iAPI: Merge of state and context after client-side navigation

[luisherranz]

Description

There's no way to distinguish the global state belonging to blocks that are inside a router region from the global state belonging to blocks that are not inside a router region. Therefore, we can't use the strategy of replacing the client state with the state coming from the server during client-side navigations.

Step-by-step reproduction instructions

1. Create a block that uses global state.
2. Place that block outside of a router region.
3. Navigate to a page where the global state is different from the initial page.
4. The state of the block was updated, which it shouldn't have, since it's outside a router region.

Screenshots, screen recording, code snippet

No response

Environment info

No response

Please confirm that you have searched existing issues in the repo.

• Yes

Please confirm that you have tested with all plugins deactivated except Gutenberg.

• Yes

[michalczaplinski]

If I understand correctly:

This assumes that the "new" page (the one that is navigated to in step 3.) loads some JS (typically the view.js file) that updates the global state?

[luisherranz]

No, it does refer to the state and context that is serialized from the server and how it merges with the existing state and context.

[luisherranz]

Completed in #62734.