Scope Login/Logout impersonation clear to the impersonator's guard

[chengkangzai]

Problem

FilamentImpersonateServiceProvider::registeringPackage() clears impersonation on every Login/Logout event, ignoring which guard fired it:

Event::listen(Login::class,  fn () => Impersonation::clear());
Event::listen(Logout::class, fn () => Impersonation::clear());

In apps that share a single session across multiple guards (e.g. an admin guard alongside a separate customer/storefront guard on the same domain), this is unsafe. While an admin is impersonating, an unrelated guard authenticating — a customer logging in on the storefront, or a "remember me" recaller silently re-authenticating on a plain GET — fires a Login/Logout and tears the impersonation down.

The impersonator's own session login key is left untouched, so they remain authenticated as the impersonated user, but isImpersonating() now returns false: the banner disappears and there's no way to leave. The admin is silently stuck as the impersonated user.

Fix

Only end the impersonation when the auth event belongs to a guard involved in the impersonation (the impersonator's guard, or the guard being used):

protected function clearImpersonationForGuard(?string $guard): void
{
    if (Impersonation::isImpersonating()) {
        $impersonationGuards = array_filter([
            Impersonation::getImpersonatorGuardName(),
            Impersonation::getImpersonatorGuardUsingName(),
        ]);

        if ($guard !== null && $impersonationGuards !== [] && ! in_array($guard, $impersonationGuards, true)) {
            return;
        }
    }

    Impersonation::clear();
}

Backward compatibility

• Single-guard apps: the event guard always matches the impersonator guard, so behaviour is identical.
• Not impersonating: falls through to Impersonation::clear() exactly as before (e.g. clearing stray keys on a fresh login).
• Impersonator's own guard logs in/out: still clears — a real login/logout ends the impersonation as expected.
• Only a foreign guard's auth event is now ignored.

Tests

Adds tests/ImpersonationClearOnAuthEventTest.php covering both paths (unrelated guard preserves; impersonator guard clears; not-impersonating unchanged). Full suite passes locally (135 passed).