[fzaninotto]

Problem

Fixes #11431

InternalRouter calls createHashRouter in its render body, so every rerender of the component rendering <Admin> discards the router and creates a new one at the current URL. A navigation scheduled on the previous router then updates the URL without the current router ever seeing it: the URL becomes #/login but the page stays blank.

This happens whenever something above <Admin> rerenders while authProvider.logout() runs - a common pattern with auth SDKs, which notify a context provider when the session is cleared.

Router state that does not live in the URL is lost the same way. A navigation blocked by useBlocker (the "unsaved changes" guard) silently disappears when the parent rerenders.

Solution

Create the router once.

The router keeps the route element it was created with, so that element can no longer close over the children, or the whole tree under <Admin> would be frozen at its first render (dynamic resources, routes behind permissions, anything passed down from above <Admin> would stop updating). It now reads the children from a context placed above the RouterProvider, so children updates still reach the router.

The basename can only be set when the router is created, so RouterWrapper remounts InternalRouter when it changes. A basename change therefore recreates the router, as before - but a plain rerender no longer does.

How To Test

yarn test-unit packages/ra-core/src/routing/adapters

The three tests each fail without the corresponding part of the fix:

• should not lose the navigation state when the parent rerenders - a navigation blocked by useBlocker survives a parent rerender
• should rerender the children when the parent rerenders - the tree under <Admin> still receives updates
• should take the new basename into account when it changes

The blank page from the issue itself only reproduces with React 19 and react-router 7, so it is not covered by a unit test here; it was verified manually with the issue's reproduction (react-admin built from this branch, React 19.3.1, react-router 7.18.4): the login page now renders instead of a blank page.

Additional Checks

• The PR targets master for a bugfix or a documentation fix, or next for a feature
• The PR includes unit tests (if not possible, describe why)
• The PR includes one or several stories (not applicable: internal router lifecycle, no visual surface)
• The documentation is up to date (no documentation change required)

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