimistic-hooks-n5v12?file=/src/index.js

[TkDodo]

if we don't want to keep anything in case of error (not even the existing previous data), I think it would be as simple as adding a check for status !== 'error' to this check:

https://github.com/tannerlinsley/react-query/blob/78a1e8a37ed80944e60559c0fde9fc6172a77bfe/src/core/queryObserver.ts#L367-L377

[tannerlinsley]

🎉 This issue has been resolved in version 3.6.0 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

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