[Bug]: MemoryRouter looses state of initial entries in v6.4.0

[ddolcimascolo]

What version of React Router are you using?

6.4.0

Steps to Reproduce

See the Sandbox at https://codesandbox.io/s/react-router-issue-9265-p8nx49 and simply downgrade react-router-dom to v6.3.0 to see the state value being rendered.

Expected Behavior

MemoryRouter does not loose state of initial entries.

Actual Behavior

MemoryRouter looses state of initial entries.

[ddolcimascolo]

This breaks Jest tests basically, where we use <MemoryRouter />.
The production application use <BrowserRouter /> is not impacted and works fine in v6.4.0.

[ddolcimascolo]

Am I the only one blocked by this?

Remix team, do you think this is something that can be fixed by someone that has never contributed to react-router? :)

[CarloHagens]

We are experiencing the same issue where we use the memory router with some initial state within our cypress component tests.

[ddolcimascolo]

@timdorr I saw your answer in #9273. Any chance this regression has the same cause?

[brophdawg11]

Thanks for the bug report and reproduction! Pushed a fix for this in #9288 and we should be able to get a patch out early this week 👍

[ddolcimascolo]

@brophdawg11 Is a release still planned this week?

[ddolcimascolo]

Thx for the release!

[brophdawg11]

👍 let us know if you run into any issues in 6.4.1!